Dual port vector network analysis system

Abstract

The application discloses a kind of two-port vector network analysis systems, including radio frequency input module, for the power division processing of input excitation signal, obtain first excitation signal and second excitation signal, also for determining the excitation input signal of device under test according to second excitation signal;Local oscillator input module, for the power division processing of input local oscillator signal, obtain first local oscillator signal and second local oscillator signal, also for synthesizing local oscillator input signal according to first local oscillator signal, second local oscillator signal and first excitation signal;Vector network analysis module includes receiver circuit, receiver circuit is connected with the output end of local oscillator input module and device under test respectively, receiver circuit is used for the radio frequency signal generated by device under test according to excitation input signal and local oscillator input signal mixing frequency generation intermediate frequency signal, and data analysis is carried out to intermediate frequency signal, obtains the test data of device under test.The application can reduce the bandwidth of intermediate frequency signal, reduce development difficulty.

Description

Technical Field

[0001] This application relates to the field of measurement technology development, and in particular to a two-port vector network analysis system. Background Technology

[0002] In the current field of vector network analyzer technology, with the continuous miniaturization and integration of electronic devices and the increasing demand for high-precision measurement, traditional vector network analyzers face many challenges in terms of performance and application.

[0003] In a vector network analyzer, the input signal is usually a radio frequency (RF) signal with a wide frequency range and may not be fixed. In order to facilitate signal processing and analysis, the RF signal is usually mixed with the local oscillator signal by a mixer to obtain an intermediate frequency (IF) signal with a fixed frequency.

[0004] Therefore, existing vector network analyzers typically need to process a wide range of radio frequency signals, resulting in a broad range of acquired signals and a series of problems. On the one hand, the wide signal range requires handling interference from various frequency components during signal processing, increasing the complexity of signal processing and reducing measurement accuracy. On the other hand, in practical applications, such a wide signal range is often unnecessary. Acquiring a large number of unnecessary signals not only wastes system resources but also increases the burden on hardware design and software algorithms.

[0005] Meanwhile, traditional vector network analyzers often have a wide intermediate frequency (IF) bandwidth. While a wide IF bandwidth can quickly acquire more information in certain scenarios, it also introduces more noise and interference signals, which is extremely detrimental to applications requiring high-resolution, high-precision measurements. Furthermore, a wide IF bandwidth places extremely high demands on hardware performance, requiring high-performance filters, amplifiers, and other components to process wideband signals. This not only significantly increases hardware costs but also adds to the difficulty of research and development. The complex hardware design makes it difficult to guarantee the system's stability and reliability, making it prone to malfunctions during practical use and affecting the accuracy and consistency of measurement results.

[0006] Therefore, in order to solve the above problems, this application develops a novel two-port vector network analyzer. Summary of the Invention

[0007] To reduce the signal range acquired by the vector network analyzer and decrease the bandwidth of the intermediate frequency signal, this application provides a dual-port vector network analysis system.

[0008] A two-port vector network analysis system adopts the following technical solution:

[0009] A two-port vector network analysis system, connected to the device under test, includes:

[0010] The radio frequency input module is used to perform power division processing on the input excitation signal to obtain a first excitation signal and a second excitation signal, and is also used to determine the excitation input signal of the device under test based on the second excitation signal;

[0011] The local oscillator input module is used to perform power division processing on the input local oscillator signal to obtain a first local oscillator signal and a second local oscillator signal, and is also used to synthesize the local oscillator input signal based on the first local oscillator signal, the second local oscillator signal and the first excitation signal;

[0012] The vector network analysis module includes a receiver circuit, which is connected to the output of the local oscillator input module and the device under test (DUT). The receiver circuit is used to mix the radio frequency signal generated by the DUT based on the excitation input signal with the local oscillator input signal to generate an intermediate frequency (IF) signal, and to perform data analysis on the IF signal to obtain the test data of the DUT.

[0013] By adopting the above technical solution, through the power division processing of the excitation signal by the RF input module, and the processing and merging of the first excitation signal and the local oscillator signal by the local oscillator input module, vector network synthesis can be performed at a lower frequency to achieve the required frequency, reducing the range of acquired signals, effectively reducing signal interference, and improving the accuracy and processing efficiency of signal synthesis. The receiver circuit mixes the RF signal with the local oscillator input signal to generate an intermediate frequency signal, and performs data analysis on the intermediate frequency signal to obtain the test data of the device under test. This achieves high-precision and high-resolution signal measurement, significantly improving the measurement performance and reliability of the system.

[0014] Preferably, the local oscillator input module includes a local oscillator source circuit, which includes an RF local oscillator source and a first power divider. The input terminal of the first power divider is connected to the output terminal of the RF local oscillator source, and the local oscillator signal output by the RF local oscillator source is divided into a first local oscillator signal and a second local oscillator signal by average power division.

[0015] The local oscillator circuit also includes a first frequency multiplier, the input of which is connected to one output of the first power divider, to multiply the second local oscillator signal and output it.

[0016] By adopting the above technical solution, the local oscillator signal output from the RF local oscillator source in the local oscillator input module is divided into a first local oscillator signal and a second local oscillator signal by the first power divider, thereby achieving precise allocation of the local oscillator signal. The second local oscillator signal is then multiplied by the first frequency multiplier and output, effectively expanding the frequency range of the local oscillator signal, improving the flexibility and adaptability of the vector network analysis system, and better meeting the frequency requirements of different measurement scenarios.

