A through-type radio frequency microwave vector analysis device and method

Abstract

The application discloses a kind of through type radio frequency microwave vector analysis device and method, device includes radio frequency front end and down conversion module, digital acquisition and processing module and control and interactive module.Radio frequency front end and down conversion module are used for the transmission of radio frequency signal, two-way coupling sampling and coherent down conversion;Digital acquisition and processing module are used for collecting signal and processing, obtain pure incident wave signal and reflected wave signal;Control and interactive module are used for controlling each module, and carry out man-machine interaction.The application is realized by using through type measurement architecture, under the premise that the signal transmission of measured system is not interrupted, realizes the online vector analysis of radio frequency signal, and does not need built-in signal source, and then complete vector parameter such as reflection coefficient, impedance, standing wave ratio can be accurately calculated.

Description

Technical Field

[0001] This invention relates to the field of radio frequency measurement technology, and in particular to a through-type radio frequency microwave vector analysis device and method. Background Technology

[0002] Radio frequency microwave vector analysis is a key technology for testing radio frequency microwave systems. By measuring signal amplitude and phase, core parameters such as reflection coefficient, impedance, and standing wave ratio can be derived, providing support for equipment research and development, debugging, and fault diagnosis.

[0003] In current mainstream measurement technologies, the vector network analyzer (VNA) is the core device for achieving high-precision vector analysis. However, traditional vector network analyzers (VNAs) adopt a reflective architecture, which requires interrupting the link of the system under test and connecting to the test port. They also rely on a built-in high-quality signal source, resulting in limitations such as high cost, large size, and inability to reflect the actual operating status of the device in real time.

[0004] To address the link interruption problem in offline measurements, passive monitoring devices such as through-type power meters have emerged in the existing technology. However, these devices can only acquire power amplitude information, lack phase data, and cannot calculate vector parameters, making it difficult to meet the needs of accurate debugging and fault diagnosis. Summary of the Invention

[0005] The purpose of this invention is to provide a through-type radio frequency microwave vector analysis device and method, which solves the problem in the prior art that it is impossible to perform accurate online vector parameter measurement under normal operating conditions of the radio frequency system.

[0006] To address the aforementioned technical problems, in one aspect, the present invention provides a through-type radio frequency microwave vector analysis device, comprising: The radio frequency (RF) front-end and down-conversion module are used for RF signal transmission, bidirectional coupling sampling, and coherent down-conversion. It includes an RF front-end unit and a coherent dual-channel down-conversion unit. The RF front-end unit includes a dual directional coupler, which has a forward coupling port and a reverse coupling port, used to couple incident and reflected waves while transmitting RF signals. The coherent dual-channel down-conversion unit includes a first down-conversion channel and a second down-conversion channel, respectively connected to the forward coupling port and the reverse coupling port, and uses the local oscillator signal from the same local oscillator source for down-conversion. The digital acquisition and processing module includes a synchronous acquisition unit and a digital signal processing unit. The synchronous acquisition unit synchronously samples the signals from the first down-conversion channel and the second down-conversion channel. The digital signal processing unit converts the acquired signals into complex signals and performs vector separation operations to obtain pure incident wave signals and reflected wave signals. The control and interaction module is used to control the various modules and perform human-computer interaction.

[0007] Furthermore, the RF front-end unit also includes an RF input port, a power divider, a local oscillator (LO) frequency synthesizer, and a load under test (UTP) port; the dual directional coupler is disposed between the RF input port and the UTP port. The power divider is connected to the local oscillator (LO) frequency synthesizer and is used to divide the local oscillator signal into a phase-coherent first local oscillator signal and a second local oscillator signal, which are respectively provided to the first down-conversion channel and the second down-conversion channel.

[0008] Furthermore, the first downconversion channel includes a first mixer, a first intermediate frequency filter, and a first intermediate frequency gain controllable amplifier connected in sequence. The RF input terminal of the first mixer is connected to the positive coupling port, and the local oscillator input terminal is connected to the first output terminal of the power divider. The second downconversion channel includes a second mixer, a second intermediate frequency filter, and a second intermediate frequency gain controllable amplifier connected in sequence. The RF input terminal of the second mixer is connected to the reverse coupling port, and the local oscillator input terminal is connected to the second output terminal of the power divider.

[0009] Furthermore, the first downconversion channel and the second downconversion channel adopt a zero intermediate frequency architecture or a fixed low intermediate frequency architecture.

[0010] Furthermore, the synchronous acquisition unit includes a first high-speed analog-to-digital converter and a second high-speed analog-to-digital converter; The first high-speed analog-to-digital converter is connected to the output terminal of the first down-conversion channel to perform analog-to-digital conversion on the signal output by the first down-conversion channel to obtain a first digital signal. The second high-speed analog-to-digital converter is connected to the output terminal of the second down-conversion channel to perform analog-to-digital conversion on the signal output by the second down-conversion channel to obtain the second digital signal; The first high-speed analog-to-digital converter and the second analog-to-digital converter synchronously transmit the first digital signal and the second digital signal to the digital signal processing unit, respectively.

