• 专利附录
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    • 专利摘要:
    System for the electromagnetic characterization of isotropic and anisotropic materials in a non-destructive way comprising a sensor (s1) of microstrip or coplanar type in open circuit, and a measurement equipment (me) for measurements in reflection as a function of frequency. The sensor (s1) contacts at one end with the surface of the material (m) to be characterized and on the other it is connected to the unit of measurements (em) by means of a transmission guide (g1) and two transitions: (t1) the transition between the sensor (s1) and the transmission guide (g1) and (t2) makes the transition between the transmission guide (g1) and the measurement equipment (em). A second sensor (s2) placed at 90º with respect to the first sensor (s1) is provided to characterize uniaxial anisotropic materials. A third sensor (s3) is provided, the three sensors being oriented in a coordinate system (x, y, z) to characterize biaxial anisotropic materials. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2611553A1
    申请号:ES201630964
    申请日:2016-07-14
    公开日:2017-05-09
    发明作者:Juan HINOJOSA JIMENEZ；Félix Lorenzo MARTINEZ VIVIENTE；Alejandro MELCON ALVAREZ
    申请人:Universidad Politecnica de Cartagena；
    IPC主号:
    专利说明:



    SYSTEM AND METHOD FOR ELECTROMAGNETIC CHARACTERIZATION OFMATERIALS
    Field of the Invention
    The need to elaborate materials with specific characteristics for different applications in sectors of activity as diverse as electronics, information and communications technologies, health or agrifood, has allowed the creation of an important field within high electronics frequencies The invention uses the interaction of electromagnetic waves with a material to measure its intrinsic parameters in the range of radio frequencies (RF) / microwaves, since the propagation characteristics of electromagnetic waves in a material depend on their physical-chemical parameters . These propagation characteristics can be related to two intrinsic complex parameters of the material subjected to the interaction test:
    '' '' ''
    the permittivity (  j) and the permeability (  j). The measurement of these two parameters allows to contribute to the internal knowledge of the material under test.
    State of the art
    Numerous electromagnetic characterization techniques of materials have been developed to obtain these parameters [L. F. Chen, C. K. Ong, C. P. Neo, V. V. Varadan and V. K. Varadan, “Microwave electronics: Measurement and materials characterization”, Chichester (England): Wiley, 2004 (Chen2004)]. Except measures without contact with the material to be characterized, such as those based on free space by means of antennas [D. K. Ghodgaonkar, V. V. Varadan, and V. K. Varadan, “Free-space measurement of complex permittivity and complex permeability of magnetic materials at microwave frequencies”, IEEE Transactions on Instrumentation and Measurement, vol. 39, pp. 387-394, April 1990 (Ghodgaonkar1990)], the others use a sensor connected to a measuring device that allows to acquire some electrical and / or magnetic parameters. At low frequencies (<1GHz), an impedance analyzer is usually used to measure capacities and inductances, while for high frequencies (> 1GHz) a vector network analyzer is used. The vector network analyzer allows the analysis of the properties of electrical networks, associated with the reflection and transmission of complex electrical signals, known as dispersion parameters (S parameters). In general, electromagnetic characterization techniques based on a sensor


    they usually have a sample of the material to be measured within the sensor and, therefore, the measurements are characterized by being destructive. Currently, the characterization methods that perform non-destructive measurements of materials usually use two types of sensors in open circuit: coaxial or rectangular guide [M. A. Stuckly, and S. Stuchly, "Coaxial line reflection methods for measuring dielectric properties of biological substances at radio and microwave frequencies-A review", IEEE Transactions on Instrumentation and Measurement, vol. 29, pp. 176-183, September 1980 (Stuchly1980)], [V. Teodoridis, T. Sphicopoulos, and F. E. Gardiol, "The reflection from an open-ended rectangular waveguide terminated by a layered dielectric medium", IEEE Transactions on Microwave Theory and Techniques, vol. 33, pp. 359-366, May 1985 (Teodoridis1985)]. The principle of measurements for both sensors is to apply the open circuit end on the material to be characterized. The coaxial sensor in open circuit, which is limited to parameter measurements of isotropic materials, while the sensor in rectangular guide in open circuit also allows measurements of anisotropic materials [CW Chang, KM Chen, and J. Qian, "Non-destructive measurements of complex tensor permittivity of anisotropic materials using a waveguide probe system ”, IEEE Transactions Microwave Theory and Techniques, vol. 44, pp. 1081-1090, July 1996 (Chang1996)]. However, the latter requires a larger volume of material (isotropic or anisotropic) and several sensors of different sizes to cover a wide range of frequencies.
    The first electromagnetic characterization techniques to extract the intrinsic properties of materials in the range of radio frequencies (RF) and microwaves date back to the 1950s [A. R. Von Hippel, Ed., "Dielectric Materials and Applications", New York (USA): Wiley, 1954. (VonHippel1954)]. However, it was when the network analyzers, scalar in the first time and later vector, with higher performance and with affordable prices, gained in popularity against inadequate instrumentation, that a lot of RF / microwave techniques were developed and applied of electromagnetic characterization of materials [Chen2004]. These developments were made due to the great interest that they aroused and continue to originate in different sectors of activity such as electronics, information and communications technologies, health, agri-food, etc., given that these methods of characterization in the range of Microwaves contribute to providing information on the microscopic and macroscopic properties of a wide variety of solid, semi-solid (dusty, gels) and liquid materials.


    The responses of a material to external electromagnetic fields can be determined
    '' '
    through two complex parameters called permittivity (  j) and
    '' '
    permeability (  j). Permitivity describes the interaction of a material with an external electric field applied to it, while permeability describes the interaction of a material with an external magnetic field.
    Microwave techniques for electromagnetic characterization (permittivity, permeability) of RF / microwave materials can be classified into two categories: resonant methods and non-resonant methods [Chen2004]. In general, resonant methods with respect to non-resonants have greater precision and are more suitable for measurements of materials with low losses. Non-resonant methods are often used to obtain the general electromagnetic properties of a material in a wide frequency range, while resonant methods can only extract precise electromagnetic characteristics of a material at a fixed frequency or several discrete frequencies. The sensors of the present invention are based on microstrip, coplanar and alternative configurations open circuit transmission guides, and are framed in the category of non-resonant electromagnetic characterization methods. For this reason, reference is made to the background of this category.
    In the literature, a wide variety of sensors used in non-resonant electromagnetic characterization methods are available to cover a wide range of frequencies. Non-resonant electromagnetic characterization methods include measurement techniques in reflection and reflection / transmission. With this last technique (reflection / transmission), according to the properties of the material to be characterized and the sensor used, four parameters such as permittivity can be extracted from the measurements
    '' '' ''
    complex (  j) and complex permeability (  j) or two components of complex permittivity of a tensioner [1], assuming that the anisotropic material to be characterized is not magnetic. The main sensors used in reflection / transmission techniques are based on measurements in free space and transmission guide with a quadrupole configuration (two ports). The measurements in free space need to insert the material to be characterized between two antennas by means of a sample holder [Ghodgaonkar1990]. These characterization techniques are very precise. However, at low microwave frequencies (<5 GHz), free space characterization techniques are usually not adequate when a small amount of material to be characterized is available, since it requires a large size


    of the same. On the other hand, the transmission guide sensors need a smaller amount of the material to be characterized, since the dimensions of their structures are smaller. Transmission guidance sensors can be classified into two categories: those with a closed structure and those with a semi-open structure. Depending on the sensor used, the material to be characterized (solid, semi-solid or liquid) will be inserted into a closed guide, placed on top of a semi-open guide or used as a means of propagation (only for solid materials and compacted powders) in manufacturing of a semi-open guide. The main sensors in closed transmission guides are coaxial [A. M. Nicolson, and G. F. Ross, “Measurement of the intrinsic properties of materials by time-domain techniques”, IEEE Transactions on Instrumentation and Measurement, vol. 19, pp. 377-382, November 1970 (Nicolson1970)], rectangular [W. B. Weir, “Automatic measurement of complex dielectric constant and permeability at microwave frequencies”, Proceedings of the IEEE, vol. 62, pp. 33-66, January 1974 (Weir1974)], or stripline [W. Barry, "A broad-band, automated, stripline technique for simultaneously measurement of complex permittivity and permeability", IEEE Transactions Microwave Theory and Techniques, vol. 34, pp. 80-84, January 1986 (Barry1986)], while semi-open ones are microstrip or coplanar [M.D. Janezic, and D.F. Williams, "Permittivity characterization from transmission line measurements", IEEE Microwave Symposium Digest, 8-13 June 1997, vol. 3, pp. 1343-1345, Denver (USA) (Janezic1997)], [S.
    S. Stuchly, and C. E. Bassey, "Microwave coplanar sensors for dielectric measurements", Measurement Science and Technology, vol. 9, pp. 1324-1329, August 1998 (Stuchly1998)],
    [J. Hinojosa, L. Faucon, P. Queffelec and F. Huret, “S-parameter broadband measurements of microstrip lines and extraction of the substrate intrinsic properties”, Microwave and Optical Technology Letters, vol. 30, pp. 65-69, July 2001 (Hinojosa2001a)], [J. Hinojosa, “Sparameter broadband measurements on-coplanar and fast extraction of the substrate intrinsic properties”, IEEE Microwave and Wireless Components Letters, vol. 11, pp. 80-82, February 2001 (Hinojosa2001b)].
    A transmission guide can support a finite number of propagation modes at a certain frequency. In the case of a multimode propagation, electromagnetic energy is distributed among all modes which produces distortion, since the constant and the propagation speed of each mode are different. Therefore, it is convenient to work in a frequency range whose propagation is single mode (fundamental mode). The different propagation modes are: electric transverse (TE), magnetic transverse (TM), electromagnetic transverse (TEM) or hybrid. The