[0017] Preferably, the local oscillator input module further includes a local oscillator frequency synthesis circuit, the input terminal of which is connected to the two output terminals of the local oscillator source circuit and the output terminal of the first excitation signal;

[0018] The local oscillator frequency synthesis circuit includes a first mixer. The input terminal of the first mixer is connected to the output terminal of the first local oscillator signal and the output terminal of the first excitation signal, respectively. The first mixer mixes the first local oscillator signal and the first excitation signal to obtain the local oscillator synthesized signal.

[0019] The local oscillator frequency synthesis circuit also includes a first radio frequency switch, which has two input ports and one output port. The output of the first mixer and the output of the second local oscillator signal are respectively connected to the two input ports of the first radio frequency switch.

[0020] The local oscillator frequency synthesis circuit also includes a second power divider, and the output port of the first radio frequency switch is connected to the input terminal of the second power divider;

[0021] The first radio frequency switch is used to connect the local oscillator synthesized signal to the second power divider, or the second local oscillator signal to the second power divider.

[0022] By adopting the above technical solution, the first local oscillator signal and the first excitation signal are mixed by the first mixer to obtain the synthesized local oscillator signal. This allows for the synthesis of local oscillator signals of specific frequencies according to actual needs, thereby achieving more accurate processing and analysis of radio frequency signals. The first RF switch provides flexibility in signal selection, allowing switching between different local oscillator signal sources based on measurement requirements. The second power divider performs power division processing on the connected signals before outputting the signal, adapting to the needs of a two-port network analyzer, satisfying the two-end testing requirements of the device under test, and further improving the stability and reliability of signal processing.

[0023] Preferably, the local oscillator frequency synthesis circuit further includes a third power divider and a fourth power divider;

[0024] One output terminal of the second power divider is connected to the input terminal of the third power divider, and the other output terminal of the second power divider is connected to the input terminal of the fourth power divider.

[0025] Both output terminals of the third power divider and both output terminals of the fourth power divider are connected to the receiver circuit.

[0026] By adopting the above technical solutions, the introduction of the third and fourth power dividers can further refine the distribution path of the local oscillator signal, realize the precise multi-path distribution of the local oscillator signal, not only improve the flexibility of signal distribution, but also enhance the stability of the system when processing complex signals, effectively reduce signal interference, and improve the measurement accuracy and reliability of the vector network analysis system.

[0027] Preferably, the radio frequency input module includes a radio frequency source circuit, which includes a radio frequency signal source and a fifth power divider. The input terminal of the fifth power divider is connected to the output terminal of the radio frequency signal source. The fifth power divider divides the excitation signal output by the radio frequency signal source into a first excitation signal and a second excitation signal by average power distribution.

[0028] The radio frequency source circuit also includes a second frequency multiplier. One output terminal of the fifth power divider is connected to the input terminal of the second frequency multiplier to perform frequency multiplication processing on the second excitation signal and output it.

[0029] The first excitation signal is output from the other output terminal of the fifth power divider.

[0030] By adopting the above technical solution, the fifth power divider effectively distributes the excitation signal, ensuring the stability and uniformity of signal transmission. The second frequency multiplier performs frequency multiplication on the second excitation signal and outputs it, improving the controllability of the signal frequency range and meeting the needs of different measurement scenarios.

[0031] Preferably, the radio frequency input module further includes a radio frequency processing circuit, the input terminal of which is connected to the output terminal of the second excitation signal;

[0032] The radio frequency processing circuit includes a second radio frequency switch, which has one input port and two output ports. The two output ports of the second radio frequency switch are respectively connected to two test ports of the device under test through the receiver circuit. When the second radio frequency switch is connected to one of the test ports of the device under test, the second excitation signal is input to the device under test as an excitation input signal.

[0033] By adopting the above technical solution, the second RF switch can selectively conduct the second excitation signal to different test ports of the device under test according to actual needs, thereby realizing independent testing of different ports and improving the flexibility and efficiency of testing.

[0034] Preferably, the receiver circuit includes a first receiving port and a second receiving port, wherein the first receiving port is connected to a first test port of the device under test, and the second receiving port is connected to a second test port of the device under test;

[0035] The receiver circuit further includes a first directional coupler and a first mixer unit, wherein the first directional coupler is connected to the first receiving port and the input terminal of the first mixer unit, respectively.

[0036] The first mixing unit includes a second mixer and a third mixer. The two input terminals of the second mixer are respectively connected to the first output terminal of the first directional coupler and the first output terminal of the third power divider. The two input terminals of the third mixer are respectively connected to the second output terminal of the first directional coupler and the second output terminal of the third power divider.

[0037] The receiver circuit further includes a first signal processing unit, an analog-to-digital converter, and a digital signal processor. The output terminals of the second mixer and the third mixer are respectively connected to the first signal processing unit. The output terminal of the first signal processing unit is connected to the analog-to-digital converter, and the analog-to-digital converter is connected to the digital signal processor.

[0038] By adopting the above technical solution, two receiving ports are connected to the two test ports of the device under test, respectively, which can simultaneously acquire the signal responses at both ends of the device under test, improving test efficiency and data integrity. The first mixing unit mixes the two signals output from the first directional coupler with the local oscillator signal output from the third power divider to generate an intermediate frequency signal, effectively reducing interference from high-frequency signals and improving signal resolution and measurement accuracy. Through multi-stage signal processing, the measurement accuracy, stability, and adaptability of the vector network analysis system are significantly improved, meeting the requirements for high-precision measurement.