[0011] Furthermore, the digital signal processing unit includes a field-programmable gate array (FPGA), which comprises the following functional parts: The digital downconversion and filtering section is used to perform digital downconversion and digital filtering on the first digital signal and the second digital signal. The FFT calculation part is used to perform a fast Fourier transform on the processed signal, converting the time-domain signal into a first complex signal sequence and a second complex signal sequence in the frequency domain. The vector separation operation section performs vector separation operations on the first complex signal sequence and the second complex signal sequence based on the calibration matrix to calculate the pure incident wave signal and reflected wave signal; The parameter calculation section is used to calculate the spectrum, power, reflection coefficient, impedance, and standing wave ratio parameters based on the incident wave signal and the reflected wave signal. The calibration parameter storage section is used to store the calibration matrix.

[0012] Furthermore, the control and interaction module includes: The microcontroller is used to coordinate the synchronous operation of the RF front-end, downconversion module, and digital acquisition and processing module, execute calibration process control, control RF switch switching, receive and process signals from the digital signal processing unit, and respond to user operation commands and control the working status of each module. The human-computer interaction unit is used to display measurement results and receive user operations.

[0013] On the other hand, the present invention also provides a through-type radio frequency microwave vector analysis method, based on the above-mentioned through-type radio frequency microwave vector analysis device, comprising the following steps: Radio frequency signals are transmitted in the radio frequency front-end unit, and at the same time, the forward coupling port and the reverse coupling port of the dual directional coupler couple out the first coupling signal and the second coupling signal, respectively. The first coupling signal and the second coupling signal are respectively input into the first down-conversion channel and the second down-conversion channel, and the first local oscillator signal and the second local oscillator signal are used to perform coherent down-conversion to obtain the first intermediate frequency signal and the second intermediate frequency signal. The first intermediate frequency signal and the second intermediate frequency signal are synchronously sampled by the synchronous acquisition unit to obtain the first digital signal and the second digital signal; The first digital signal and the second digital signal are processed to obtain a first complex signal sequence and a second complex signal sequence; Based on the calibration matrix, vector separation operations are performed on the first complex signal sequence and the second complex signal sequence to obtain pure incident wave signal and reflected wave signal, thereby obtaining the vector information of the radio frequency signal under actual working conditions.

[0014] Furthermore, the calibration matrix is ​​obtained through the following steps: The load under test is connected to a matching load, and a frequency sweep measurement is performed across the entire measurement frequency band. The first set of complex signals is acquired and recorded at each frequency point. The load under test is connected to a short-circuited standard component, and a frequency sweep measurement is performed across the entire measurement frequency band. The second set of complex signals is collected and recorded at each frequency point. The load under test is connected to an open-circuit standard component, and a frequency sweep measurement is performed across the entire measurement frequency band. The third set of complex signals is collected and recorded at each frequency point. Based on three sets of complex signals and the known reflection coefficient of the standard component, solve for the four complex coefficients of the complex coefficient matrix at each frequency point; Calculate the inverse of the complex coefficient matrix, use the resulting inverse matrix as the calibration matrix, and store it.

[0015] Furthermore, the vector separation operation on the first complex signal sequence and the second complex signal sequence based on the calibration matrix specifically includes: Establish a model relating the measured signal and the pure signal: Assuming the pure incident wave is F(t) and the reflected wave is R(t), and the measured first complex signal sequence and second complex signal sequence output from the first down-conversion channel and the second down-conversion channel are a(t) and b(t) respectively, then the relationship between them can be expressed as: a(t)=M_11×F(t)+M_12×R(t) (1); b(t)=M_21×F(t)+M_22×R(t) (2); Where M is a 2×2 complex coefficient matrix, and M_11, M_12, ​​M_21 and M_22 are the four complex coefficients of the complex coefficient matrix M; According to formulas (1) and (2), we can obtain: [F(t)] [a(t)] [R(t)]=inv(M)×[b(t)]; Here, inv(M) is the inverse of the complex coefficient matrix.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects: This invention employs a through-type measurement architecture to achieve online vector analysis of radio frequency (RF) signals without interrupting the signal transmission of the system under test, and without requiring a built-in signal source. It utilizes dual directional couplers to simultaneously extract incident and reflected wave signals, combined with coherent dual-channel down-conversion technology to maintain phase coherence between the two channels. By establishing a complex coefficient matrix model, it effectively eliminates system errors introduced by non-ideal directivity of the directional couplers and amplitude-phase inconsistency between the two channels, thereby achieving accurate separation of incident and reflected waves. This allows for precise calculation of complete vector parameters such as reflection coefficient, impedance, and VSWR. The device proposed in this invention requires no built-in signal source and can rely on the actual operating signal of the system under test for measurement, truly reflecting the performance characteristics of the RF system under actual operating conditions. It is suitable for applications such as transmitter output monitoring and online antenna debugging. Compared with traditional instruments, this invention significantly reduces equipment cost and size, and enables real-time, continuous vector parameter monitoring under actual equipment operating conditions, providing an effective technical means for accurate debugging and fault diagnosis of RF microwave systems. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the through-type radio frequency microwave vector analysis device in Embodiment 1 of the present invention; Figure 2 This is a flowchart of the through-type radio frequency microwave vector analysis method in Embodiment 2 of the present invention.