    TE and TM modes are very dispersive and usually propagate in rectangular waveguides. For the TE mode there is no electric field component in the propagation direction, while for the TM mode the magnetic field component is null. The TEM mode is propagated in transmission guides with at least two conductors and evenly filled with a dielectric material such as coaxial and stripline guides. For TEM mode, there is no component of the electric and magnetic field in the propagation direction and the guide allows the propagation of RF / microwave signals without blocking DC currents. Finally, the hybrid mode is propagated in transmission guides where the components of the electric and magnetic field in the propagation direction are not zero. Semi-open transmission guides such as microstrip and coplanar transmission guides have a hybrid propagation mode, since they have an abrupt air-dielectric transition that prevents having a TEM propagation mode. However, the distribution of its electric and magnetic fields is very similar to that of the TEM mode and, therefore, the hybrid mode in these guides is called quasi-TEM. In addition, being built with two or more conductors, the microstrip and coplanar guides allow the propagation of RF / microwave signals and DC currents.
    The measurements with closed and semi-open sensors in transmission guide where it is inserted
    or a solid material is placed may be inaccurate, due to the presence of some unwanted spaces (gaps) between the walls of the conductors of the transmission guide and the inserted material. However, this does not happen with semi-open sensors whose microstrip or coplanar transmission guides are made of the same material as the material to be characterized. In addition, modifying the width of the microstrip transmission guide
    or coplanar, its characteristic impedance can be adjusted. In this way, it is possible to optimize its configuration in order to propagate the fundamental quasi-TEM mode and make precise measurements with the same microstrip or coplanar sensor over a wide frequency range. The main drawback of the microstrip and coplanar semi-open sensors manufactured in the material to be characterized with respect to the other sensors, is the difficulty of measuring materials with low losses, due to the metallic losses produced by these transmission guides [Janezic1997]. Except for liquid and semi-solid materials such as gels, all these sensors require a process of conditioning the material (solid) to be characterized in order to insert it or place it in the closed or semi-open transmission guide.


    The closed or semi-open transmission guide sensors used in reflection / transmission measurements are easy to adapt for use in non-resonant techniques based on reflection measurements [Stuchly1980], [J. Hinojosa, "Permittivity characterization from open-end microstrip line measurements", Microwave and Optical Technology Letters, vol. 49, pp. 1371-1374, June 2007 (Hinojosa2007)]. To do this, you need to transform the quadrupole configuration (two ports) into a dipole configuration (one port), leaving one of the two ports of the transmission guide closed or semi-open with one of the three possible terminations: impedance, open circuit or short circuit Reflection methods with transmission guide sensors with short-circuit termination usually have the material to be characterized as electrically short-circuited and are usually used to extract the complex permeability of the measurements, since these are not sensitive to permittivity. On the other hand, reflection methods with transmission guidance sensors with open circuit terminations or impedance are usually used for complex permittivity measurements, assuming that the material to be characterized is not magnetic.
    Prior techniques with sensors in dipole and quadrupole configurations (coaxial, rectangular, stripline, microstrip, coplanar) have the common disadvantage of being destructive methods and of not being able to perform measurements in vivo. This drawback is due to the need to condition the material to characterize the sensor in dipole or quadrupole configuration. In the case of a solid material, machining processes are required to be able to insert or place it in the sensor, while for the semi-solid materials (powder, gel) and liquids a sample must be taken to fill the sensor. This problem can be overcome by non-destructive reflection methods that facilitate in vivo and in situ measurements of a wide variety of solid, semi-solid and liquid materials. In this way, the procedure for carrying out the measurements is considerably shortened, since the machining time of the solid materials and the semisolid and liquid sampling to be introduced into the sensor is suppressed. These non-destructive reflection methods use open circuit sensors that can be submersible in semi-solid and liquid materials and / or whose open circuit end can be applied to solid materials. In this way, it is possible to carry out much simpler and faster measurement processes. Open circuit sensors are mainly of two types: coaxial or rectangular guide [Stuchly1980], [Teodoridis1985]. The open circuit coaxial sensor is the most popular. It allows measurements of dielectric properties of a wide variety of solid, semi-solid and liquid materials to be carried out faster and in a much wider frequency range than the rectangular sensor, since the latter requires several sizes of its


    structure (with the respective measurement system calibration processes) to cover a wide frequency spectrum. Although the coaxial sensor in open circuit has a clear advantage in terms of bandwidth, the rectangular waveguide sensor in open circuit allows the characterization of anisotropic materials [Chang1996].
    Description of the invention
    The present invention focuses on the electromagnetic characterization of non-material
    '' '
    magnetic (  j1 j 0). In addition, the materials to be characterized are considered
    They are purely dielectric and of two types: isotropic or anisotropic. The properties
    '' '
    Dielectric (  j) of an isotropic material are identical in all directions of
    the axes of the coordinate system (x, y, z). However, this is not the case for a
    '' '
    anisotropic material. For an anisotropic material, the dielectric properties (  j)
    they are different according to the orientation in the coordinate system (x, y, z) and are represented by a tensor or matrix. An anisotropic dielectric material has a permittivity tensor with a diagonal matrix in the coordinates (x, y, z) as follows:
    Dx   xx 00Ex   
    D  0  0 E [1]
     and  yy  and   
    D 00  E
     z  zz  z 
    where D and E are, respectively, the electric displacement tensor and the
    electric field.  xx,  yy and  zz are the main components of complex permittivity.
    An anisotropic material can be divided into two types: uniaxial or biaxial. A biaxial anisotropic material has the three different permittivity components of the diagonal of the tensor [1], while a uniaxial anisotropic material is defined as having two of the three components of the permittivity of the tensor [1] equal. In the case of a uniaxial anisotropic material, the axis of the different permittivity is called the optical axis. As an example, if we assume that x is the optical axis of a uniaxial anisotropic material, then the principal components of the complex permittivity of the tensor [1] can be written from the
    '' '' ''
    following way:  xx  //  r //  j r // y  yy  zz   r j r where // y 
    they define, respectively, the parallel component and the orthogonal component to the optical axis.


    The present invention proposes to cover the need to characterize isotropic or anisotropic dielectric materials in a wide range of RF / microwave frequencies by means of a sensor. The components of complex permittivity of the isotropic () or anisotropic material
    ( xx,  yy,  zz) are determined from simple measurements in reflection with a sensor in
    microstrip open circuit, coplanar or an alternative configuration presented in this invention. These sensors have the same advantages as the open circuit coaxial sensor [Stuchly1980], since they can be used in non-destructive reflection methods, allowing simple and rapid measurements in vivo and in situ of a wide variety of materials (solid, semi-solid and liquids) The main difference between the coaxial sensor and the sensors of the present invention is in its configuration. The coaxial sensor has an axial configuration, while the proposed sensors have planar structures that make them suitable for characterizing anisotropic materials and covering a higher frequency bandwidth. Although the rectangular sensor allows the characterization of anisotropic materials [Chang1996], the sensors proposed in the present invention do not need several structure sizes to cover a wide range of frequencies. In addition, given the small contact surface exhibited by the sensors of the present invention at their end, they require only a small amount of material to be characterized, which makes them interesting when the material to be characterized is scarce.
    In this context, the present invention proposes new techniques of non-destructive measures to characterize isotropic and, in addition, anisotropic materials, in a wide range of RF / microwave frequencies by means of an open circuit sensor of microtire type (microstrip), coplanar or with a alternative configuration These sensors improve the characterization methods in open circuits based on coaxial or rectangular guides. The structures of the present invention can be used in non-resonant and non-destructive methods and, therefore, allow them to perform in vivo and in situ measurements of a wide variety of isotropic or anisotropic materials (solids, semi-solids and liquids) in a wide frequency range In addition, the use of any sensor of the present invention can be of great interest when the material to be characterized is scarce, since the end of any of these sensors requires a small contact surface.