[0039] Preferably, the first signal processing unit includes a third radio frequency switch, a fourth radio frequency switch, a fifth radio frequency switch, and a sixth radio frequency switch;

[0040] The output terminal of the second mixer is connected to the input terminal of the third RF switch, the output terminal of the third mixer is connected to the input terminal of the fifth RF switch, and the output terminals of the fourth RF switch and the sixth RF switch are respectively connected to the analog-to-digital converter.

[0041] A third frequency multiplier is connected between the third RF switch and the fourth RF switch, and a fourth frequency multiplier is connected between the fifth RF switch and the sixth RF switch.

[0042] By adopting the above technical solutions, the third and fourth RF switches can selectively transmit the output signal of the second mixer to the analog-to-digital converter after processing by the third frequency multiplier, thereby realizing flexible control of the signal frequency and improving the accuracy and adaptability of signal processing; the fifth and sixth RF switches can selectively transmit the output signal of the third mixer to the analog-to-digital converter after processing by the fourth frequency multiplier, further enhancing the flexibility of signal processing, reducing unnecessary signal interference, and improving the accuracy of measurement.

[0043] Preferably, the receiver circuit further includes a second directional coupler, a second mixer unit, and a second signal processing unit, wherein the second directional coupler is connected to the second receiving port and the input terminal of the second mixer unit, respectively.

[0044] The second mixing unit includes a fourth mixer and a fifth mixer. The two input terminals of the fourth mixer are respectively connected to the first output terminal of the second directional coupler and the first output terminal of the fourth power divider. The two input terminals of the fifth mixer are respectively connected to the second output terminal of the second directional coupler and the second output terminal of the fourth power divider.

[0045] The output terminals of the fourth mixer and the fifth mixer are respectively connected to the second signal processing unit, and the output terminal of the second signal processing unit is connected to the analog-to-digital converter.

[0046] By adopting the above technical solutions, the fourth and fifth mixers achieve precise mixing of radio frequency signals and local oscillator signals, thereby generating stable intermediate frequency signals and further improving the resolution of signal analysis. The second signal processing unit processes the intermediate frequency signals output by the fourth and fifth mixers and then transmits them to the analog-to-digital converter, ensuring the efficiency and accuracy of signal conversion from the analog domain to the digital domain, and ultimately improving the measurement accuracy and stability of the entire system.

[0047] 10 Preferably, the second signal processing unit includes a seventh radio frequency switch, an eighth radio frequency switch, a ninth radio frequency switch, and a tenth radio frequency switch;

[0048] The output of the fourth mixer is connected to the input of the seventh RF switch, the output of the fifth mixer is connected to the input of the ninth RF switch, and the outputs of the eighth and tenth RF switches are respectively connected to the analog-to-digital converter.

[0049] A fifth frequency multiplier is connected between the seventh and eighth RF switches, and a sixth frequency multiplier is connected between the ninth and tenth RF switches.

[0050] By adopting the above technical solution, the setting of the seventh to tenth RF switches enables flexible switching and processing of the output signals of the fourth and fifth mixers; the fifth and sixth frequency multipliers are connected between the RF switches respectively, which can further multiply the signals, thereby expanding the frequency range of the signals, improving the flexibility and adaptability of signal processing, enabling the system to better cope with the signal requirements of different frequency components, and improving the measurement accuracy and reliability of the vector network analysis system.

[0051] In summary, this application includes at least one of the following beneficial technical effects:

[0052] 1. This application performs power division processing on the excitation signal through the radio frequency input module and combines the local oscillator signal synthesis technology of the local oscillator input module to accurately generate excitation input signals and local oscillator input signals that are adapted to the device under test, effectively reducing unnecessary broadband signal processing and reducing system complexity and resource waste.

[0053] 2. This application avoids the noise and interference problems caused by traditional wide intermediate frequency bandwidth designs by selectively multiplying the intermediate frequency signal and generating an intermediate frequency signal by mixing the radio frequency signal and the local oscillator signal in the receiver circuit, and significantly improves the measurement accuracy and applicability.

[0054] 3. This application improves the adaptability and stability of the system and reduces hardware costs and R&D difficulty by using a modular design for the RF input and local oscillator input structures, combined with flexible frequency multiplication and mixing processing. Attached Figure Description

[0055] Figure 1 This is a schematic diagram of the radio frequency source circuit in this embodiment;

[0056] Figure 2 This is a schematic diagram of the radio frequency processing circuit in this embodiment;

[0057] Figure 3 This is a schematic diagram of the local oscillator circuit in this embodiment;

[0058] Figure 4 This is a schematic diagram of the local oscillator frequency synthesis circuit in this embodiment;

[0059] Figure 5 This is a schematic diagram of the receiver circuit in this embodiment;

[0060] Explanation of reference numerals in the attached figures:

[0061] 1. First power divider; 2. First mixer; 3. First RF switch; 4. Second power divider; 5. Third power divider; 6. Fourth power divider; 7. Fifth power divider; 8. Second RF switch; 9. First directional coupler; 10. Second mixer; 11. Third mixer; 12. Third RF switch; 13. Fourth RF switch; 14. Fifth RF switch; 15. Sixth RF switch; 16. Third frequency multiplier; 17. Fourth frequency multiplier; 18. Second directional coupler; 19. Fourth mixer; 20. Fifth mixer; 21. Seventh RF switch; 22. Eighth RF switch; 23. Ninth RF switch; 24. Tenth RF switch; 25. Fifth frequency multiplier; 26. Sixth frequency multiplier; 27. First frequency multiplier; 28. Second frequency multiplier. Detailed Implementation

[0062] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be further described in detail below with reference to the accompanying drawings.