[0018] Reference numerals: 1. RF front-end and downconversion module; 2. Digital acquisition and processing module; 3. Control and interaction module. Detailed Implementation

[0019] Based on the teachings of this specification, those skilled in the art can form new technical solutions by combining different implementation methods without creating technical contradictions. Such variations should be considered to fall within the protection scope of this application.

[0020] The present invention will now be described in more detail with reference to the schematic diagrams, which illustrate preferred embodiments of the invention. It should be understood that those skilled in the art can modify the invention described herein while still achieving its advantageous effects. Therefore, the following description should be understood as being of general knowledge to those skilled in the art and is not intended to limit the invention.

[0021] The invention is described more specifically by way of example in the following paragraphs with reference to the accompanying drawings. The advantages and features of the invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the invention.

[0022] Example 1 like Figure 1 As shown in the figure, this embodiment of the invention proposes a through-type radio frequency microwave vector analysis device, including a radio frequency front-end and down-conversion module 1, a digital acquisition and processing module 2, and a control and interaction module 3.

[0023] The radio frequency front-end and downconversion module 1 are used for radio frequency signal transmission, bidirectional coupling sampling and coherent downconversion, and include a radio frequency front-end unit and a coherent dual-channel downconversion unit.

[0024] The RF front-end unit includes a dual directional coupler, comprising a forward coupling port and a reverse coupling port, used to couple incident and reflected waves simultaneously during RF signal transmission. This dual directional coupler design allows for the simultaneous acquisition of sample signals of both incident and reflected waves without interrupting the main transmission path. The forward coupling port primarily couples the incident wave component transmitted from the RF input port to the load under test (DUT) port, while the reverse coupling port primarily couples the reflected wave component reflected back from the DUT port. Although a small amount of reflected wave leakage may occur at the forward coupling port and a small amount of incident wave leakage at the reverse coupling port due to the directional limitation of the coupler, these aliasing errors can be eliminated through subsequent calibration and vector separation operations.

[0025] The coherent dual-channel downconversion unit includes a first downconversion channel and a second downconversion channel, which are connected to the forward coupling port and the reverse coupling port, respectively, and use the local oscillator signal from the same local oscillator source for downconversion. The coherent dual-channel downconversion architecture ensures that both downconversion channels use the same local oscillator signal, maintaining a strict phase coherence relationship between the two signals. This results in deterministic and consistent phase changes introduced during the downconversion process of both channels. This coherent downconversion method preserves the relative phase relationship between the incident and reflected waves, laying the foundation for accurate extraction of vector information.

[0026] The digital acquisition and processing module 2 includes a synchronous acquisition unit and a digital signal processing unit. The synchronous acquisition unit synchronously samples signals from the first down-conversion channel and the second down-conversion channel. The digital signal processing unit converts the acquired signals into complex signals and performs vector separation operations to obtain pure incident and reflected wave signals. Synchronous acquisition ensures a strict temporal correspondence between the two signals, avoiding phase errors caused by inconsistent sampling times. The digital signal processing unit achieves fine signal processing through digitization, offering greater flexibility and accuracy.

[0027] The control and interaction module 3 is used to control the various modules and perform human-computer interaction. The control and interaction module 3 coordinates the workflow of the entire device, responds to user operation commands, and presents the measurement results to the user in an intuitive way.

[0028] In this embodiment, the RF front-end unit further includes an RF input port, a power divider, a local oscillator (LO) frequency synthesizer, and a load under test (UTD) port. The dual directional coupler is disposed between the RF input port and the UTD port. The RF signal is input from the RF input port, passes through the dual directional coupler, and is transmitted to the UTD port. During this transmission process, the dual directional coupler performs coupled sampling of the incident and reflected waves.

[0029] In one specific embodiment, the directional coupler is a device with a directivity greater than 30dB and a coupling degree of 30 / 40dB, such as the Mini-Circuits ZABDC20-362H+ model. This model of directional coupler can provide good directivity and appropriate coupling degree to meet the accurate sampling requirements of incident and reflected waves.

[0030] The power divider is connected to the local oscillator (LO) frequency synthesizer and is used to distribute the local oscillator signal into a first LO signal and a second LO signal with phase coherence, which are then provided to the first down-conversion channel and the second down-conversion channel, respectively. The LO frequency synthesizer generates a highly stable local oscillator signal, which is then split in two by the power divider to form two LO signals with slightly different amplitudes but strictly coherent phases. The power divider, while maintaining phase coherence, appropriately distributes the LO signals to the two down-conversion channels.