    In the most common case of an isotropic solid material, the technique proposed to achieve the
    '' '
    complex permittivity (  j) consists in measuring the complex reflection coefficient (S11) of the sensor (microstrip, coplanar or alternative configuration) in contact with the surface of the material to be characterized by a vector network analyzer. The complex reflection coefficient (S11) describes the amplitude and phase of the reflected wave
    '' '
    Regarding the incident wave. The complex permittivity (  j) is obtained based on the measurements of the complex reflection coefficient (S11) and an inverse method, which is based on a model that analyzes the sensor end (microstrip, coplanar or alternative configuration) applied to a material. Given the lack of a precise model in the literature of this type of discontinuity with the proposed sensors, an original and versatile modeling technique based on fuzzy logic is proposed [J. W. Bandler,
    M. A. Ismail, J. E. Rayas-Sánchez, and Q. J. Zhang, “Neuromodeling of microwave circuits exploiting space-mapping technology”, IEEE Transactions on Microwave Theory and Techniques, vol. 47, pp. 2417-2427, December 1999 (Bandler1999)], [E. B. Rahouyi, J. Hinojosa, and J. Garrigós, “Neuro-fuzzy modeling techniques for microwave components”, IEEE Microwave and Wireless Components Letters, vol. 16, pp. 72-74, February 2006 (Hinojosa2006)]. The technique combines in different ways thick models (few precise) with the precision of fine models (electromagnetic simulator) by neuro-fuzzy inference systems [J. S. Jang, “ANFIS: Adaptive-network-based fuzzy inference system,” IEEE Transactions on Systems, Man, and Cybernetics, vol. 23, pp. 665-685, 1993 (Jang1993)]. In this way, models with the following advantages are achieved: high precision, wide range of input and frequency parameters and computational efficiency. In addition, given its versatility, it can be applied to the different sensors of the present invention, to various states and conditions of the material to be characterized and to effects derived from the measurements (radiation, errors in modules and phases, etc.) that may arise.
    The proposed microstrip, coplanar and alternative configurations sensors are suitable for characterizing anisotropic materials, due to their planar type structures. The electric and magnetic fields in these sensors are quasi orthogonal and are confined between the conductive strip and the mass. Thus, the electromagnetic field in these sensors is defined in two axes of a three-coordinate system (x, y, z), which facilitates the characterization technique to extract the complex permittivities of the tensor from the anisotropic material. The characteristics of an anisotropic solid material are obtained by turning


    this one properly 90º and measuring the complex reflection coefficient (S11) of the sensor in contact with the surface as many times as necessary to extract the properties of its tensioner. The complex permittivities of the tensioner are determined from the previous extraction method for isotropic materials and a linear combination of the results obtained from the different measurements in reflection. For a non-resonant characterization technique, these sensors have great potential, since they can be applied in a wide range of frequencies, to a wide variety of isotropic or anisotropic materials in solid, semi-solid or liquid states.
    Thus, the invention consists of a non-destructive technique for measuring the electromagnetic properties of isotropic or anisotropic dielectric materials, in a wide range of RF / microwave frequencies, by means of an open circuit sensor of the microstrip, coplanar type or with an alternative configuration. In the case of an isotropic solid material under test, the experimental technique measures the complex reflection coefficient of the sensor (microstrip, coplanar or alternative configuration) in contact with its surface as a function of frequency. The complex permittivity of an isotropic material under test is extracted from the measurements of the reflection coefficient as a function of frequency and of a model, relative to the discontinuity of the sensor in contact with the material under test. To achieve a computationally efficient and precise model, an original neuro-fuzzy modeling technique is applied. On the other hand, microstrip sensor structures, coplanar
    or alternative configuration are characterized by having perpendicular electric and magnetic fields confined between the conductive strip and the mass, these being defined in a plane of a system of three coordinates (x, y, z) and, therefore, suitable for characterizing anisotropic materials . In the case of a uniaxial anisotropic material under test, the two components of complex permittivity ( //, ) of the tensor diagonal
    they are extracted from two measurements in reflection with the sensor, made in the parallel plane and the orthogonal plane of the material. Similarly, three measurements in reflection with the sensor are necessary to obtain the three components of complex permittivity ( xx,  yy,  zz)
    of a biaxial anisotropic material under test, rotating it according to the three axes of the coordinate systems (x, y, z). The complex permittivities of the tensor (uniaxial, biaxial) are determined from the extraction method for isotropic materials and a linear combination of the results obtained from the different measures in reflection. These sensors may be of interest for measurements in situ and in vivo over a wide frequency range, since they can be applied not only to solid materials, but also


    to semi-solid and liquid materials. In addition, they require a small amount of material, since the tip of these sensors has a small contact surface.
    The objective of the present invention is based on a technique of measurements in reflection
    5 for the electromagnetic characterization of isotropic or anisotropic materials by means of amicrostrip, coplanar or alternative configuration sensor. The mainInnovations of the sensors of the invention are the following possibilities and skills:extraction of the complex permittivity of a wide variety of solid isotropic materials,semi-solids or liquids; extraction of the complex permittivity components of the tensioner
    10 dielectric of a wide variety of solid, semi-solid or liquid anisotropic materials; partial or complete submersion of the sensors in semi-solid and also liquid materials; use in non-destructive reflection methods; realization of measurements in situ and in vivo and measurements in a wide range of RF / microwave frequencies.
    A basic embodiment of the system of the invention is defined in claim 1. A basic embodiment of the method of the invention is defined in claim 18. The dependent claims define additional features of the invention.
    Description of the figures
    20 Figure 1 shows the system of measurements in reflection for the electromagnetic characterization of isotropic or anisotropic materials with a sensor (S1) with open circuit termination (microstrip, coplanar or alternative configuration).
    25 Figures 2A-2E show three-dimensional representations of different conditioning of solid materials with cubic shape and unknown properties that could be used under test. -Figure 2A shows an unknown material (M) to be characterized with properties
    unknown 30 - Figure 2B shows an unknown material (M) deposited on a material with known properties, that is, a known material (Mc). -Figure 2C shows an unknown material (M) deposited on a conductive material (Mcond). - Figure 2D shows an unknown material (M) deposited on two layers comprising a known material (Mc) and a conductive material (Mcond).


    - Figure 2E shows a known material (Mc) deposited on two layers comprising an unknown material (M) and a conductive material (Mcond).
    Figure 3A shows a microstrip sensor with a three-dimensional structure.
    Figure 3B shows a cross-sectional view and detail of the electromagnetic field of the quasi-TEM fundamental mode. The propagation medium of the microstrip structure is not homogeneous, since the electric and magnetic fields are distributed in the permittivity substrate  r and in the air.
    Figure 4A shows a coplanar sensor with a three-dimensional structure.
    Figure 4B shows a cross-sectional view and detail of the electromagnetic field of the quasi-TEM fundamental mode. The propagation medium of the coplanar structure is not homogeneous, since the electric and magnetic fields are distributed in the permittivity substrate  and in the air.
    r
    Figures 5A, 5B show a general modeling method with input ofprior knowledge (ECP-MANFIS).-Figure 5A shows a training of the ECP-MANFIS method.-Figure 5B shows a resulting ECP-MANFIS model.
    Figures 6A, 6B show a classical generalized modeling method (C-MANFIS)used to obtain the thick model of figures 5A, 5B.-Figure 6A shows a training of the C-MANFIS method.-Figure 6B shows a resulting C-MANFIS model.
    Figures 7A, 7B show a general modeling method with differences inExits (DS-MANFIS) used to subtract the side effects derived frommeasurements in the ECP-MANFIS model.-Figure 7A shows a training of the DS-MANFIS method.-Figure 7B shows a resulting DS-MANFIS model.


    Figures 8A, 8B show results as a function of the frequency of complex permittivity obtained with the microstrip sensor and the extraction technique presented in this invention for the isotropic material (M) of Table 2.
    '
    - Figure 8A shows the real permittivity ().
    r
    - Figure 8B shows the angle of losses (tg).
    Figure 9A, 9B show results as a function of the frequency of the complex permittivities of the dielectric tensioner obtained with the microstrip sensor and the extraction technique presented in this invention for the uniaxic anisotropic material (M) of Table 2.
    ''
    - Figure 9A shows real permittivities: parallel ( r //) and orthogonal ( r, ).
    - Figure 9B shows loss angles: parallel (tg //) and orthogonal (tg).
    Figure 10 shows a cross-sectional view of an alternative configuration to the sensormicrostrip
    Figure 11 shows a cross-sectional view of an alternative configuration to the sensorcoplanar
    Figure 12 shows the measurement system in reflection for characterizationElectromagnetic of isotropic or anisotropic materials with two sensors (S1, S2) withterminations in open circuits and oriented at 90º according to two axes of the systemcoordinates (x, y, z).
    Figure 13 shows the measurement system in reflection for characterizationElectromagnetic of isotropic or anisotropic materials with three sensors (S1, S2, S3) withterminations in open circuits and oriented at 90º according to the three axes of the systemcoordinates (x, y, z).
    The numerical references of the elements of the invention are indicated below:Complex reflection coefficient (S11, S11,1, S11,2)Reference close-up (P1)Second reference plane (P2)Measuring equipment (EM)First sensor (S1)


    Second sensor (S2)Third sensor (S3)First transmission guide (G1)Second transmission guide (G2)Third transmission guide (G3)First transition (T1)Second transition (T2)Third transition (T3)Fourth transition (T4)Fifth transition (T5)Sixth transition (S6)Seventh transition (T7)First data guide (GD1)Second data guide (GD2)Screen (P)External Processing Unit (UPE)Storage media (MA)Unknown material (M)Known Material (Mc)Conductive material (Mcond)Width (a) of unknown material (M)Height (b) of unknown material (M)Thickness (e) of unknown material (M)Known thickness (ec) of known material (Mc)Conductive thickness (econd) of the conductive material (Mcond)Input vector (X, XM, XME)Prior Knowledge Entry (ECP-MANFIS)Output vectors (YMF, YMG, YECP-MANFIS YC-MANFIS, YME, YDS-MANFIS)Exit vector of the fine model (YMF)Output vector of the thick model (YMG)Standard material output vector (YME)Exit vector of unknown material under test (Y)Fine Model (MF)Thick Model (MG)
    '
    Real permissibility ( r)