[0063] This application provides a dual-port vector network analysis system connected to the device under test (DUT), including: a local oscillator input module, an RF input module, and a vector network analysis module.

[0064] Among them, the radio frequency input module, such as Figure 1 and Figure 2 As shown, it is used to perform power division processing on the input excitation signal to obtain a first excitation signal and a second excitation signal, and is also used to determine the excitation input signal of the device under test based on the second excitation signal.

[0065] In a specific feasible approach, such as Figure 1 As shown, the RF input module includes an RF source circuit, which includes an RF signal source RF and a fifth power divider 7. The input terminal of the fifth power divider 7 is connected to the output terminal of the RF signal source. The fifth power divider 7 divides the excitation signal output by the RF signal source into a first excitation signal and a second excitation signal by average power distribution.

[0066] The RF source circuit also includes a second frequency multiplier 28. One output terminal of the fifth power divider 7 is connected to the input terminal of the second frequency multiplier 28 to multiply the second excitation signal to obtain a signal with a frequency of 2 times RF, labeled RF2, and output it.

[0067] The first excitation signal is output from the other output terminal of the fifth power divider 7.

[0068] In a specific feasible approach, such as Figure 1As shown, an output matching network and an adjustable filter network are connected sequentially between the RF signal source RF and the fifth power divider 7. The output matching network is connected to the RF signal source to achieve impedance matching between the RF signal source and subsequent circuits. By adjusting the impedance, the power output by the signal source can be efficiently transmitted to the next stage circuit, reducing signal reflection and improving signal transmission efficiency. The adjustable filter network is connected to the output matching network and can filter out stray components and unwanted frequency components in the excitation signal, making the output excitation signal purer.

[0069] In a specific feasible approach, such as Figure 1 As shown, an RF signal amplifier and a filter network are also connected in the output branch of the second excitation signal. The second excitation signal first passes through the RF signal amplifier circuit to increase the power amplitude of the second excitation signal to meet the requirements of subsequent processing or transmission. After frequency multiplication, the signal passes through a filter network to further filter out spurious signals and unwanted frequency components generated during the frequency multiplication process, making the output second excitation signal with frequency RF2 purer.

[0070] In the output branch of the first excitation signal, there is also an RF signal amplifier and a filter network, which serve the same purpose as above and will not be described again here.

[0071] In a specific feasible approach, such as Figure 2 As shown, the RF input module also includes an RF processing circuit, the input terminal of which is connected to the output terminal of the second excitation signal.

[0072] The radio frequency processing circuit includes a second radio frequency switch 8, which includes one input port and two output ports. The second radio frequency switch 8 is a single-pole double-throw switch.

[0073] The two output ports of the second RF switch 8 are connected to the two test ports of the device under test through the receiver circuit. When the second RF switch 8 is connected to one of the test ports of the device under test, the second excitation signal is input to the device under test as an excitation input signal.

[0074] like Figure 2 As shown, when the second RF switch 8 is connected to the upper branch, the excitation input signal input to the device under test is RFP2. When the second RF switch 8 is connected to the lower branch, the excitation input signal input to the device under test is RFP1. These two excitation input signals will be input to two different test ports of the device under test to meet the dual-port test requirements.

[0075] In a specific feasible approach, such as Figure 2As shown, in the radio frequency processing circuit, the input terminal of the second radio frequency switch 8 is also connected to a filter network, which is used to filter the input second excitation signal RF2. By filtering out spurious frequency components, noise and other unwanted signal components in the signal, the output signal is made purer.

[0076] In a specific feasible approach, such as Figure 2 As shown, each of the two output branches of the second RF switch 8 is connected to a filter network and an RF signal amplifier. After being selected by the second RF switch 8, the second excitation signal first passes through a filter network for further filtering and purification, and then enters the RF signal amplification module. The RF signal amplification module amplifies the signal power to increase its strength, and finally outputs the excitation input signal RFP1 or RFP2.

[0077] Local oscillator input module, such as Figure 3 and Figure 4 As shown, it is used to perform power division processing on the input local oscillator signal to obtain the first local oscillator signal and the second local oscillator signal, and is also used to synthesize the local oscillator input signal based on the first local oscillator signal, the second local oscillator signal and the first excitation signal.

[0078] In a specific feasible approach, such as Figure 3 As shown, the local oscillator input module includes a local oscillator source circuit, which includes an RF local oscillator source LO and a first power divider 1. The input terminal of the first power divider 1 is connected to the output terminal of the RF local oscillator source, and the local oscillator signal output by the RF local oscillator source is divided into a first local oscillator signal and a second local oscillator signal by average power distribution.

[0079] The local oscillator circuit also includes a first frequency multiplier 27. The input terminal of the first frequency multiplier 27 is connected to one output terminal of the first power divider 1 to perform frequency multiplication on the second local oscillator signal, thereby obtaining a signal with a frequency of 2 times LO, labeled as LO2, and outputting it.

[0080] In a specific feasible approach, such as Figure 3 As shown, an output matching network and an adjustable filter network are connected sequentially between the RF local oscillator LO and the fifth power divider 7. The functions of the output matching network and the adjustable filter network are the same as those in the RF source circuit described above, and will not be repeated here.

