• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The invention employs a "feed-forward" method for canceling high-power signals reflected and transmitted by a device from which it is desired to obtain its electrical parameters before these signals enter the measuring instrument. In the measurement system for devices in a port, the power signal is divided into two branches: one that feeds directly to the device and another that cancels the reflected signal. The phase and magnitude of the cancellation signal is achieved by a device whose transmission can be controlled. Simultaneously, the device is also fed with a low power signal, necessary for the determination of the electrical parameters, and from the measuring instrument. This low power signal is not affected by the high power signal thanks to the cancellation made. The same circuit is used to measure the power transmitted in multiport devices. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2684570A1
    申请号:ES201730571
    申请日:2017-03-31
    公开日:2018-10-03
    发明作者:Carlos Collado Gomez；Jordi Mateu Mateu；Jose M. GONZÁLEZ ARBESÚ；Alberto HUELTES ESCOBAR；Marta GONZÁLEZ RODRÍGUEZ；David GARCÍA PASTOR；Rafael PEREA ROBLES
    申请人:Universitat Politecnica de Catalunya UPC；
    IPC主号:
    专利说明:

    D E S C R I P C I Ó N

    Method and system for measuring electrical parameters of radiofrequency devices under high power conditions.
     5
    SECTOR OF THE TECHNIQUE

    The present invention relates to methods and systems for measuring electrical parameters (dispersion parameters S, impedance parameters, admittance parameters, transmission parameters, etc.) used to characterize radio frequency devices 10 in working conditions with high power levels .

    BACKGROUND OF THE INVENTION

    There is a strong demand to increase the nominal power of the radiofrequency (RF) and microwave devices.

    The components and RF and microwave devices are measured and characterized with network parameters, such as dispersion parameters, impedance parameters, admittance parameters or transmission parameters. The magnitude and phase of these parameters are relevant and are measured using vector network analyzers (VNA, Vector Network Analyzer).

    Before measurement, the VNA must be carefully calibrated. Measurements with high power levels require complex calibration procedures and adequate calibration standards whose behavior must be previously characterized for each power.

    On the other hand, standard measurements using a VNA with high power levels require external components (high-power test-sets) to increase the power that feeds the device (KF Anderson, "A Survey of Techniques for Improving the Calibration of High-Power Network Analyzers ", Microwave Measurement Symposium (ARFTG), Dec. 2011, 10.1109 / ARFTG78.2011.6183878).

    The VNA must be protected to avoid exceeding the input power that would cause damage to the measuring instrument.

    The object of this invention is a measurement system architecture capable of feeding the device with high power levels using conventional calibration techniques and standards, and that preserves any damage to the measuring equipment due to the high input power.

    EXPLANATION OF THE INVENTION 10

    The present invention proposes a method for measuring the electrical parameters of a single port or multiport device in working conditions with high power signals. It is based on a “feed-forward” technique (JM Wetherington, MB Steer, “Robust Analog Canceller for High-Dynamic-Range Radio Frequency 15 Measurement,” IEEE Trans. Microw. Theory Tech., Vol. 60, no. 6, pp. 1709–1719, June 2012.) of the high power signals (HP, High Power) so that the high power signal is divided into two or more branches. One of them feeds the device to be measured (DUT, Device Under Test) by one port and the other or others are cancellation branches. twenty

    The phase and amplitude of the signals of the cancellation branches are modified by circuits governed by a control unit. Said cancellation signals are combined with the output signals (dispersed in reflection and transmission) of the device so that they are canceled preventing said signal 25 from entering the vector network analyzer (VNA) or suitable instrument to characterize its electrical parameters. At the same time the device is powered by low power signals to characterize its electrical parameters by means of a network analyzer or instrument suitable for this purpose. The calibration required to measure the electrical parameters is performed following the standard 30 procedure of low power calibration.

    The present invention is a method for measuring electrical parameters of a
    single port or multiport device under high power signals characterized from the measurement of impedance, admittance or transmission parameters.

    The invention is a measuring system for measuring the dispersion parameters of a single port or multiport device under high power signals characterized in that:
     The power of a signal source is divided into at least two or more branches. The signal of a path (DUT branch) is conditioned by a set of components (attenuators, amplifiers and isolators) and is connected to a port (connector) of the device under test. The remaining branches 10, the cancellation branches, are comprised of a set of components that adapt the power level and phase of the cancellation signals to the magnitude and phase of the signals dispersed in the DUT.
     The power reflected in the DUT input port and the power transmitted in the remaining DUT ports are combined with the cancellation signals through the use of combiners or splitters.
     The phase and attenuation of the cancellation signals are changed dynamically and in real time by circuits controlled by a control unit (processor) to cancel the reflected and transmitted power that is dispersed in the DUT. twenty
     The outputs of the power combiners are connected to a network analyzer including protective limiting circuits to prevent deterioration of the measuring equipment during the cancellation process.