    Loss Angle (tg)
    '
    Actual permissibility of the parallel component ( r //)
    '
    Actual permissibility of the orthogonal component ( r ) Loss angles for the parallel component (tg //)
    5 Loss angles for the orthogonal component (tg) Encapsulation surfaces (SP1, SP2, SP3, SP4) Encapsulation surface thicknesses (tS1, tS2, tS3, tS4) First substrate (Su1) Second substrate (Su2) 10 Width of first substrate (WSu1) Length of first substrate (LSu1) Thickness of first substrate (h1) Width of second substrate (WSu2) Thickness of second substrate (h2) 15 First side (1) of first substrate (Su1) Second side (2) of the first substrate (Su1) Third face (3) of the second substrate (Su2) Fourth face (4) of the second substrate (Su2) Conductive strip (TC) 20 Strip width (WTC), Strip length (LTC) Strip thickness (tTC) Conductor plane (PC) Conductor plane width (WPC) 25 Conductor plane length (LPC) Plane thickness (tPC) Conductive strips (FC1, FC2) Strip widths (D1, D2) Strip lengths (LD1, LD2) 30 Strip thicknesses (t1, t2) Distances (R1, R2)


    Detailed description of the invention
    Figure 1 schematically shows the measurement system in reflection for the electromagnetic characterization of materials with a first sensor (S1) with open circuit termination. The first sensor (S1) can be microstrip, coplanar or an alternative configuration. The first sensor (S1) is connected to an RF / microwave measuring device (EM) (vector network analyzer) by means of a first transmission guide (G1) and two transitions (T1, T2). A first transition (T1) makes the transition between the first sensor (S1) and a first transmission guide (G1), while a second transition (T2) makes the transition between the first transmission guide (G1) and the transmission equipment. Measures (EM) RF / microwave. Depending on the type of unknown material (M) to be characterized, the end of the first sensor (S1) will be applied in open circuit on the surface of a solid material, or the first sensor (S1) will be partially or completely submerged when it is a semi-solid or liquid material. In the measurement system of Figure 1, an unknown material (M) to be characterized as solid has been considered, with a configuration like that of Figure 2A. In Figure 2A, the unknown material (M) has an orthopedic shape: its dimensions in the x-width, y-height and z-thickness coordinates are, respectively, width (a), height (b) and thickness (e) - the height (b) is not shown in figure 1 due to the two-dimensional representation of said figure. The RF / microwave measurement equipment (EM) is connected by a first data guide (GD1) to an external processing unit (UPE) and the external processing unit (UPE) to a display
    (P) visualization using a second data guide (GD2). The RF / microwave measurement equipment (EM) performs the measurements in reflection of the first sensor (S1) as a function of frequency and with respect to the first reference plane (P1). The measurement data in reflection of the first sensor (S1) is stored in the RF / microwave measurement equipment (EM) and / or in the external processing unit (UPE). The complex permittivity of the unknown material (M) is extracted from the processing of the measurement data in reflection of the first sensor (S1) by the external processing unit (UPE); The external processing unit (UPE) can also be used to carry out the control and calibration processes of the measurement system. The results obtained can be displayed on the screen (P).
    Figures 2A-2E represent, in three dimensions, some conditioning of a solid unknown material (M) that could be used in the technique of measurements in reflection


    of the system of Figure 1 or in an alternative configuration of the system as illustrated in Figures 12 and 13.
    In Figure 2A, only the unknown material (M) that has an orthopedic shape is shown.
    In Figures 2B and 2C, the unknown material (M) that has a thickness (e) is deposited, respectively, in a layer that has a known thickness (ec) of a known material (Mc) - it is called known material (Mc ) to one that has known properties - and in a layer that has a conductive thickness (econd) of a conductive material
    10 (Mcond).
    Figures 2D and 2E represent a conditioning of the unknown material (M) in a three layer configuration:
    In Figure 2D, the unknown material (M) is deposited on two layers of material: a layer that has a known thickness (ec) of a known material (Mc) and another layer that has a conductive thickness (econd) of a conductive material (Mcond).
    In Figure 2E, the known material (Mc) of known thickness (ec) is deposited on
    20 two layers of material: a layer that has a thickness (e) of an unknown material (M) and another layer that has a conductive thickness (econd) of a conductive material (Mcond).
    Figure 3A depicts the three-dimensional structure of a microstrip sensor of the invention. The microstrip sensor illustrated in Figure 3A comprises: a conductive strip (CT) having a strip width (WTC), a strip length (LTC) and a strip thickness (tTC); Y
    - a conductor plane (PC) having a conductor plane width (WPC), a length
    of conductive plane (LPC) and a thickness of conductive plane (tPC).
    30 The conductive strip (CT) and the conductive plane (PC) are separated by a first substrate
    '' '
    (Su1) dielectric (ε = ε  jε) having a first substrate length (LSu1) and a
    rr r
    thickness of first substrate (h1).
    Figure 3B shows the cross-sectional view of the microstrip sensor and detail of the electromagnetic field 35 for the quasi-TEM fundamental mode.


    The electromagnetic field lines in the transverse plane of the microstrip sensor for the quasi-TEM fundamental propagation mode are distributed on the first substrate (Su1) and in the air. Due to the effect of the first substrate (Su1) and the microstrip sensor structure, the electromagnetic field is mainly confined between the conductive strip (CT) and the conductive plane (PC). Therefore, the electric field lines, represented with a continuous line, are mainly oriented in the vertical axis (0, y), while the magnetic field lines, represented in dashed lines, perpendicular to the electric field lines, are oriented on the horizontal axis (0, x).
    Figures 4A and 4B represent the three-dimensional structure (Figure 4A) and the distribution (Figure 4B) of the electromagnetic field (quasi-TEM fundamental propagation mode) in the transverse plane of the coplanar sensor of Figure 4A. The coplanar sensor illustrated in Figure 4A comprises: a conductive strip (TC) having a strip width (WTC), a strip length (LTC) and
    a strip thickness (tTC); -two conductive stripes (FC1, FC2) that have strip widths (D1, D2), lengths
    of strip (LD1, LD2), strip thicknesses (t1, t2), separated from the conductive strip (CT)
    distances (R1, R2).
    The conductive strip (CT) and the two conductive strips (FC1, FC2) are deposited in a
    '' '
    first substrate (Su1) dielectric (   j) having a length of first substrate
    rr r
    (LSu1) and a thickness of first substrate (h1).The electromagnetic field lines of the quasi-TEM fundamental propagation mode aredistributed on the first substrate (Su1) and in the air as illustrated in Figure 4B. Due to theeffect of the substrate and the structure of the coplanar sensor, the electromagnetic field ismainly confined between the conductive strip (CT) and the two conductive strips (FC1,FC2). Therefore, as illustrated in Figure 4B, the electric field lines,represented with a continuous line, they are mainly oriented on the horizontal axis (0, x),while the magnetic field lines, represented in dashed line,perpendicular to the electric field lines, they are oriented on the vertical axis (0, y).
    Figures 5A, 5B, 6A, 6B, 7A, 7B represent three neuro-blurred modeling methodsused in the extraction technique of the invention to achieve complex permittivity


    depending on the frequency of an unknown material (M) under test. In the measurement system of Figure 1, a discontinuity appears between the first sensor (S1) and the unknown material (M) under test. Figures 5A, 5B, 6A, 6B are theoretically responsible for modeling the discontinuity between the first sensor (S1) and the unknown material (M) to be characterized, while Figures 7A, 7B take into account effects derived from the measurements (radiation , errors in modules and phases, etc.) that could arise and that cannot be considered in the theoretical model. In these methods, the fine model (MF) is obtained by an electromagnetic simulator and the thick model (MG) is achieved by the classical method (C-MANFIS) of figures 6A, 6B. MANFIS is an extension of ANFIS (Adaptive-Network-based Fuzzy Inference System) [Jang1993] to produce multiple outputs in the model. ANFIS is a five-layer forward propagation network that implements neuro-fuzzy rules to produce a single real-type output response based on several inputs. MANFIS is combined in different ways with fine models (figures 6A, 6B), thin and thick (figures 5A, 5B) and with measurements (figures 7A, 7B). In Figures 5A, 5B, 6A, 6B, 7A, 7B (X), (XME) and (XM) are input vectors, while (YMF), (YMG), (YME), (Y) and ( Y) represent output vectors. The purpose of each modeling method is to train MANFIS so that its output vector fits the corresponding output vector: (YMF) for Figures 5A and 6A, and (Y) for Figure 7A. As a result of the training process, the resulting models of Figures 5B, 6B and 7B are achieved.
    Figures 5A, 5B represent, by flowcharts, the generalized modeling method with Prior Knowledge Entry (ECP-MANFIS) used in this invention, to obtain the discontinuity model between the first sensor (S1) and the unknown material (M) to characterize the measurement system in reflection represented in Figure 1. (X) represents the input vector and (YMF, YMG YECP-MANFIS) represent output vectors. In the method of Figures 5A and 5B, the fine model (MF) is obtained by an electromagnetic simulator and the thick model (MG) is achieved by the classical method (C-MANFIS) of Figures 6A and 6B. Figure 5A represents the training process of MANFIS2. The objective is to train MANFIS2 so that its output vector (YECP-MANFIS) fits the output vector of the fine model (YMF) based on the input vector (X). Once trained, the resulting theoretical model of Figure 5B is achieved, which is used to extract the theoretical complex permittivity as a function of the frequency of an unknown material (M) under test with the system represented in Figure 1.