[0081] In a specific feasible approach, such as Figure 3 As shown, an RF signal amplifier and a filter network are also connected in the output branch of the second local oscillator signal;

[0082] In the output branch of the first local oscillator signal, there is also a radio frequency signal amplifier and a filter network connected, which function the same as the radio frequency source circuit described above, and will not be described again here.

[0083] In a specific feasible approach, such as Figure 4 As shown, the local oscillator input module also includes a local oscillator frequency synthesis circuit. The input terminal of the local oscillator frequency synthesis circuit is connected to the two output terminals of the local oscillator source circuit and the output terminal of the first excitation signal RF1.

[0084] Specifically, the local oscillator frequency synthesis circuit includes a first mixer 2. The input terminal of the first mixer 2 is connected to the output terminal of the first local oscillator signal LO1 and the output terminal of the first excitation signal RF1, respectively. The first mixer 2 mixes the first local oscillator signal and the first excitation signal to obtain the local oscillator synthesized signal.

[0085] In this embodiment, the first mixer 2 is an up-conversion mixer, and the frequency of the local oscillator synthesized signal obtained by the first mixer 2 is the sum of the frequencies of the first local oscillator signal LO1 and the first excitation signal RF1.

[0086] The local oscillator frequency synthesis circuit also includes a first radio frequency switch 3, which has two input ports and one output port. The first radio frequency switch 3 is a single-pole double-throw switch.

[0087] The output terminal of the first mixer 2 and the output terminal of the second local oscillator signal are respectively connected to the two input ports of the first radio frequency switch 3. Therefore, the two input terminals of the first radio frequency switch 3 are respectively connected to the local oscillator synthesized signal and the second local oscillator signal LO2.

[0088] The local oscillator frequency synthesis circuit also includes a second power divider 4, and the output port of the first RF switch 3 is connected to the input terminal of the second power divider 4;

[0089] The first RF switch 3 is used to connect the local oscillator synthesized signal to the second power divider 4, or the second local oscillator signal to the second power divider 4. This structure allows the system to select the frequency of the local oscillator input signal.

[0090] In a specific feasible approach, such as Figure 4 As shown, the local oscillator frequency synthesis circuit also includes a third power divider 5 and a fourth power divider 6;

[0091] One output terminal of the second power divider 4 is connected to the input terminal of the third power divider 5, and the two ends of the third power divider 5 output signals A1 and B1 respectively; the other output terminal of the second power divider 4 is connected to the input terminal of the fourth power divider 6, and the two ends of the fourth power divider 6 output signals A2 and B2 respectively.

[0092] The two outputs of the third power divider 5 and the two outputs of the fourth power divider 6 are all connected to the receiver circuit. The A1 and B1 outputs of the third power divider 5 and the A2 and B2 outputs of the fourth power divider 6 are used as the local oscillator input signals of two different ports of the receiver.

[0093] In a specific feasible approach, such as Figure 4 As shown, the local oscillator frequency synthesis circuit also includes an upper sideband filter network. This upper sideband filter network is located between the first RF switch 3 and the second power divider 4, and it filters the local oscillator signal selected by the first RF switch 3. It filters out unwanted frequency components, retaining only the upper sideband signal. In RF communication, the upper and lower sidebands are different frequency components generated after mixing. Filtering to select specific sideband signals helps improve signal quality and reduce interference.

[0094] In a specific feasible approach, such as Figure 4 As shown, a filter network and an RF signal amplifier are connected sequentially between the second power divider 4 and the third power divider 5. The local oscillator signal split from the second power divider 4 first passes through a filter network to further filter out spurious components in the signal, and then enters the RF signal amplifier to amplify the signal power to meet the requirements of subsequent processing or transmission. Finally, the local oscillator input signals A1 and B1 are output.

[0095] In a specific feasible approach, such as Figure 4 As shown, a filter network and an RF signal amplifier are connected sequentially between the second power divider 4 and the fourth power divider 6, and finally output the local oscillator input signals A2 and B2. Their functions are the same as above, and will not be repeated here.

[0096] Local oscillator input signals A1 and B1, and local oscillator input signals A2 and B2 are connected to the two ends of the receiver circuit, respectively, serving as their respective local oscillator input signals for two-ended vector network analysis.

[0097] Vector network analysis module, such as Figure 5 As shown, the device includes a receiver circuit, which is connected to the output of the local oscillator input module and the device under test (DUT). The receiver circuit is used to mix the radio frequency signal generated by the DUT based on the excitation input signal with the local oscillator input signal to generate an intermediate frequency (IF) signal, and to perform data analysis on the IF signal to obtain the test data of the DUT.

[0098] In one feasible embodiment, the receiver circuit includes a first receiving port PORT1 and a second receiving port PORT2, the first receiving port being connected to a first test port of the device under test, and the second receiving port being connected to a second test port of the device under test.

[0099] In one feasible embodiment, for the first receiving port side of the receiver circuit: the receiver circuit includes a first directional coupler 9 and a first mixer unit, the first directional coupler 9 being connected to the first receiving port and the input of the first mixer unit, respectively.

[0100] The first mixing unit includes a second mixer 10 and a third mixer 11. The two input terminals of the second mixer 10 are respectively connected to the first output terminal of the first directional coupler 9 and the first output terminal of the third power divider 5. The two input terminals of the third mixer 11 are respectively connected to the second output terminal of the first directional coupler 9 and the second output terminal of the third power divider 5.