[0031] In one specific embodiment, the local oscillator source employs a low phase noise frequency synthesis chip, such as the ADF4351. This chip has excellent phase noise performance and can provide a high-quality local oscillator signal.

[0032] In this embodiment, the first down-conversion channel includes a first mixer, a first intermediate frequency (IF) filter, and a first IF gain controllable amplifier connected in sequence. The RF input terminal of the first mixer is connected to the forward coupling port, and the local oscillator (LO) input terminal is connected to the first output terminal of the power divider. The first mixer mixes the RF signal from the forward coupling port with the first LO signal, converting the high-frequency RF signal into a lower-frequency IF signal. The first IF filter filters the mixed signal, suppressing unwanted components such as image frequency and LO leakage, and extracting the required IF signal. The first IF gain controllable amplifier amplifies the filtered IF signal, and its gain can be adjusted according to the input signal strength, so that the output signal amplitude matches the input range of the subsequent analog-to-digital converter, achieving dynamic range optimization.

[0033] The second down-conversion channel includes a second mixer, a second intermediate frequency filter, and a second intermediate frequency gain-controlled amplifier connected in sequence. The RF input terminal of the second mixer is connected to the reverse coupling port, and the local oscillator input terminal is connected to the second output terminal of the power divider. The operating principle of the second down-conversion channel is similar to that of the first down-conversion channel, performing down-conversion, filtering, and gain control processing on the RF signal from the reverse coupling port. The two down-conversion channels are symmetrical in circuit structure and have strictly equal wiring lengths, and use performance-matched components to reduce the inherent differences between the two channels.

[0034] Furthermore, the first and second down-conversion channels employ either a zero-IF architecture or a fixed low-IF architecture. A zero-IF architecture means the local oscillator frequency is the same as the RF signal frequency, resulting in a baseband signal directly after down-conversion, with an intermediate frequency (IF) of zero. The advantage of a zero-IF architecture is that it eliminates the need for an IF filter, simplifying the circuit structure, but it requires addressing issues such as DC bias and local oscillator leakage. A fixed low-IF architecture means the local oscillator frequency differs from the RF signal frequency by a fixed IF frequency, resulting in a fixed-frequency IF signal after down-conversion. The fixed low-IF architecture facilitates the use of IF filters with fixed parameters, providing better filtering performance, and avoids the DC bias problem inherent in the zero-IF architecture. The choice between a zero-IF or fixed low-IF architecture can be flexibly made based on actual application requirements and the complexity of the circuit implementation.

[0035] In practical implementation, both the first and second mixers can be double-balanced mixers, such as the ADE-1MH model. This model of mixer has high linearity and good port isolation, and can effectively suppress local oscillator leakage and image interference.

[0036] In this embodiment, the synchronous acquisition unit includes a first high-speed analog-to-digital converter and a second high-speed analog-to-digital converter.

[0037] The first high-speed analog-to-digital converter (ADC) is connected to the output of the first down-conversion channel and performs analog-to-digital conversion on the signal output from the first down-conversion channel to obtain a first digital signal. The second high-speed ADC is connected to the output of the second down-conversion channel and performs analog-to-digital conversion on the signal output from the second down-conversion channel to obtain a second digital signal. The first and second ADCs synchronously transmit the first and second digital signals to the digital signal processing unit, respectively. The two high-speed ADCs use the same sampling clock for synchronous sampling. The frequency of the sampling clock needs to meet the requirements of the Nyquist sampling theorem and is typically more than twice the signal bandwidth. The number of bits in the high-speed ADC determines the amplitude quantization accuracy. A higher number of bits results in lower quantization noise and a larger dynamic range, but also increases circuit complexity and power consumption. In practical applications, a comprehensive consideration of performance and cost is required when making the selection.

[0038] In the specific implementation process, the first high-speed analog-to-digital converter and the second high-speed analog-to-digital converter (ADC) can be dual-channel, 14-bit resolution, and sampling rate of 100MSPS or higher, such as AD9680, so as to provide sufficient sampling bandwidth and quantization accuracy, and a sufficiently large dynamic range to meet the requirements of high-speed real-time acquisition.

[0039] In this embodiment, the digital signal processing unit includes a field-programmable gate array (FPGA), which includes the following functional parts: The digital downconversion and filtering section is used to perform digital downconversion and digital filtering on the first digital signal and the second digital signal.

[0040] The FFT calculation section performs a Fast Fourier Transform on the processed signal, converting the time-domain signal into a first and a second complex signal sequence in the frequency domain. Through the FFT transform, the time-domain sampled signal can be converted into a complex sequence in the frequency domain, with each frequency point corresponding to a complex value. Frequency domain processing facilitates the separate analysis and processing of different frequency components and also facilitates subsequent vector separation operations.