    Figures 6A, 6B represent, by flowcharts, the method of Generalized Classic Modeling (C-MANFIS) used in this invention to obtain the thick model of Figures 5A, 5B. (X) represents the input vector and (YMF, YC-MANFIS) represent output vectors. In the method of Figures 6A and 6B, the fine model (MF) is obtained by an electromagnetic simulator. Figure 6A represents the training process of MANFIS1. The objective is to train MANFIS1 so that its output vector (YC-MANFIS) fits the output vector of the fine model (YMF) based on the input vector (X). Once trained, the theoretical model resulting from Figure 6B is achieved, which is used as a thick model in the generalized modeling method with prior knowledge input (ECP-MANFIS).
    Figures 7A, 7B represent, by flowcharts, the generalized modeling method with Output Differences (DS-MANFIS) used in this invention to take into account the effects derived from the experimental measurements taken with the reflection measurement system represented. in figure 1 (reproducibility errors, module and phase errors, etc.) that cannot be considered in the theoretical model of figures 5A, 5B. (XME) represents the input vector and (YME, YECP-MANFIS, YDS-MANFIS) represent output vectors. In the method of Figures 7A and 7B, measurements of Standard Materials with known properties are used. Figure 7A represents the training process of MANFIS3. The objective is to train MANFIS3 so that its output vector (YDS-MANFIS) fits the output vector corresponding to the difference between (YME) and (YECP-MANFIS) based on the input vector (XME). Once trained, the resulting model of Figure 7B is achieved, which is used to extract the experimental complex permittivity as a function of the frequency of an unknown material (M) under test in the system of Figure 1.
    Figures 8A, 8B represent the results as a function of the frequency of the complex permittivity of an unknown isotropic solid (M) material under test. These results were obtained from electromagnetic simulations of a microstrip sensor and an unknown (M) isotropic material under test. The electrical properties of the unknown (M) isotropic material under test are included in Table 2. The results were obtained from the extraction technique of Figure 5B. Figure 8A shows the
    '
    results of the actual permittivity () of the unknown material (M) isotropic under test,
    r
    while Figure 8B represents the results of the loss angle (tg).


    Figures 9A, 9B represent the results as a function of the frequency of the complex permittivity of an unknown anisotropic solid (M) material under test. These results were obtained from electromagnetic simulations of a microstrip sensor and an unknown (M) anisotropic material under test. The electrical properties of the unknown anisotropic material (M) under test are included in Table 2. The results were obtained from the extraction technique of Figure 5B. Figure 9A shows the
    '
    results of the actual permittivity of the parallel component ( r //, in continuous line) and the
    '
    actual permittivity of the orthogonal component ( r , in dashed line) of the material
    unknown (M) anisotropic under test, while Figure 9B represents the results of the loss angles for the parallel component (tg // in a continuous line) and the orthogonal component (tg in a broken line).
    Figure 10 shows a cross-sectional view of an alternative configuration to the microstrip sensor illustrated in Figure 3A.
    Figure 11 shows a cross-sectional view of an alternative configuration to the coplanar sensor illustrated in Figure 4A.
    The alternative configurations of Figures 10 and 11 are encapsulated by a rectangular structure formed by four surfaces (SP1, SP2, SP3, SP4) with thicknesses (tS1, tS2, tS3, tS4). The encapsulated structures shown in Figures 10 and 11 are filled with
    '' '' ''
    two substrates (Su1, Su2) dielectric ( r1  r1  j r1) and ( r2  r2  j r2). The substrates (Su1) and / or (Su2) may be air. The substrates (Su1, Su2) can also be the same substrate. The surfaces (SP1, SP2, SP3, SP4) are not necessarily all conductive. Other alternative embodiments comprise different combinations of structures, eliminating one surface or several surfaces (SP1, SP2, SP3, SP4).
    Figure 12 illustrates an alternative configuration to the measurement system in reflection of Figure 1. RF / microwave measurement equipment (EM) (vector network analyzers) usually have two independent output ports. The measuring equipment (EM) in Figure 12 has two ports. A third transition (T3) makes the transition between the second sensor (S2) and the second transmission guide (G2), while a fourth transition (T4) makes the transition between the second transmission guide (G2) and the transmission equipment.


    Measures (EM) RF / microwave. Thus, from the measurement system of Figure 12 with two sensors (S1, S2), for example microstrip, oriented at 90 ° according to two axes of the coordinate system (x, y, z), it is possible to simultaneously perform the two measures in reflection of unknown (M) uniaxial anisotropic materials in a wide range of
    5 RF / microwave frequencies. A combination of different sensors (S1, S2) (microstrip, coplanar, alternative configurations) can also be applied to the measurement system of Figure 12 to achieve the same purpose.
    Figure 13 illustrates an alternative configuration to the measurement systems in reflection of
    10 Figures 1 and 12. The RF / microwave measuring devices (EM) (vector network analyzers) can have more than two independent output ports. The measuring device (EM) in Figure 13 has four ports. A fifth transition (T5) makes the transition between the third sensor (S3) and the third transmission guide (G3), while a sixth transition (T6) makes the transition between the third transmission guide (G3) and the
    15 measuring equipment (EM) RF / microwave. Thus, from the measurement system of Figure 13 with three sensors (S1, S2, S3), for example microstrip, oriented at 90 ° according to the three axes of the coordinate system (x, y, z), it is possible simultaneously perform the three measurements in reflection of unknown (M) anisotropic materials with three components of complex permittivity ( xx,  yy,  zz) of the tensor diagonal [1], over a wide range
    20 RF / microwave frequencies. A combination of different sensors (S1, S2, S3) (microstrip, coplanar, alternative configurations) can also be applied to the measurement system of Figure 13 to achieve the same purpose.
    Table 1 includes the dimensions and characteristics of the microstrip sensor of Figure 3A in an open circuit used to illustrate the operation of the invention.
    WTC (mm) WPC (mm)LTC (mm)LPC (mm)
    0.6 61010
    LSU1 (mm) tTC (mm)tPC (mm)h1 (mm)
    10 0.01750.01750.635
    r tg
    9.8 0.001
    TABLE 1


    Table 2 contains the dimensions and properties of two solid materials under test used to illustrate the operation of this invention: one is an isotropic material and the other a uniaxial anisotropic material. The properties of these materials were considered constant depending on the frequency during the simulations.
    a-width (mm) b-height (mm)e-thickness (mm)
    101010
    (M) isotropic (M) uniaxial anisotropic
    8.5 'r  and tg = 0.007 9.5, // 'r, 0.0045tg // , 8.5,' r  , 0.0035tg 
    TABLE 2
    10 Table 3 includes the ranges of complex permittivity and frequencies used to obtain the fine model data and thus train (figures 5A, 6A) and generate the C-MANFIS models (figure 6B) and ECP-MANFIS (figure 5B ). In other words, table 3 collects ranges of simulated parameters by means of an electromagnetic simulator and applied to a microstrip sensor to train and generate the ECP-MANFIS models of figures 5A,
    15 5B and C-MANFIS of Figures 6A, 6B.
    Parameter Minimum valueMaximum valueHe passed
    Real permissiveness ('r) one12one
    Loss angle (tg) 00.010.002
    Frequency in GHz (f) 0.01100.1
    TABLE 3
    20 Table 4 shows the minimum, average and maximum relative errors, in the frequency range between 0.01GHz and 10GHz, due to the extraction method proposed in the
    '
    invention to achieve the real permittivity () and the angle of losses (tg) of the material
    r
    unknown (M) isotropic of table 2 under test.


    Parameter Relative Error (%)
    Minimum Means, mediumMaximum
    Real permissiveness ('r) 0.210-30.11.5
    Loss angle (tg) 0.065.532.6
    TABLE 4
    5 Table 5 shows the minimum, average and maximum relative errors, in the frequency range between 0.01 GHz and 10 GHz, which are given in the extraction method proposed in the invention to achieve the components of the tension permittivity of the unknown material
    (M) uniaxial anisotropic of table 2 under test.
    Parameter Relative Error (%)
    Minimum Means, mediumMaximum
    Real orthogonal permittivity ('r ) 2.83.24.2
    Orthogonal loss angle (tg) 0.0222.9154
    Real parallel permittivity ('r // ) 1.42.94.4
    Parallel loss angle (tg //) 0.4249.5294
    TABLE 5
    Figure 1 schematically shows the measurement system based on reflection measurements for the electromagnetic characterization of materials. The unknown material 15 (M) to be characterized can have any shape, although it requires a sufficiently flat, wide and high contact surface to be able to apply the tip of the first sensor (S1). . The RF / microwave measurement equipment (EM) performs the reflective measurements of the first sensor (S1) over a wide range of frequencies according to the data entered in the RF / microwave measurement equipment (EM) by the user. Before
    20 the measurements in reflection of the first sensor (S1), a calibration process of the measurement system is usually carried out in order to define a first reference plane (P1) of the measurements.