[0101] In this embodiment, the excitation input signal RFP1 is input to the device under test (DUT) through the first test port. After the excitation input signal acts on the DUT, it generates reflected and transmitted signals, which are the radio frequency (RF) signals received by the receiver. Subsequently, the first mixer unit in the receiver circuit mixes the received RF signals with the local oscillator signal to obtain intermediate frequency (IF) signals IFA1 and IFB1.

[0102] For example, the excitation input signal is input to the device under test through PORT1 and the first test port. The reflected signal of the device under test is separated by the first directional coupler 9 and then enters the second mixer 10 and the third mixer 11 in the first mixing unit to mix with the local oscillator signal to obtain the intermediate frequency signal.

[0103] The receiver circuit also includes a first signal processing unit, an analog-to-digital converter (ADC), and a digital signal processor (DSP). The outputs of the second mixer 10 and the third mixer 11 are respectively connected to the first signal processing unit. The output of the first signal processing unit is connected to the ADC, and the ADC is connected to the DSP.

[0104] In one feasible embodiment, the first signal processing unit includes a third RF switch 12, a fourth RF switch 13, a fifth RF switch 14, and a sixth RF switch 15, all of which are single-pole double-throw switches. The third RF switch 12 and the fifth RF switch 14 each include one input port and two output ports, while the fourth RF switch 13 and the sixth RF switch 15 each include two input ports and one output port.

[0105] The output of the second mixer 10 is connected to the input port of the third RF switch 12, and the output of the third mixer 11 is connected to the input port of the fifth RF switch 14.

[0106] The output terminals of the fourth RF switch 13 and the sixth RF switch 15 are respectively connected to the analog-to-digital converter;

[0107] A third frequency multiplier 16 is connected between the third RF switch 12 and the fourth RF switch 13. That is, one of the two output branches of the third RF switch 12 is connected to the third frequency multiplier 16, which can multiply the intermediate frequency signal IFA1 by 2.

[0108] A fourth frequency multiplier 17 is connected between the fifth RF switch 14 and the sixth RF switch 15. That is, one of the two output branches of the fifth RF switch 14 is connected to the fourth frequency multiplier 17, which can multiply the intermediate frequency signal IFB1 by 2.

[0109] In one feasible embodiment, a low-pass filter (LPF) is connected between the second mixer 10 and the third RF switch 12, and between the third mixer 11 and the fifth RF switch 14, respectively. This LPF is used to filter out high-frequency spurious signals and noise generated during the mixing process, allowing only intermediate frequency signals below a specific frequency to pass through, thereby improving the purity of the signal.

[0110] In one feasible implementation, to ensure phase accuracy, the system architecture is designed to be globally symmetrical, meaning that the second receiving port side is symmetrical to the first receiving port side.

[0111] Specifically, the receiver circuit includes a second directional coupler 18, a second mixing unit, and a second signal processing unit. The second directional coupler 18 is connected to the second receiving port and the input terminal of the second mixing unit, respectively.

[0112] The second mixing unit includes a fourth mixer 19 and a fifth mixer 20. The two input terminals of the fourth mixer 19 are respectively connected to the first output terminal of the second directional coupler 18 and the first output terminal of the fourth power divider 6. The two input terminals of the fifth mixer 20 are respectively connected to the second output terminal of the second directional coupler 18 and the second output terminal of the fourth power divider 6.

[0113] In this embodiment, the excitation input signal RFP2 is input to the device under test (DUT) through the second test port. After the excitation input signal acts on the DUT, it generates reflected and transmitted signals, which are the radio frequency (RF) signals received by the receiver. Subsequently, the second mixer unit in the receiver circuit mixes the received RF signals with the local oscillator signal to obtain intermediate frequency (IF) signals IFA2 and IFB2.

[0114] For example, the excitation input signal is input to the device under test through PORT2 and the second test port. The reflected signal of the device under test is separated by the second directional coupler 18 and then enters the fourth mixer 19 and the fifth mixer 20 in the second mixing unit to mix with the local oscillator signal to obtain the intermediate frequency signal.

[0115] The output terminals of the fourth mixer 19 and the fifth mixer 20 are respectively connected to the second signal processing unit, and the output terminal of the second signal processing unit is connected to the analog-to-digital converter.

[0116] In one feasible embodiment, the second signal processing unit includes a seventh RF switch 21, an eighth RF switch 22, a ninth RF switch 23, and a tenth RF switch 24, all of which are single-pole double-throw switches. The seventh RF switch 21 and the ninth RF switch 23 each include one input port and two output ports, while the eighth RF switch 22 and the tenth RF switch 24 each include two input ports and one output port.

[0117] The output of the fourth mixer 19 is connected to the input of the seventh RF switch 21, the output of the fifth mixer 20 is connected to the input of the ninth RF switch 23, and the outputs of the eighth RF switch 22 and the tenth RF switch 24 are respectively connected to the analog-to-digital converter.

[0118] A fifth frequency multiplier 25 is connected between the seventh RF switch 21 and the eighth RF switch 22. That is, one of the two output branches of the seventh RF switch 21 is connected to the fifth frequency multiplier 25, which can multiply the intermediate frequency signal IFA2 by 2.

[0119] A sixth frequency multiplier 26 is connected between the ninth RF switch 23 and the tenth RF switch 24. That is, one of the two output branches of the ninth RF switch 23 is connected to the sixth frequency multiplier 26, which can multiply the intermediate frequency signal IFB2 by 2.