[0041] The vector separation operation section performs vector separation operations on the first and second complex signal sequences based on the calibration matrix to calculate the pure incident and reflected wave signals. The calibration matrix is ​​the inverse of a complex coefficient matrix predetermined during the calibration process and is stored in the calibration parameter storage section.

[0042] The parameter calculation section is used to calculate the spectrum, power, reflection coefficient, impedance, and standing wave ratio parameters based on the incident wave signal and the reflected wave signal.

[0043] The calibration parameter storage section is used to store the calibration matrix.

[0044] In the specific implementation process, the field-programmable gate array can use Xilinx's Artix-7 series or Zynq-7000 series chips. These chips have abundant logic resources and DSP hard cores, which can efficiently implement complex digital signal processing algorithms such as digital downconversion, FFT operation, and vector separation, and meet the performance requirements of real-time processing.

[0045] In this embodiment, the control and interaction module 3 includes a microcontroller and a human-computer interaction unit.

[0046] The microcontroller is used to coordinate the synchronous operation of the RF front-end, downconversion module 1, and digital acquisition and processing module 2, receive and process signals from the digital signal processing unit, and respond to user operation commands and control the working status of each module.

[0047] The human-machine interface unit is used to display measurement results and receive user operations. It uses interactive methods such as LCD screen, touch screen, buttons, and knobs to present measurement results such as spectrum, power, reflection coefficient, impedance, and standing wave ratio to the user in a graphical or numerical form, while receiving user settings and control commands.

[0048] Example 2 like Figure 2As shown, this embodiment provides a through-feed radio frequency microwave vector analysis method. The through-feed radio frequency microwave vector analysis method is based on the through-feed radio frequency microwave vector analysis device described in Embodiment 1, and includes the following steps: Radio frequency signals are transmitted in the radio frequency front-end unit, and at the same time, the forward coupling port and the reverse coupling port of the dual directional coupler couple out the first coupling signal and the second coupling signal, respectively.

[0049] Specifically, the first coupling signal mainly contains the incident wave component, and the second coupling signal mainly contains the reflected wave component. The radio frequency (RF) signal is input from the RF input port, transmitted through the main transmission path of the dual directional coupler to the load under test (DUT) port, and connected to the DUT. During signal transmission, the forward coupling port of the dual directional coupler couples out a portion of the energy as the first coupling signal, which mainly reflects the incident wave transmitted from the RF input port to the DUT. If the DUT is not perfectly matched to the device's characteristic impedance, a reflected wave will be generated. This reflected wave travels from the DUT port to the RF input port, and the reverse coupling port of the dual directional coupler couples out a portion of the reflected wave energy as the second coupling signal. Because the directionality of the directional coupler is not infinite, a small amount of leakage from the reflected wave will be mixed into the first coupling signal, and a small amount of leakage from the incident wave will be mixed into the second coupling signal.

[0050] The first coupling signal and the second coupling signal are respectively input into the first down-conversion channel and the second down-conversion channel, and coherent down-conversion is performed using the first local oscillator signal and the second local oscillator signal to obtain the first intermediate frequency signal and the second intermediate frequency signal. Since the first local oscillator signal and the second local oscillator signal come from the same local oscillator source and are distributed by the power divider, they maintain phase coherence. Therefore, the phase changes introduced by the two down-conversion processes have a definite relationship. The phase relationship between the first intermediate frequency signal and the second intermediate frequency signal can accurately reflect the phase relationship between the first coupling signal and the second coupling signal, and thus reflect the phase relationship between the incident wave and the reflected wave.

[0051] The first intermediate frequency (IF) signal and the second IF signal are synchronously sampled by a synchronous acquisition unit to obtain a first digital signal and a second digital signal. The first high-speed analog-to-digital converter (ADC) and the second high-speed ADC use the same sampling clock to sample and quantize the first and second IF signals simultaneously. The sampling frequency is determined based on the bandwidth of the IF signal. Synchronous sampling ensures that the two digital signals are strictly corresponding in time, providing a prerequisite for subsequent synchronous processing and phase comparison.

[0052] The first digital signal and the second digital signal are processed to obtain a first complex signal sequence and a second complex signal sequence.

[0053] In this embodiment, the first and second digital signals undergo digital down-conversion, digital filtering, and fast Fourier transform, thereby converting the first and second digital signals acquired by the first and second high-speed analog-to-digital converters into a first complex signal sequence and a second complex signal sequence. These complex signal sequences contain amplitude and phase information of the incident and reflected waves, providing accurate frequency domain data for subsequent vector separation operations based on the calibration matrix, thus enabling the separation of pure incident and reflected wave signals.

[0054] Based on the calibration matrix, vector separation operations are performed on the first complex signal sequence and the second complex signal sequence to obtain pure incident wave signal and reflected wave signal, thereby obtaining the vector information of the radio frequency signal under actual working conditions.