    The signal source is conditioned with one or more attenuators and one or more 25 insulators. Specifically, the high power signal is generated with a signal source (SS, Signal Source). An external signal source network (SSN) provides the isolation required to prevent the reflected signals from feedback to the signal generator and, if required, cause the attenuation (Fig. 2) necessary to adjust the level of Signal strength to the following stages. 30

    The HP signal is divided into two or more branches using a power splitter (PS, Power Splitter, in Fig. 2). One is called “DUT BRANCH” and the other “CAN
    BRANCHES ”or“ cancellation branches ”. For a single port device there is only one cancellation branch, called “A-CAN BRANCH”. For a two-port device there are two cancellation branches, called "A-CAN BRANCH" and "B-CAN BRANCH". If necessary, dimmers are also placed on each branch to level the signal strength for the following stages. 5

    The DUT or "DUT BRANCH" branch may include one or more attenuators, one or more amplifiers and one or more isolators or circulators to prevent the reflected signals from feedback amplifier output. If necessary, the attenuators are also placed before the amplifier to adjust the power level 10 of the signal (Fig. 3).

    The DUT branch includes components that are capable of changing the phase and amplitude of the DUT branch signal instead of changing the amplitude and phase of the cancellation signals. fifteen

    One or more "cancellation branches" may include one or more attenuators, one or more amplifiers, one or more isolators or circulators and one or more vector modulators (VM), one or more variable attenuators and phase shifters, or one or more components with the mission of changing the amplitude and / or phase of the cancellation signals.

    The insulators would help to prevent the reflected signals from feeding back the amplifier, attenuators that can be placed before, between and / or after the vector modulator and the amplifiers that adjust the power levels of the signal (Figure 4). In the preferred embodiment (which will be described by way of example), the inputs of phase I and quadrature Q of the VM are power signals with controlled voltages to modify the attenuation and phase of the cancellation signals in real time. The resulting signal with the required phase and amplitude level will be amplified later. 30

    REFLECTED POWER

    The HP signal that feeds the DUT is connected to a directional device (DD, Directional Device, in Figure 5) that is capable of separating the high power (HP) signal incident to the DUT and the power reflected from the DUT. The power reflected in the input DUT is obtained by using a 3 dB coupler, a directional bridge or any reciprocal device that is capable of separating the indident power from that reflected in a device. In the case of a 90º hybrid (or any 3 dB directional coupler), one of the 3 dB outputs of the hybrid is connected to the DUT and the other 3 dB output at a load of 50 ohms. The power reflected by the DUT flows to the fourth port of the hybrid, which is the isolated port with respect to the input port to which the high power signal has been connected.

    A measurement system according to claim 3 characterized in that the signals dispersed in the DUT and the cancellation signals are combined using Wilkinson combiners.

    The scattered signals in the DUT and the cancellation signals, that is, the reflected HP signal and the A-CAN branch signal, are combined using 20 Wilkinson combiners (A-PC, A-Power Combiner), power combiners , 3 dB couplers, or any device that combines, in whole or in part, the two-port input signal and the resulting signal flows to a third port. The amplitude and phase of the A-CAN signal is modified in such a way that both signals are added with the same amplitude and in opposite phase so that they are canceled at the output of the combiner. 25 The combiner must be able to dissipate the power of both high power signals when they are canceled.

    Once the DUT signal and the cancellation signal are combined, the resulting signal is probed using a directional coupler and a power meter, a spectrum analyzer, or any device or circuit capable of measuring the magnitude of a signal. Thus, at the output of the combiner and after a high-power directional coupler (A-DC, A-Directional Coupler) it is possible to probe the
    degree of cancellation, for example using a spectrum analyzer or a power meter (A-PM, A-Power Meter). The output with low insertion losses ("through") of the directional coupler is connected to the vector network analyzer (VNA) through a protection network (A-VNN). This network basically includes a power limiter to protect the VNA from high power levels if the cancellation of the high power signal is not achieved.