[0120] In one feasible embodiment, low-pass filters (LPFs) are connected between the fourth mixer 19 and the seventh RF switch 21, and between the fifth mixer 20 and the ninth RF switch 23, respectively. These filters are used to remove high-frequency spurious signals and noise generated during the mixing process, allowing only intermediate frequency signals below a specific frequency to pass through, thereby improving the purity of the signal.

[0121] In another feasible specific approach, such as Figure 1 and Figure 3 Assume that a radio frequency (RF) signal source circuit is developed to generate RF signals ranging from 50MHz to 4GHz. That is, RF1 has a range of 50MHz to 4GHz, RF2 is equal to 2*RF1, and RF2 has a range of 100MHz to 8GHz. LO1 has a range of 50MHz to 4GHz, and LO2 is equal to 2*LO1, and LO2 has a range of 100MHz to 8GHz.

[0122] like Figure 2 After filtering and power splitting the RF2 link, the output signal is sent to... Figure 5 In the link, a radio frequency signal source ranging from 100MHz to 8GHz is formed.

[0123] like Figure 4The key signal mixing operation is performed. After RF1 and LO1 are mixed, signals in upper and lower frequency bands are formed. The lower frequency band signal is filtered out, and the upper frequency band (RF1+LO1) signal is extracted. Here, the signal of LO2 is switched and controlled. Within the range of 100MHz~8GHz, it is divided into two frequency bands. When the frequency is lower than 4GHz, the first RF switch 3 switches to the link of the local oscillator synthesized signal; when the frequency is higher than 4GHz, the first RF switch 3 switches to the link of the second local oscillator signal LO2.

[0124] The local oscillator input signal, after passing through a filter network and a power divider, enters the receiver circuit of this system to participate in mixing.

[0125] In the receiver link of a vector network analyzer, it is necessary to ensure that the phase and amplitude of the link are symmetrical, such as... Figure 5 The radio frequency signal source passes through the directional coupler to obtain coupled and reflected signals. The receiver circuit performs link mixing with the signal from the directional coupler under the same phase and amplitude conditions, thereby obtaining 10MHz intermediate frequency signals A1, B1, A2, and B2.

[0126] An analog-to-digital converter is used to acquire these four sets of signals and transmit them to an FPGA or DSP for data analysis and Fourier transform.

[0127] The specific calculation is as follows: When the frequency is below 4GHz, the signals participating in the mixing of the directional coupler in the receiver circuit are RF2 and RF1+LO1. The intermediate frequency signal after mixing is IF1=RF2-(RF1+LO1)=RF1-LO1. When the frequency is above 4GHz, the signals participating in the mixing of the directional coupler in the receiver link are RF2 and LO2. The intermediate frequency signal after mixing is IF2=RF2-LO2=2*RF1-2*LO1=2*IF1. Therefore, in the receiver, by symmetrically designing the intermediate frequency signal again and multiplying the frequency in the band below 4GHz, the same IF signal can be maintained.

[0128] Using the above technical solution, an 8GHz dual-port vector network analyzer was designed. Compared with traditional 8GHz dual-port network analyzers, the test data is consistent. Furthermore, the onboard RF signal source extends to 4GHz, significantly reducing the development difficulty of a single board. Moreover, due to the narrower intermediate frequency bandwidth, the power of noise and interference signals entering the system is correspondingly reduced, improving the signal-to-noise ratio, measurement accuracy, and stability.

[0129] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A two-port vector network analysis system, connected to the device under test, characterized in that, include: The radio frequency input module is used to perform power division processing on the input excitation signal to obtain a first excitation signal and a second excitation signal, and is also used to determine the excitation input signal of the device under test based on the second excitation signal; The local oscillator input module is used to perform power division processing on the input local oscillator signal to obtain a first local oscillator signal and a second local oscillator signal, and is also used to synthesize the local oscillator input signal based on the first local oscillator signal, the second local oscillator signal and the first excitation signal; Specifically, the local oscillator input module includes a local oscillator frequency synthesis circuit, which includes a first mixer (2). The input terminal of the first mixer (2) is connected to the output terminal of the first local oscillator signal and the output terminal of the first excitation signal, respectively. The first mixer (2) mixes the first local oscillator signal and the first excitation signal to obtain a local oscillator synthesized signal. The local oscillator frequency synthesis circuit also includes a first radio frequency switch (3); the first radio frequency switch (3) includes two input ports and one output port. The two input terminals of the first radio frequency switch (3) are respectively connected to the local oscillator synthesized signal and the second local oscillator signal, and are used to select the frequency of the local oscillator input signal. The vector network analysis module includes a receiver circuit, which is connected to the output of the local oscillator input module and the device under test (DUT). The receiver circuit is used to mix the radio frequency signal generated by the DUT based on the excitation input signal with the local oscillator input signal to generate an intermediate frequency (IF) signal, and to perform data analysis on the IF signal to obtain the test data of the DUT.

2. The two-port vector network analysis system according to claim 1, characterized in that: The local oscillator input module further includes a local oscillator source circuit, which includes a radio frequency local oscillator source and a first power divider (1). The input terminal of the first power divider (1) is connected to the output terminal of the radio frequency local oscillator source, and the local oscillator signal output by the radio frequency local oscillator source is divided into a first local oscillator signal and a second local oscillator signal by average power. The input terminal of the local oscillator frequency synthesis circuit is connected to the two output terminals of the local oscillator source circuit and the output terminal of the first excitation signal. The local oscillator circuit also includes a first frequency multiplier (27), the input of which is connected to one output of the first power divider (1), and the second local oscillator signal is multiplied and output.