[0055] In this embodiment, the vector separation operation on the first complex signal sequence and the second complex signal sequence based on the calibration matrix specifically includes: Establish a model relating the measured signal and the pure signal: Assuming the pure incident wave is F(t) and the reflected wave is R(t), and the measured first complex signal sequence and second complex signal sequence output from the first down-conversion channel and the second down-conversion channel are a(t) and b(t) respectively, then the relationship between them can be expressed as: a(t)=M_11×F(t)+M_12×R(t) (1); b(t)=M_21×F(t)+M_22×R(t) (2); Where M is a 2×2 complex coefficient matrix, and M_11, M_12, ​​M_21, and M_22 are the four complex coefficients of the complex coefficient matrix M. This model describes the measured signal as a linear combination of a pure incident wave and a reflected wave, with complex coefficients that include the effects of amplitude and phase. Complex coefficients M11 and M21 reflect the response of the incident wave in the two channels after passing through the dual directional coupler and dual-channel downconversion, while complex coefficients M12 and M22 reflect the response of the reflected wave. If the directional coupler is perfectly directive and the two channels are completely aligned, then complex coefficients M12 and M21 should be zero, but in reality they are not zero, representing signal aliasing.

[0056] According to formulas (1) and (2), we can obtain: [F(t)] [a(t)] [R(t)]=inv(M)×[b(t)]; Here, inv(M) is the inverse of the complex coefficient matrix. By performing inverse matrix operations, the pure incident and reflected waves can be deduced from the measured aliased signals a(t) and b(t).

[0057] In this embodiment, the calibration matrix is ​​obtained through the following steps: The load under test is connected to a matching load, and a frequency sweep measurement is performed across the entire measurement frequency band. The first set of complex signals is collected and recorded at each frequency point.

[0058] Specifically, the matching load is a standard load with a known and near-zero reflection coefficient, typically a 50Ω precision matching load. After connecting the matching load to the port of the load under test, the device generates virtually no reflected waves. The local oscillator (LO) frequency synthesizer scans progressively from the starting frequency of the measurement band to the ending frequency, measuring each frequency point. At each frequency point, after down-conversion, sampling, digital processing, and FFT transformation, a first complex signal and a second complex signal are obtained. These two complex signals are recorded as the first set of complex signals. Since the reflection coefficient of the matching load is approximately 0, the first coupled signal mainly contains the incident wave, and the second coupled signal is theoretically very small.

[0059] That is, for a matched load, Γ_match≈0, R_match≈0, meaning the following is measured: a_match≈M11×F_match ①; b_match≈M21×F_match ②; From formulas ① and ②, we can obtain: M_21 / M_1=b_match(f) / a_match(f) ③.

[0060] Wherein, Γ_match represents the reflection coefficient of the matched load, R_match represents the pure reflected wave signal when the matched load is connected, F_match represents the pure incident wave signal when the matched load is connected; a_match represents the first complex signal sequence output by the first down-converter channel when the matched load is connected; and b_match represents the second complex signal sequence output by the second down-converter channel when the matched load is connected.

[0061] The load under test is connected to a short-circuit standard component, and a frequency sweep measurement is performed across the entire measurement frequency band. The second set of complex signals is collected and recorded at each frequency point.

[0062] Specifically, the short-circuit standard is a standard load with a known reflection coefficient of -1 (the ideal short-circuit reflection coefficient is -1, and the phase is 180 degrees). After connecting the short-circuit standard to the port of the load under test, the incident wave is completely reflected, and the reflected wave has the same amplitude and opposite phase to the incident wave. The entire measurement frequency band is swept, and the third and fourth complex signals are recorded at each frequency point as the second set of complex signals. Due to total reflection, the second coupled signal will be significantly enhanced, and the first coupled signal will also change due to the leakage of the reflected wave.

[0063] For a short-circuit standard component, Γ_short = -1, which means R_short = -F_short, and the measured values ​​are: a_short=M11×F_short-M12×F_short ④; b_short=M21×F_short-M22×-F_short ⑤.

[0064] Wherein, Γ_short represents the reflection coefficient when the standard component is short-circuited, R_short represents the pure reflected wave signal when the standard component is short-circuited, F_short represents the pure incident wave signal when the standard component is short-circuited, a_short represents the third complex signal sequence output by the first down-converter channel when the standard component is short-circuited, and b_short represents the fourth complex signal sequence output by the second down-converter channel when the standard component is short-circuited.

[0065] The load under test is connected to an open-circuit standard component, and a frequency sweep measurement is performed across the entire measurement band. The third set of complex signals is collected and recorded at each frequency point.

[0066] Specifically, the open-circuit standard is a standard load with a known reflection coefficient of +1 (the ideal open-circuit reflection coefficient is +1, and the phase is 0 degrees). After connecting the open-circuit standard to the port of the load under test, the incident wave is also completely reflected, but the reflected wave is in phase with the incident wave. The entire measurement frequency band is swept, and the fifth and sixth complex signals are recorded at each frequency point as the third set of complex signals. The open-circuit standard and the short-circuit standard have the same reflection coefficient amplitude but different phases, providing different phase conditions, which helps to accurately solve the various complex coefficients of the calibration matrix.