    The device that polls the signals is connected to a control unit that processes and acts according to the measured signal level. The control unit includes a computer, a processor or any device that includes a processor. Thus, the cancellation level measured with the power meter by means of the directional coupler allows modifying the voltages I and Q of the vector modulator, in the preferred embodiment, to obtain the phase and the level of the A-CAN signal required for cancellation. .
     fifteen
    The required I-Q values are obtained in real time with a cancellation algorithm executed by the control unit (CU), which is connected to the A-PM. The control unit includes a digital-analog converter (DAC) for (or any circuit capable of) obtaining the voltages (or voltages) I and Q required for vector modulators or for obtaining the signals required by the device that is capable of modifying the amplitude and phase of the cancellation signals.

    The control unit executes any algorithm to determine the voltages I and Q required by the vector modulators to cancel the cancellation signals, or the signals required by the device that is capable of modifying the amplitude and phase required to cancel the signs. In this way the power level measured with the A-PM is minimized.

    When cancellation is achieved, the device that measures electrical quantities is a vector network analyzer (VNA), a scalar network analyzer, or any instrument capable of measuring the power of the signals. In this way, the dispersion parameter S11 or reflection coefficient of the DUT will be measured without distortion of the
    HP signal, which has been successfully canceled.

    The measuring instrument connectors must be protected with power limiters, diodes, or with any device that limits the power flowing to the instrument in order to ensure the quality of the measurement and its integrity.

    TRANSMITTED POWER

    The power transmitted through the DUT and the B-CAN signal are combined in a power combiner (B-PC). The attenuation and phase of the B-CAN signal will be modified so that both signals are canceled at the combiner output. The combiner must be able to dissipate the power of both signals when they are canceled. At the output of the combiner, a high-power directional coupler (B-DC) is placed to probe the signal level. For this, the power (B-15 PM) is measured at the docked port using, for example, a spectrum analyzer or a power meter. The trhough port of the directional coupler connects to the VNA through the network (B-VNN). This network includes a power limiter to protect the VNA from high power levels if HP signal cancellation is not achieved. twenty

    Probing the level of the canceled signal entering the VNA through the directional coupler allows modifying the voltage I and the voltage Q of the VM, in the preferred embodiment, to obtain the phase and attenuation of the B-CAN signal required for cancellation. 25

    The required I and Q values are obtained in real time with a cancellation algorithm executed by a control unit (CU), which is connected to the B-PM. The CU includes a processor and a DAC converter capable of generating the required I and Q voltages. The cancellation algorithm finds the best I and Q values to minimize the power level measured with the PM-B.

    When cancellation is obtained, the VNA will measure the dispersion parameters S21 or
    DUT transmission coefficient without distortion of the HP signal, which has been correctly canceled.

    VNA CALIBRATION
     5
    Before connecting the DUT, the VNA is calibrated in the reference plane (s) that correspond to the DUT connector (s) using a conventional calibration standard and with the HP signal generator turned off. The high power amplifiers used in the system can remain on.
     10
    Due to the insulators placed in CAN-A BRANCH, CAN-B BRANCH and DUT BRANCH, the calculated calibration error terms remain unchanged even when the HP signal generator is turned on by feeding the high-power amplifiers and thus changing its impedance of exit.
      fifteen
    BRIEF DESCRIPTION OF THE DRAWINGS

    Figure 1 shows the proposed architecture for measuring the dispersion parameters of a two-port device when the device is powered by a high power signal. 5

    Figure 2 shows the source, the SSN network and the power splitter

    Figure 3 shows the DUT branch (isolators, amplifiers and attenuators)
     10
    Figure 4 shows a cancellation branch (isolators, amplifiers, attenuators and vector modulator)

    Figure 5 shows the preferred embodiment of the proposed system
     fifteen


    PREFERRED EMBODIMENT OF THE INVENTION

    The preferred embodiment of the invention (Fig. 5) shows a feed-forward cancellation system that allows the measurement of the S parameters of two-port networks. The invention consists of several devices and circuits described below.

    The system has a signal source (SS) capable of generating a continuous wave signal at the frequency at which it is desired to characterize the device to be measured (DUT). After the source there is a network (SSN) that allows to adjust the power of the incoming signal 10 to the following stages of the measurement system and simultaneously, thanks to an isolator, to protect the source from any return of unwanted power.