3. The two-port vector network analysis system according to claim 2, characterized in that: The local oscillator frequency synthesis circuit also includes a second power divider (4), and the output port of the first radio frequency switch (3) is connected to the input terminal of the second power divider (4); The first radio frequency switch (3) is used to connect the connection path between the local oscillator synthesized signal and the second power divider (4), or the connection path between the second local oscillator signal and the second power divider (4); The local oscillator frequency synthesis circuit also includes a third power divider (5) and a fourth power divider (6). One output terminal of the second power divider (4) is connected to the input terminal of the third power divider (5), and the other output terminal of the second power divider (4) is connected to the input terminal of the fourth power divider (6). Both output terminals of the third power divider (5) and both output terminals of the fourth power divider (6) are connected to the receiver circuit.

4. The two-port vector network analysis system according to claim 1, characterized in that: The radio frequency input module includes a radio frequency source circuit, which includes a radio frequency signal source and a fifth power divider (7). The input terminal of the fifth power divider (7) is connected to the output terminal of the radio frequency signal source. The fifth power divider (7) divides the excitation signal output by the radio frequency signal source into a first excitation signal and a second excitation signal. The radio frequency source circuit also includes a second frequency multiplier (28). One output terminal of the fifth power divider (7) is connected to the input terminal of the second frequency multiplier (28) to perform frequency multiplication on the second excitation signal and output it. The first excitation signal is output from the other output terminal of the fifth power divider (7).

5. The two-port vector network analysis system according to claim 4, characterized in that: The radio frequency input module further includes a radio frequency processing circuit, the input terminal of which is connected to the output terminal of the second excitation signal; The radio frequency processing circuit includes a second radio frequency switch (8), which includes an input port and two output ports. The two output ports of the second radio frequency switch (8) are respectively connected to two test ports of the device under test through the receiver circuit. When the second radio frequency switch (8) is connected to one of the test ports of the device under test, the second excitation signal is input to the device under test as an excitation input signal.

6. The two-port vector network analysis system according to claim 3, characterized in that: The receiver circuit includes a first receiving port and a second receiving port. The first receiving port is connected to a first test port of the device under test, and the second receiving port is connected to a second test port of the device under test. The receiver circuit further includes a first directional coupler (9) and a first mixer unit, wherein the first directional coupler (9) is connected to the first receiving port and the input terminal of the first mixer unit, respectively. The first mixing unit includes a second mixer (10) and a third mixer (11). The two input terminals of the second mixer (10) are respectively connected to the first output terminal of the first directional coupler (9) and the first output terminal of the third power divider (5). The two input terminals of the third mixer (11) are respectively connected to the second output terminal of the first directional coupler (9) and the second output terminal of the third power divider (5). The receiver circuit further includes a first signal processing unit, an analog-to-digital converter, and a digital signal processor. The output of the second mixer (10) and the output of the third mixer (11) are respectively connected to the first signal processing unit. The output of the first signal processing unit is connected to the analog-to-digital converter, and the analog-to-digital converter is connected to the digital signal processor.

7. The two-port vector network analysis system according to claim 6, characterized in that: The first signal processing unit includes a third radio frequency switch (12), a fourth radio frequency switch (13), a fifth radio frequency switch (14), and a sixth radio frequency switch (15). The output of the second mixer (10) is connected to the input of the third RF switch (12), the output of the third mixer (11) is connected to the input of the fifth RF switch (14), and the outputs of the fourth RF switch (13) and the sixth RF switch (15) are respectively connected to the analog-to-digital converter. A third frequency multiplier (16) is connected between the third RF switch (12) and the fourth RF switch (13), and a fourth frequency multiplier (17) is connected between the fifth RF switch (14) and the sixth RF switch (15).

8. The two-port vector network analysis system according to claim 6, characterized in that: The receiver circuit further includes a second directional coupler (18), a second mixing unit, and a second signal processing unit. The second directional coupler (18) is connected to the second receiving port and the input terminal of the second mixing unit, respectively. The second mixing unit includes a fourth mixer (19) and a fifth mixer (20). The two input terminals of the fourth mixer (19) are respectively connected to the first output terminal of the second directional coupler (18) and the first output terminal of the fourth power divider (6). The two input terminals of the fifth mixer (20) are respectively connected to the second output terminal of the second directional coupler (18) and the second output terminal of the fourth power divider (6). The output terminals of the fourth mixer (19) and the fifth mixer (20) are respectively connected to the second signal processing unit, and the output terminal of the second signal processing unit is connected to the analog-to-digital converter.

9. The two-port vector network analysis system according to claim 8, characterized in that: The second signal processing unit includes a seventh radio frequency switch (21), an eighth radio frequency switch (22), a ninth radio frequency switch (23), and a tenth radio frequency switch (24). The output of the fourth mixer (19) is connected to the input of the seventh radio frequency switch (21), the output of the fifth mixer (20) is connected to the input of the ninth radio frequency switch (23), and the outputs of the eighth radio frequency switch (22) and the tenth radio frequency switch (24) are respectively connected to the analog-to-digital converter. A fifth frequency multiplier (25) is connected between the seventh RF switch (21) and the eighth RF switch (22), and a sixth frequency multiplier (26) is connected between the ninth RF switch (23) and the tenth RF switch (24).

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