[0067] For an open-circuit standard component, Γ_open = +1, meaning R_open = F_open, which means the measured value is: a_open=M11×F_open+M12×F_open ⑥ b_open=M21×F_open+M22×F_open ⑦ Wherein, Γ_open represents the reflection coefficient when the open-circuit standard component is connected, R_open represents the pure reflected wave signal when the open-circuit standard component is connected, F_open represents the pure incident wave signal when the open-circuit standard component is connected; a_open represents the fifth complex signal sequence output by the first down-converter channel when the open-circuit standard component is connected; and b_open represents the sixth complex signal sequence output by the second down-converter channel when the open-circuit standard component is connected.

[0068] Based on three sets of complex signals and the known reflection coefficient of the standard component, solve for the four complex coefficients of the complex coefficient matrix at each frequency point.

[0069] Assuming the incident power at the RF input port remains stable across the three measurements (i.e., F_match, F_short, and F_open are essentially equal or can be normalized), a system of equations concerning the complex coefficients M11, M12, M21, and M22 can be established using formulas ③, ④, ⑤, ⑥, and ⑦. Solving this system of equations yields the four complex coefficients. In practice, matrix operations or numerical optimization methods can be used to solve the problem.

[0070] Calculate the inverse of the complex coefficient matrix, use the resulting inverse matrix as the calibration matrix, and store it.

[0071] By sweeping measurements across the entire frequency band, the complex coefficient matrix at each frequency point can be uniquely and accurately calculated. The inverse of this complex coefficient matrix is ​​then calculated and stored as a calibration file for subsequent measurements of the device under test. This process is repeated for all frequency points to establish a complete calibration matrix database. In subsequent actual measurements, the calibration matrix for the corresponding frequency point is directly called for vector separation operations, eliminating the need to repeat the calibration process. Recalibration is only required when the device hardware changes or when higher accuracy is needed.

[0072] In summary, the device proposed in this invention does not require a built-in signal source and can rely on the actual operating signal of the system under test for measurement, truly reflecting the performance characteristics of the radio frequency system under actual operating conditions. It is suitable for applications such as transmitter output monitoring and online antenna debugging. Compared with traditional instruments, this invention significantly reduces equipment cost and size, and can perform real-time, continuous vector parameter monitoring under actual equipment operating conditions, providing an effective technical means for precise debugging and fault diagnosis of radio frequency microwave systems.

[0073] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A through-type radio frequency microwave vector analysis device, characterized in that, include: The radio frequency (RF) front-end and down-conversion module are used for RF signal transmission, bidirectional coupling sampling, and coherent down-conversion. It includes an RF front-end unit and a coherent dual-channel down-conversion unit. The RF front-end unit includes a dual directional coupler, which has a forward coupling port and a reverse coupling port, used to couple incident and reflected waves while transmitting RF signals. The coherent dual-channel down-conversion unit includes a first down-conversion channel and a second down-conversion channel, respectively connected to the forward coupling port and the reverse coupling port, and uses the local oscillator signal from the same local oscillator source for down-conversion. The digital acquisition and processing module includes a synchronous acquisition unit and a digital signal processing unit. The synchronous acquisition unit synchronously samples the signals from the first down-conversion channel and the second down-conversion channel. The digital signal processing unit converts the acquired signals into complex signals and performs vector separation operations to obtain pure incident wave signals and reflected wave signals. The control and interaction module is used to control the various modules and perform human-computer interaction.

2. The through-type radio frequency microwave vector analysis device as described in claim 1, characterized in that, The RF front-end unit further includes an RF input port, a power divider, a local oscillator (LO) frequency synthesizer, and a load under test (UDT) port; the dual directional coupler is disposed between the RF input port and the UDT port. The power divider is connected to the local oscillator (LO) frequency synthesizer and is used to divide the local oscillator signal into a phase-coherent first local oscillator signal and a second local oscillator signal, which are respectively provided to the first down-conversion channel and the second down-conversion channel.

3. The through-type radio frequency microwave vector analysis device as described in claim 2, characterized in that, The first downconversion channel includes a first mixer, a first intermediate frequency filter, and a first intermediate frequency gain controllable amplifier connected in sequence. The RF input terminal of the first mixer is connected to the positive coupling port, and the local oscillator input terminal is connected to the first output terminal of the power divider. The second downconversion channel includes a second mixer, a second intermediate frequency filter, and a second intermediate frequency gain controllable amplifier connected in sequence. The RF input terminal of the second mixer is connected to the reverse coupling port, and the local oscillator input terminal is connected to the second output terminal of the power divider.

4. The through-type radio frequency microwave vector analysis device as described in claim 3, characterized in that, The first downconversion channel and the second downconversion channel adopt a zero intermediate frequency architecture or a fixed low intermediate frequency architecture.