    In view of the above, the invention comprises a measurement technique in non-destructive reflection, based on the handling as illustrated in figure 1, of an open circuit sensor in microstrip technology (figures 3A, 3B), coplanar (figures 4A, 4B) or alternative configuration, to extract the electrical properties of isotropic or anisotropic materials (solids, semi-solids or liquids) in a wide range of RF / microwave frequencies.
    '' '
    To obtain the electrical properties ( rM  rM  jrM) of an unknown material
    (M) Under test with a measurement system such as that illustrated in Figure 1, an original extraction technique based on the processing of complex reflection coefficient data (S11), obtained in the first reference plane (P1) between the first sensor (S1) and the unknown material (M), together with the analysis of this discontinuity by means of a model. This model is difficult to achieve, due to the semi-open structure of the proposed sensors and the discontinuity between the first sensor (S1) and the material (M). In the first reference plane (P1), between the first sensor (S1) and the material (M) to be characterized, a complex reflection is produced due to the contribution of the quasi-TEM fundamental mode that propagates in the sensor (S1) and also for higher order purposes (radiation, higher modes, etc.). At present, no efficient and precise model of this discontinuity is available. Therefore, it is proposed to generate these models through a hybrid modeling technique based on fuzzy logic. This technique requires three modeling methods, represented in Figures 5A, 5B, 6A, 6B, 7A, 7B. These methods are versatile, since they can be applied to any sensor (S1, S2, S3) of the invention and to different shapes and conditions of unknown (M) solid, semi-solid or liquid material. Figure 2 represents some examples of conditioning of unknown solid material (M) that can be used in the illustrated characterization technique of Figure 1. The hybrid nature of the methods of Figures 5A, 5B, 7A, 7B requires less data of simulation to achieve the same precision as a classic approach (C-MANFIS, figures 6A, 6B) and improves the ability to generalize. Between the two hybrid modeling methods of Figures 5A, 5B, 6A, 6B, the ECP-MANFIS method of Figure 5A, 5B is the most suitable for achieving the precise theoretical model of discontinuity between the sensor (S1, S2, S3) and unknown material
    (M) to characterize, since in its fuzzy system (MANFIS2) a previous knowledge input (ECP) from the thick model is introduced, which facilitates learning and its ability to generalize. The hybrid method of modeling with output differences (DS-MANFIS) of Figures 7A, 7B is justified in the technique of extracting the


    electrical properties of a material (M) under test of the measurement system of Figure 1, since it is applied to subtract the effects derived from experimental measurements (reproducibility errors, module and phase errors, etc.) and which cannot Be considered in the theoretical model.
    In Figures 5A, 5B, 6A, 6B, 7A, 7B, MANFIS is an extension of ANFIS to produce multiple outputs in the model. ANFIS is an inference system that implements fuzzy rules to produce a single real-type output response based on several inputs [Jang1993]. MANFIS is combined in different ways with fine models (figures 6A, 6B), thin and thick (figures 5A, 5B) and also with measurements (figures 7A, 7B). The fine model is accurate, while the thick model is less accurate. The fine model and the thick model are obtained, respectively, by an electromagnetic simulator and the classical method (C-MANFIS) of figures 6A, 6B. The measurements (figures 7A, 7B) are made in standard materials with known properties as a function of frequency. In these methods illustrated in Figures 5A, 5B, 6A, 6B, 7A, 7B, (X, XME, XM) are input vectors, while (YMF, YMG, YME, Y) respectively represent the output vectors of the fine model, the thick model, the standard material and the measurements of the unknown material under test. The input vectors include the data of the discrete frequency, the module and the phase of the complex reflection coefficient (S11), obtained by electromagnetic simulations (X), measurements of standard materials (XME) and measurements of unknown materials (XM) in the first reference plane (P1) of the measurement system of Figure 1. The output vectors contain the complex permittivities
    '' '
    (   j) of the material under test corresponding to the fine model (YMF), thick model
    rr r (YMG), standard material (YME) and unknown material under test (Y). In the case of the C-MANFIS classic modeling method (Figures 6A, 6B), MANFIS1 is trained based on the input (X) and output (YMF) vectors. For the modeling method with ECP-MANFIS prior knowledge input (Figures 5A, 5B), the output of the thick model (YMG = YC-ANFIS) and (X) is used as the input vector and the output vector (YMF) to train MANFIS2. Finally, the DS-MANFIS modeling method (Figure 7A) makes the difference between the output vector (YME), obtained during the measurements of different standard materials, and the output vector of the ECP-MANFIS model to train MANFIS3 based on the input vector (XME).
    The number (i) of ANFIS included in MANFIS1, MANFIS2 and MANFIS3 is equal to the number of parameters of the output vector. Since all the modeling methods illustrated in the


    Figures 5A, 5B, 6A, 6B, 7A, 7B have the same output vector length, they will be
    '
    Two ANFIS inference systems are required: one for the real permittivity () and the other
    r
    ''
    for imaginary permittivity (). The objective of C-MANFIS modeling methods and
    r ECP-MANFIS, is to find the outputs (YMG = YC-MANFIS) and (YECP-MANFIS) of MANFIS1 and MANFIS2 as tight as possible to the theoretical complex permittivity (YMF) of the material (M) under test. In this way, a precise ECP-ANFIS theoretical model (figure 5B) (YECP-MANFIS  YMF) (figure 5A) is obtained and computationally efficient when a vector (X) is applied at the input. On the other hand, the DS-ANFIS method consists in obtaining an output of MANFIS3 adjusted to the difference between the output vectors (YME) and the ECP-MANFIS (YECP-MANFIS) model (Figure 7A). In this way, in the resulting model of figure 7B, the effects derived from the measurement process (reproducibility errors, module and phase errors, etc.) that cannot be taken into account in the theoretical modeling can be compensated (figure 5B ).
    To illustrate the operation of the sensors proposed in this invention, we present some results extracted from electromagnetic simulations of the microstrip sensor illustrated in Figures 3A, 3B, in open circuit, for two types of unknown (M) solid materials under test: isotropic and uniaxial anisotrope. The dimensions and characteristics of the open circuit microstrip sensor, as well as of the unknown materials (M) under test, are shown in Tables 1 and 2. The microstrip sensor illustrated in Figures 3A, 3B, with a first substrate (Su1 ) thickness (h1) and properties
    '' ''
    constants as a function of frequency ( = 9.8 and tg =  /  = 0.001), was optimized for
    r rr
    get a characteristic impedance Z = 50 . The properties of the materials
    C
    (isotropic and uniaxial anisotropic) under test (Table 2) were considered constant depending on the frequency in the simulations. The data of the fine model for training and generating the C-MANFIS and ECP-MANFIS models were obtained by means of a commercial simulator based on finite elements for the parameter ranges presented in Table 3. The electromagnetic simulations were performed in the frequency range between 0.01GHz and 10GHz. The C-MANFIS and ECP-MANFIS models were developed from functions of Gaussian-type belongings [Jang1993]. For each ANFIS entry, a number (ng) of membership functions were applied: 3 for C-MANFIS modeling and 4 for ECP-MANFIS modeling. The number of fuzzy rules for each ANFIS is equal to
    c  (ng) ng. Finally, 3 iterations were necessary to train each ANFIS.


    '' '
    The electrical properties (   j) of an unknown isotropic solid material (M)
    rr r under test are obtained by applying on its surface the end of the first sensor (S1) microstrip in open circuit and measuring (simulating in this illustrative example) the complex reflection parameter (S11) as a function of frequency, as in Figure 1 The frequency data, the module and the phase of the complex reflection coefficient (S11) are entered into a vector (X) and applied to the input of the ECP-ANFIS model (Figure 5B) that provides complex permittivity as a function of the frequency of the unknown material (M) under test. Figure 8 represents the results obtained. It can be seen that the complex permittivity coincides with that initially defined in the electromagnetic simulations
    '' ''
    (Table 2:  r  8.5, tg =  r /  r = 0.007). The properties of this material were not used (Table 3) to train and obtain the ECP-ANFIS model. Table 4 shows the minimum, average and maximum relative errors in the frequency range between 0.01GHz and
    '
    10GHz, due to the proposed extraction method to obtain the actual permittivity () and the
    r
    '' '
    loss angle (tg =  / ) of the unknown material (M) isotropic (Table 2) under
    rr
    proof. As expected with this non-resonant method of characterization of
    '
    material, the relative errors to obtain the real permittivity () are small (error
    r
    maximum lt; 1.5%) However, these are greater to extract the angle of losses (tg).
    '' '' ''
    The electrical properties ( r  r j r and  r //  r //  j r //) of the dielectric tensioner of an unknown material (M) solid uniaxial anisotropic under test, are obtained from two measurements of the reflection coefficient as a function of the frequency by means of the experimental system of figure 1. For the two measurements, the following was considered: -the configuration of figure 2A for the uniaxial anisotropic unknown material (M) ; -the configuration of Figure 3A for the microstrip sensor (S1); -that the unknown material (M) anisotropic has an optical axis in the axis (y). Thus, the first measurement of the complex reflection coefficient (S11,1) is obtained in the plane (x, y) of unknown material (M) uniaxial anisotropic under test. For the second measurement of the complex reflection coefficient (S11,2), where subscript 2 indicates the second measurement, the uniaxial anisotropic material (M) is rotated 90 ° around the axis (0) so that the microstrip sensor tip apply on the surface of the plane (x, z) of the latter.