    Then a power splitter (PS) with 3 output ports distributes the power from the SSN to the three branches of the measuring system. The central branch or 15 DUT BRANCH conducts a portion of the signal from the SSN to the DUT through a high power amplifier whose level can be adjusted by means of the attenuators at its input. At the output of the amplifier, an insulator protects it from the power that could come from the other branches or return from its own. The output of the isolator is connected to the input "input" of a directional device (DD) 20 that carries the high power (HP) signal to the DUT through the "through" output of the DD.

    The other two output ports of the PS power splitter are connected to two branches, called A-CAN BRANCH and B-CAN BRANCH that simultaneously modify 25 and independently both the magnitude and the phase of the signals from the SSN to cancel the signals of HP that are reflected and transmitted, respectively, by the DUT. The modification of the magnitude and of the phase is carried out with the intervention of a device that by means of control voltages allows said adjustment. The preferred device for executing said functionality would be a vector modulator (VM) whose transmission parameter S21 is controlled by phase (I) and quadrature (Q) voltages. To protect this device, an attenuator can be placed at its entrance, on each branch. Upon departure, also in
    Each branch has an amplifier that will raise the signal level to cancel the HP signal that comes from the corresponding DUT BRANCH. At the output of these power amplifiers an insulator is placed as a protection measure.
     5
    The HP signal of the A-CAN BRANCH is combined by a power combiner (A-PC) with the HP signal reflected by the DUT and from the "isolated" port of the DD. The combiner's output is taken to the "input" port of a directional coupler (A-DC) who directs the signal through its "through" port to one of the ports of a vector network analyzer (VNA). The “coupled” port of the 10 A-DC takes a sample of the signal to a power meter (A-PM), or to a spectrum analyzer, to evaluate the level of cancellation existing in that branch. Likewise, the HP signal of the B-CAN BRANCH is combined (B-PC) with the signal that crosses the DUT. A coupler (B-DC) takes said canceled signal to another of the VNA ports and simultaneously takes a sample of said signal to be able to measure its power (B-PM).

    The power levels measured by A-PM and B-PM are read by a control unit (CU) that has analog to digital converters (DAC). This information is used by a cancellation algorithm to conveniently modify the values of the control voltages (I and Q) of the VMs of the A-CAN BRANCH and B-CAN BRANCH branches and ensure the cancellation with the required level.

    It is important to note that the A-PC and B-PC combiners must be able to withstand the working powers when the cancellation becomes effective.
    权利要求:
    Claims (1)
    [1]