5. The through-type radio frequency microwave vector analysis device as described in claim 1, characterized in that, The synchronous acquisition unit includes a first high-speed analog-to-digital converter and a second high-speed analog-to-digital converter; The first high-speed analog-to-digital converter is connected to the output terminal of the first down-conversion channel to perform analog-to-digital conversion on the signal output by the first down-conversion channel to obtain a first digital signal. The second high-speed analog-to-digital converter is connected to the output terminal of the second down-conversion channel to perform analog-to-digital conversion on the signal output by the second down-conversion channel to obtain the second digital signal; The first high-speed analog-to-digital converter and the second analog-to-digital converter synchronously transmit the first digital signal and the second digital signal to the digital signal processing unit, respectively.

6. The through-type radio frequency microwave vector analysis device as described in claim 1, characterized in that, The digital signal processing unit includes a field-programmable gate array (FPGA), which comprises the following functional parts: The digital downconversion and filtering section is used to perform digital downconversion and digital filtering on the first digital signal and the second digital signal. The FFT calculation part is used to perform a fast Fourier transform on the processed signal, converting the time-domain signal into a first complex signal sequence and a second complex signal sequence in the frequency domain. The vector separation operation section performs vector separation operations on the first complex signal sequence and the second complex signal sequence based on the calibration matrix to calculate the pure incident wave signal and reflected wave signal; The parameter calculation section is used to calculate the spectrum, power, reflection coefficient, impedance, and standing wave ratio parameters based on the incident wave signal and the reflected wave signal. The calibration parameter storage section is used to store the calibration matrix.

7. The through-type radio frequency microwave vector analysis device as described in claim 1, characterized in that, The control and interaction module includes: The microcontroller is used to coordinate the synchronous operation of the RF front-end, downconversion module, and digital acquisition and processing module, execute calibration process control, control RF switch switching, receive and process signals from the digital signal processing unit, and respond to user operation commands and control the working status of each module. The human-computer interaction unit is used to display measurement results and receive user operations.

8. A through-type radio frequency microwave vector analysis method, based on the through-type radio frequency microwave vector analysis device according to any one of claims 1-7, characterized in that, Includes the following steps: Radio frequency signals are transmitted in the radio frequency front-end unit, and at the same time, the forward coupling port and the reverse coupling port of the dual directional coupler couple out the first coupling signal and the second coupling signal, respectively. The first coupling signal and the second coupling signal are respectively input into the first down-conversion channel and the second down-conversion channel, and the first local oscillator signal and the second local oscillator signal are used to perform coherent down-conversion to obtain the first intermediate frequency signal and the second intermediate frequency signal. The first intermediate frequency signal and the second intermediate frequency signal are synchronously sampled by the synchronous acquisition unit to obtain the first digital signal and the second digital signal; The first digital signal and the second digital signal are processed to obtain a first complex signal sequence and a second complex signal sequence; Based on the calibration matrix, vector separation operations are performed on the first complex signal sequence and the second complex signal sequence to obtain pure incident wave signal and reflected wave signal, thereby obtaining the vector information of the radio frequency signal under actual working conditions.

9. The through-feed radio frequency microwave vector analysis method as described in claim 8, characterized in that, The calibration matrix is ​​obtained through the following steps: The load under test is connected to a matching load, and a frequency sweep measurement is performed across the entire measurement frequency band. The first set of complex signals is acquired and recorded at each frequency point. The load under test is connected to a short-circuited standard component, and a frequency sweep measurement is performed across the entire measurement frequency band. The second set of complex signals is collected and recorded at each frequency point. The load under test is connected to an open-circuit standard component, and a frequency sweep measurement is performed across the entire measurement frequency band. The third set of complex signals is collected and recorded at each frequency point. Based on three sets of complex signals and the known reflection coefficient of the standard component, solve for the four complex coefficients of the complex coefficient matrix at each frequency point; Calculate the inverse of the complex coefficient matrix, use the resulting inverse matrix as the calibration matrix, and store it.

10. The through-feed radio frequency microwave vector analysis method as described in claim 9, characterized in that, The vector separation operation on the first complex signal sequence and the second complex signal sequence based on the calibration matrix specifically includes: Establish a model relating the measured signal and the pure signal: Assuming the pure incident wave is F(t) and the reflected wave is R(t), and the measured first complex signal sequence and second complex signal sequence output from the first down-conversion channel and the second down-conversion channel are a(t) and b(t) respectively, then the relationship between them can be expressed as: a(t)=M_11×F(t)+M_12×R(t) (1); b(t)=M_21×F(t)+M_22×R(t) (2); Where M is a 2×2 complex coefficient matrix, and M_11, M_12, ​​M_21 and M_22 are the four complex coefficients of the complex coefficient matrix M; According to formulas (1) and (2), we can obtain: [F(t)] [a(t)] [R(t)]=inv(M)×[b(t)]; Here, inv(M) is the inverse of the complex coefficient matrix.

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