    Another alternative to the previous procedure would be to rotate the first sensor (S1) 90º instead of the material (M). Entering the frequency data, the complex reflection coefficient of a first measurement (S11,1) and the complex reflection coefficient of a second measurement (S11,2) in two vectors (X1) and (X2) and applying them to the input of the ECP-ANFIS model (figure 5B), two complex permittivities of the unknown anisotropic material (M) are obtained
    '' '' ''
    uniaxial as a function of frequency: r1 r1  jr1 and  r2  r2  j r2. The first
    '' '
    complex permittivity (r1 r1  jr1) corresponds to orthogonal electrical properties
    '' '
    (r1 r r jr) of the dielectric tensor of the unknown material (M) solid uniaxial anisotropic under test, since the measurements of the reflection wave were made perpendicular to the optical axis (y) of unknown material (M) under test. The second
    '' '
    complex permittivity ( r2  r2  j r2) results in a complex effective permittivity
    '' '
    ( r2  ref  ref  j ref) as a result of rotating the material 90 ° around the axis (0, x)
    unknown (M) anisotropic. If the deformations of the fields are neglected due to the anisotropic behavior, this complex effective permittivity can be defined as follows:
     
    r // r
     ref  [2]
    In this way, complex parallel permittivity can be calculated from the measures of complex effective and orthogonal permittivities:
     r //  2 ref  r [3]
    Figures 9A and 9B represent the results obtained with the microstrip sensor (S1) for the uniaxial anisotropic material (M) of Table 2 under test by the procedure of the
    '' '
    invention. It can be seen that the electrical properties  r  r j r and
    '' '
     r //  r //  j r // of the dielectric tensioner match those initially defined in the ''
    Electromagnetic simulations listed in Table 2:  r //  9.5, tg //  0.0045,  r  8.5,
    tg  0.0035. The properties of this anisotropic material (M) were not used (Table 3) to train and obtain the ECP-MANFIS model. Table 5 shows the minimum, average and maximum relative errors in the frequency range between 0.01GHz and 10GHz, due to the


    Extraction method proposed to obtain the complex permittivity components of the tensor of the uniaxial anisotropic material (M) from Table 2 under test. In the same way as for the characterization of an isotropic material (M), this non-resonant method makes it possible to extract the real permittivities of the anisotropic material (M) accurately enough. As can be seen in Table 5, the relative errors for
    ''
    obtaining the real parts of the tensioner ( r //,  r ) of the uniaxial anisotropic material (M) under test are relatively small (maximum error <4.4%). These errors can be even smaller, training the proposed extraction technique based on fuzzy logic not only with isotropic materials (Table 3), but also with anisotropic materials.
    Figures 10 and 11 present alternative configurations to the microstrip sensors illustrated in Figure 3A and coplanar illustrated in Figure Figure 4A, respectively. Both alternative configurations are encapsulated by a rectangular structure formed by four encapsulation surfaces (SP1, SP2, SP3, SP4) with thicknesses (tS1, tS2, tS3,
    '' '
    tS4) and are filled with two substrates (Su1, Su2) of dielectrics ( r1  r1  j r1) and
    '' '
    ( r2  r2  j r2). The surfaces (SP1, SP2, SP3, SP4) are not necessarily all
    conductive Other variants to figures 10 and 11 would be to consider the different combinations of structures, eliminating one surface or several surfaces (SP1, SP2, SP3, SP4).
    In addition to different alternative sensor configurations, there may also be different alternative configurations of measurement systems. Thus, as alternatives to the measurement system of Figure 1, two alternative measurement systems are represented in Figures 12 and 13. RF / microwave measurement equipment (EM) (vector network analyzers) usually have two to four ports of independent outputs. Thus, from the measurement system of Figure 12 with two sensors (S1, S2), for example microstrip, oriented at 90 ° according to two axes of the coordinate system (x, y, z), it is possible to simultaneously perform the two measures in reflection of unknown materials
    (M) uniaxial anisotropes over a wide range of RF / microwave frequencies and extract the
    two components of complex permittivity ( r //,  r) of the tensioner. In the case of unknown (M) biaxial anisotropic materials with three components of complex permittivity ( xx,  yy,  zz) on the diagonal of the tensioner, the measurement system can be used
    Simultaneous three reflection coefficients of Figure 13 with three sensors (S1, S2, S3), oriented at 90º according to the three axes of the coordinate system (x, y, z). Due to the


    configuration of the electromagnetic fields of one and another sensor, you can alsoapply a microstrip combination (figure 3A) and coplanar (figure 4A) or a combination ofsome alternative microstrip configurations (figure 10) and coplanar (figure 11) to bothmeasurement systems of figures 12 and 13 to achieve the same purpose.
    As described, a first aspect of the invention relates to a system forElectromagnetic characterization of materials comprising:1a) a first sensor (S1) applied to an unknown material (M);1b) a measurement team (MS);1c) a first transmission guide (G1) connecting the first sensor (S1) with the equipment
    of measures (MS); 1d) a first transition (T1) configured to make a connection between the first sensor (S1) and the first transmission guide (G1); 1e) a second transition (T2) configured to make a connection between the first transmission guide (G1) and the measuring equipment (EM).
    According to other features of the invention:
    2. The measuring device (EM) can be configured to take measurements in reflection of the first sensor (S1) as a function of the frequency and with respect to a first reference plane (P1).
    3. The system may comprise: 3a) an external processing unit (UPE) configured to: 3a1) extract electromagnetic properties from unknown material (M) from
    measurement data in reflection of the first sensor (S1);3a2) control system operation;3a3) execute system calibration processes;
    3b) a first data guide (GD1) connecting the measuring equipment (EM) with the external processing unit (UPE); 3c) a display screen (P) configured to show results of the electromagnetic properties extracted from the unknown material (M); 3d) a second data guide (GD2) connecting the external processing unit (UPE) with the display screen (P).


    Four. The system may comprise: storage media (MA):4a) configured to collect measurement data from the first sensor (S1);4b) located in a location selected from: the measuring device (EM), the unit of
    external processing (UPE) and both.
    5. The first sensor (S1) may have an open circuit termination. The first sensor (S1) can be of a type selected from microstrip, coplanar and an alternative configuration.
    6. The first sensor (S1) may comprise:
    6a) a first substrate (Su1) having: 6a1) a first face (1); 6a2) a second face (2), opposite the first face (1); 6a3) a first thickness (h1) between the first face (1) and the second face (2);
    6b) a conductive strip (CT) on the first face (1); 6c) a conductive plane (PC) on the second side (2).
    7a) The first substrate (Su1) can have a first substrate width (WSu1) and a first substrate length (LSu1);
    7b) the conductive strip (TC) can have a strip width (WTC) and a strip length (LTC);
    7c) the conductor plane (PC) can have a conductor plane width (WPC) and a conductor plane length (LPC);
    7d) the strip width (WTC) may be smaller than the first substrate width (WSu1).
    In the alternative embodiment illustrated in Figure 3A:
    7e) the conductor plane width (WPC) can match the width of the first substrate
    (WSu1);
    7f) the strip length (LTC) and conductor plane length (LPC) can match the first substrate length (LSu1).
    8a) The conductive strip (CT) may have a strip thickness (tTC);
    8b) the conductive plane (PC) may have a conductive plane thickness (tPC).
    According to alternative embodiments:
    8c) the strip thickness (tTC) can match the conductive plane thickness (tPC);
    8d) the strip thickness (tTC) and the conductive plane thickness (tPC) may be less than the


    first thickness (h1).
    9. The first sensor (S1) may comprise:
    9a) a first substrate (Su1) having: 9a1) a first face (1) 9a2) a second face (2), opposite the first face (1); 9a3) a first thickness (h1) between the first face (1) and the second face (2);
    9b) a conductive strip (CT) on the first face (1); 9c) two conductive strips (FC1, FC2) on the first face (1), one on each side of the conductive strip (TC), separated from the conductive strip (TC) distances (R1, R2).
    10a) The first substrate (Su1) can have a first substrate width (WSu1) and a first substrate length (LSu1); 10b) the conductive strip (TC) may have a strip width (WTC) and a strip length (LTC); 10c) the two conductive stripes (FC1, FC2) may have strip widths (D1, D2) and
    strip lengths (LD1, LD2). According to alternative embodiments: 10d) a width formed by the width of the strip (WTC), plus the widths of the strip (D1,
    D2), plus the distances (R1, R2) may be less than the first substrate width
    (WSu1); 10e) the strip length (LTC) and the strip lengths (LD1, LD2) can coincide with the
    first substrate length (LSu1). 10f) the strip widths (D1, D2) may be the same; 10g) the distances (R1, R2) can be the same.
    11a) The conductive strip (CT) may have a strip thickness (tTC);11b) the conductive stripes (FC1, FC2) may have strip thicknesses (t1, t2).According to alternative embodiments:
    11c) the strip thickness (tTC) may coincide with the strip thicknesses (, t1 t2); 11d) strip thickness (tTC) and strip thicknesses (t1, t2) may be less than the first thickness (h1).
    12. The first sensor (S1) may comprise:


    12a) a second substrate (Su2): 12a1) stacked on the first substrate (Su1); 12b) an encapsulation (SP1, SP2, SP3, SP4) configured to wrap the first substrate (Su1) and the second substrate (Su2).
    13a) The second substrate (Su2): 13a1) may have a second substrate width (WSu2) coinciding with the
    width of the first substrate (WSu1) may comprise: 13a2) a third face (3); 13a3) a fourth face (4), opposite the third face (3); 13a4) a thickness of second substrate (h2) between the third face (3) and the fourth face
    (4); 13b) the encapsulation (SP1, SP2, SP3, SP4) has a rectangular cross section having: 13b1) a sum height of the thickness of the first substrate (h1) and the thickness of the second substrate (h2); and 13b2) an interior width coinciding with the width of the first substrate (WSu1);
    14. The system may comprise:14a) a second sensor (S2) applied to an unknown material (M);14b) a second transmission guide (G2) connecting the second sensor (S2) with the
    measurement equipment (MS); 14c) a third transition (T3) configured to make a connection between the second sensor (S2) and the second transmission guide (G2); 14d) a fourth transition (T4) configured to make a connection between the second transmission guide (G2) and the measuring equipment (EM);
    15a) The second sensor (S2) may be placed at 90 ° with respect to the first sensor (S1);
    15b) the first sensor (S1) and the second sensor (S2) can be: 15b1) oriented along two axes of a coordinate system (x, y, z), and 15b2) configured to obtain measurements simultaneously.
    In the embodiment illustrated in Figure 12, the first sensor (S1) and the second sensor (S2) are in a first reference plane (P1).
    16. The system may comprise:


    16a) a third sensor (S3) applied to an unknown material (M); 16b) a third transmission guide (G3) connecting the third sensor (S3) with the measuring equipment (EM); 16c) a fifth transition (T5) configured to make a connection between the third sensor (S3) and the third transmission guide (G3); 16d) a sixth transition (T6) configured to make a connection between the third transmission guide (G3) and the measuring equipment (EM);
    17a) The second sensor (S2) may be placed at 90 ° with respect to the first sensor (S1); 10 17b) the third sensor (S3) may be placed at 90 ° with respect to the first sensor (S1) and at 90 ° with respect to the second sensor (S2);
    17c) the first sensor (S1), the second sensor (S2) and the third sensor (S3) can be: 17c1) oriented along three axes of a coordinate system (x, y, z), and 17c2) configured to obtain Measures simultaneously in reflection.
    In the embodiment illustrated in Figure 13, the first sensor (S1) and the second sensor (S2) are in a first reference plane (P1) and the third sensor (S3) is in a second reference plane (P2) .
    A second aspect of the invention relates to a method for characterization.
    20 electromagnetic materials with the system described above. The method comprises: 18a) conditioning the unknown material (M) according to a selected configuration
    between one that includes:18a1) the unknown material (M);
    25 18a2) unknown material (M) deposited on a known material (Mc); 18a3) unknown material (M) deposited on a conductive material (Mcond); 18a4) the unknown material (M) deposited on two layers comprising a
    known material (Mc) and a conductive material (Mcond); 18a5) a known material (Mc) deposited on two layers comprising the unknown material (M) and a conductive material (Mcond).
    According to other characteristics, the method may include:
    35 19a) totally or partially immerse the sensor (S1, S2, S3) in an unknown material (M)


    semi-solid or liquid; 20a) take measurements in reflection in a domain selected between time domain and
    the dominance of frequency;21a) carry out the measurements in reflection according to the temperature;22a) perform measurements in situ or in vivo.
    权利要求:
    Claims (13)
    [1]
    1. System for electromagnetic characterization of materials characterized in that it comprises: 5 - a first sensor (S1) in open circuit, applied to an unknown material (M);
    - a measuring device (EM) configured to take measurements in reflection of the first sensor (S1) as a function of frequency and with respect to a first reference plane (P1);
    - a first transmission guide (G1) connecting the first sensor (S1) with the measuring device 10 (EM); - a first transition (T1) configured to make a connection between the first sensor (S1) and the first transmission guide (G1); - a second transition (T2) configured to make a connection between the first transmission guide (G1) and the measuring device (EM); 15 - an external processing unit (UPE) configured to: - extract electromagnetic properties of unknown material (M) from
    of measurement data in reflection of the first sensor (S1); - control system operation; - execute system calibration processes;
    20 - a first data guide (GD1) connecting the measuring equipment (EM) with the external processing unit (UPE); - a display screen (P) configured to show results of the electromagnetic properties extracted from the unknown material (M); - a second data guide (GD2) connecting the external processing unit 25 (UPE) with the display screen (P).
    [2]
    2. System for electromagnetic characterization of materials according to claim 1 characterized in that it comprises storage means (MA) configured to collect measurement data from the first sensor (S1) and located in a location
    30 selected from: the measuring equipment (EM), the external processing unit (UPE) and both.
    [3]
    3. System for electromagnetic characterization of materials according to any of the
    claims 1-2 characterized in that the first sensor (S1) comprises: - a first substrate (Su1) having a first face (1), a second face (2),

    opposite to the first face (1); a first thickness (h1) between the first face (1) and the second face (2), a width of first substrate (WSu1) and a length of first substrate (LSu1);
    - a conductive strip (TC) on the first face (1) having a strip width (WTC), a strip length (LTC) and a strip thickness (tTC);
    - a conductive plane (PC) on the second face (2) has a conductor plane width (WPC), a conductor plane length (LPC) and a conductor plane thickness (tPC);
    where the strip width (WTC) is smaller than the first substrate width (WSu1).
    [4]
    4. System for electromagnetic characterization of materials according to any of claims 1-2 characterized in that the first sensor (S1) comprises:
    - a first substrate (Su1) having a first face (1), a second face (2), opposite the first face (1); a first thickness (h1) between the first face (1) and the second face (2), a width of first substrate (WSu1); a length of first substrate (LSu1);
    - a conductive strip (TC) on the first face (1) having a strip width (WTC), a strip length (LTC) and a strip thickness (tTC); - two conductive stripes (FC1, FC2) on the first face (1), one on each side of the conductive strip (TC), separated from the conductive strip (TC) distances (R1, R2) and having strip widths (D1, D2), strip lengths (LD1, LD2) and strip thicknesses (t1, t 2).
    [5]
    5. System for electromagnetic characterization of materials according to any of claims 3 and 4 characterized in that the first sensor (S1) comprises:
    - a second substrate (Su2) stacked on the first substrate (Su1); - an encapsulation (SP1, SP2, SP3, SP4) configured to wrap the first substrate (Su1) and the second substrate (Su2).
    [6]
    6. System for electromagnetic characterization of materials according to claim 5
     characterized by:
    the second substrate (Su2) has a width of second substrate (WSu2) coinciding with the
    width of the first substrate (WSu1) and comprises: - a third face (3);

    - a fourth face (4), opposite the third face (3); - a thickness of second substrate (h2) between the third face (3) and the fourth face (4); The encapsulation (SP1, SP2, SP3, SP4) has a rectangular cross-section having: - a sum height of the thickness of the first substrate (h1) and the thickness of the second substrate (h2); and - an interior width coinciding with the width of the first substrate (WSu1);
    [7]
    7. System for electromagnetic characterization of materials according to any of claims 1-6 characterized in that it comprises: 10 - a second sensor (S2) applied to the unknown material (M); - a second transmission guide (G2) connecting the second sensor (S2) with the measuring device (EM); - a third transition (T3) configured to make a connection between the second sensor (S2) and the second transmission guide (G2);
    15 - a fourth transition (T4) configured to make a connection between the second transmission guide (G2) and the measuring equipment (EM);
    [8]
    8. System for electromagnetic characterization of materials according to claim 7 characterized in that the second sensor (S2) is placed at 90 ° with respect to the first
    20 sensor (S1) and the first sensor (S1) and the second sensor (S2) are oriented along two axes of a coordinate system (x, y, z), and configured to obtain measurements simultaneously.
    [9]
    9. System for electromagnetic characterization of materials according to any of the claims 7-8 characterized in that it comprises:
    - a third sensor (S3) applied to the unknown material (M); - a third transmission guide (G3) connecting the third sensor (S3) with the measuring device (EM); - a fifth transition (T5) configured to make a connection between the third sensor (S3) and the third transmission guide (G3); - a sixth transition (T6) configured to make a connection between the third transmission guide (G3) and the measuring equipment (EM);
    [10]
    10. System for electromagnetic characterization of materials according to claim 9, characterized in that the second sensor (S2) is placed at 90 ° with respect to the first

    sensor (S1); the third sensor (S3) is placed at 90º with respect to the first sensor (S1) and at 90ºwith respect to the second sensor (S2);where the first sensor (S1), the second sensor (S2) and the third sensor (S3) are orientedalong three axes of a coordinate system (x, y, z), and configured to obtain
    5 measurements simultaneously in reflection.
    [11]
    11. Method for electromagnetic characterization of materials with the system of any of claims 1-10 characterized in that it comprises:
    - condition the unknown material (M) according to a selected configuration
    10 between one comprising: - the unknown material (M), - the unknown material (M) deposited on a known material (Mc), - the unknown material (M) deposited on a conductive material (Mcond), - the unknown material (M) deposited on two layers comprising a
    15 known material (Mc) and a conductive material (Mcond), - a known material (Mc) deposited on two layers comprising the unknown material (M) and a conductive material (Mcond); - totally or partially immerse the sensor (S1, S2, S3) in an unknown material (M) semi-solid or liquid; 20 - make measurements in reflection in a domain selected between the time domain and the frequency domain.
    [12]
    12. Method for electromagnetic characterization of materials according to claim 11
    characterized in that it comprises carrying out the measurements in reflection according to the temperature.
    [13]
    13. Method for electromagnetic characterization of materials according to any of claims 11-12 characterized in that it comprises carrying out the measurements in situ or in vivo.

    FIG. one
    FIG. 2A

    FIG. 2B

    FIG. 2 C

    FIG. 2D
    FIG. 2E
    FIG. 3A

    FIG. 3B
    FIG. 4A

    FIG. 4B
    FIG. 5A
    FIG. 5B

    FIG. 6A
    FIG. 6B

    FIG. 7A
    FIG. 7B

    FIG. 8A
    FIG. 8B

    FIG. 9A
    FIG. 9B

    FIG. 10

    FIG. eleven
    FIG. 12

    FIG. 13
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