    1- A method to measure the electrical parameters of a single port or multiport device in working conditions with high power signals characterized in that 5
    to. It is based on a “feed-forward” technique of high power signals so that the high power signal is divided into two or more branches. One of them feeds the device through a port and the other or others are cancellation branches.
    b. The phase and amplitude of the signals of the cancellation branches are modified by circuits governed by a control unit. Said cancellation signals are combined with the output signals (dispersed in reflection and transmission) of the device so that they are canceled.
    C. At the same time the device is fed by low power signals to characterize its electrical parameters by means of a network analyzer or instrument suitable for this purpose.
    d. The calibration necessary to measure the electrical parameters is performed following the standard low power calibration procedure. twenty
    2- A method for measuring electrical parameters of a single port or multiport device under high power signals according to claim 1 characterized in that the measuring instrument measures impedance, admittance or transmission parameters. 25
    3- A measuring system to measure the dispersion parameters of a single port or multiport device under high power signals characterized by
    to. The power of a signal source is divided into at least two or more 30 branches. The signal of a path (DUT branch) is conditioned by a set of components (attenuators, amplifiers and insulators) and is connected to a port (connector)
    of the device under test. The remaining branches, the cancellation branches, are comprised of a set of components that adapt the power level and phase of the cancellation signals to the magnitude and phase of the signals dispersed in the DUT.
    b. The power reflected in the DUT input port and the power 5 transmitted in the remaining DUT ports are combined with the cancellation signals through the use of combiners or splitters.
    C. The phase and attenuation of the cancellation signals are changed dynamically and in real time by circuits controlled by a control unit (processor) to cancel the reflected and transmitted power that are dispersed in the DUT.
    d. The outputs of the power combiners are connected to a network analyzer including protective limiting circuits to prevent deterioration of the measuring equipment during the cancellation process. fifteen
    4- A measuring system according to claim 3 characterized in that the signal source is conditioned with one or more attenuators and one or more insulators
    5- A measuring system according to claim 3 characterized in that the branch 20 DUT can include one or more attenuators, one or more amplifiers and one or more insulators or circulators.
    6- A measuring system according to claim 3 characterized in that one or more cancellation branches may include one or more attenuators, one or more amplifiers, one or more insulators or circulators and one or more vector modulators, which are capable of changing the phase and magnitude of the signal.
    7- A measuring system according to claim 3 characterized in that one or more cancellation branches may include one or more attenuators, one or more amplifiers, one or more insulators or circulators and one or more attenuators and variable phase shifters, which are capable of change the phase and signal amplitude
    8- A measurement system according to claim 3 characterized in that one or more cancellation branches may include one or more attenuators, one or more amplifiers, one or more insulators or circulators and one or more components with the mission of changing the amplitude and / or the phase of the cancellation signals. 5
    A measurement system according to claim 3 characterized in that the DUT branch includes components that are capable of changing the phase and amplitude of the DUT branch signal instead of changing the amplitude and phase of the cancellation signals. 10
    10. A measuring system according to claim 3 characterized in that the power reflected in the input DUT is obtained by using a 3 dB coupler.
     fifteen
    11- A measurement system according to claim 3 characterized in that the power reflected in the input DUT is obtained by using a directional bridge.
    12- A measurement system according to claim 3 characterized in that the power 20 reflected in the input DUT is obtained by using any reciprocal device that is capable of separating the incident power from that reflected in a device.
    13. A measurement system according to claim 3 characterized in that the 25 signals dispersed in the DUT and the cancellation signals are combined using Wilkinson combiners.
    A measurement system according to claim 3 characterized in that the signals dispersed in the DUT and the cancellation signals are combined using power combiners.
    15- A measurement system according to claim 3 characterized in that the signals dispersed in the DUT and the cancellation signals are combined using 3 dB couplers.
    16- A measurement system according to claim 3 characterized in that the 5 signals dispersed in the DUT and the cancellation signals are combined using any device that combines, totally or partially, the input signal of two ports and the resulting signal flows to a third port.
    17- A measurement system according to claim 3 characterized in that once the DUT signal and the cancellation signal are combined, the resulting signal is probed using a directional coupler and a power meter.
    18- A measurement system according to claim 3 characterized in that once the DUT signal and the cancellation signal are combined, the resulting signal 15 is probed using a directional coupler and a spectrum analyzer
    A measurement system according to claim 3 characterized in that once the DUT signal and the cancellation signal are combined, the resulting signal is probed using any device or circuit capable of measuring the magnitude of a signal.
    A measurement system according to claim 3 characterized in that the device that probes the signals according to claims 17-19 is connected to a control unit that processes and acts according to the level of the measured signal.
    21- A measuring system according to claim 3 characterized in that the control unit includes a computer.
     30
    22- A measuring system according to claim 3 characterized in that the control unit includes a processor or any device that includes a processor.
    23- A measurement system according to claim 3 characterized in that the control unit includes a digital-analog converter to obtain the voltages I and Q required for the vector modulators.
     5
    24- A measuring system according to claim 3 characterized in that the control unit includes a digital-analog converter to obtain the signals required by the device that is capable of modifying the amplitude and phase of the cancellation signals
     10
    25- A measurement system according to claim 3 characterized in that the control unit includes any circuit capable of synthesizing the voltages I and Q required for vector modulators.
    26- A measurement system according to claim 3 characterized in that the control unit 15 includes any circuit capable of synthesizing the signals required by the device that is capable of modifying the amplitude and phase of the cancellation signals
    27- A measurement system according to claim 3 characterized in that the control unit 20 executes any algorithm to determine the required voltages I and Q of the vector modulators that are required to cancel the signals.
    28- A measurement system according to claim 3 characterized in that the control unit 25 executes any algorithm to determine the signals required by the device that is capable of modifying the amplitude and phase required to cancel the signals.
    29. A measuring system according to claim 3 characterized in that the device that measures the electrical quantities is a vector network analyzer.
    30- A measuring system according to claim 3 characterized in that the device that measures the electrical quantities is a scalar network analyzer.
    31- A measuring system according to claim 3 characterized in that the device that measures the electrical quantities is any instrument capable of measuring the power of the signals.
    32- A measuring system according to claim 3 characterized in that the connectors of the measuring instrument are protected with power limiters. 10
    33- A measuring system according to claim 3 characterized in that the connectors of the measuring instrument are protected with diodes.
    34- A measuring system according to claim 3 characterized in that the 15 connectors of the measuring instrument are protected with any device that limits the power flowing to the instrument.

     twenty
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