Dual-port vector network analysis system

Abstract

The invention discloses a dual-port vector network analysis system, and the system comprises a radio frequency input module which is used for carrying out the power division of an input excitation signal, obtaining a first excitation signal and a second excitation signal, and determining an excitation input signal of a tested device according to the second excitation signal; the local oscillator input module is used for performing power division processing on an input local oscillator signal to obtain a first local oscillator signal and a second local oscillator signal, and is also used for synthesizing a local oscillator input signal according to the first local oscillator signal, the second local oscillator signal and the first excitation signal; the vector network analysis module comprises a receiver circuit, the receiver circuit is respectively connected with the output end of the local oscillator input module and the tested equipment, and the receiver circuit is used for mixing a radio frequency signal generated by the tested equipment according to the excitation input signal with the local oscillator input signal to generate an intermediate frequency signal and carrying out data analysis on the intermediate frequency signal; and obtaining test data of the tested equipment. The bandwidth of the intermediate frequency signal can be reduced, and the research and development difficulty is reduced.

Description

Technical Field

[0001] The present application relates to the field of measurement technology development, and in particular to a dual-port vector network analysis system. Background Art

[0002] In the current field of vector network analyzer technology, with the continuous miniaturization and integration of electronic devices and the growing demand for high-precision measurements, traditional vector network analyzers face many challenges in performance and application. In a vector network analyzer, the input signal is usually a radio frequency (RF) signal, which has 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 through a mixer to obtain an intermediate frequency (IF) signal with a fixed frequency.

[0003] Therefore, existing vector network analyzers usually need to process a wider range of RF signals, which results in a wide range of signals collected, bringing a series of problems. On the one hand, the wide signal range requires the signal processing process to deal with interference from various frequency components, which increases the complexity of signal processing and reduces the accuracy of measurement. On the other hand, in actual application scenarios, such a wide signal range is not required in many cases. A large amount of unnecessary signal collection not only wastes system resources, but also increases the burden on hardware design and software algorithms. At the same time, the IF bandwidth of traditional vector network analyzers is often wide. Although the wide IF bandwidth can quickly obtain more information in some scenarios, it also introduces more noise and interference signals, which is extremely unfavorable for application scenarios that require high-resolution and high-precision measurements. Moreover, the wide IF bandwidth has extremely high performance requirements for hardware, requiring high-performance filters, amplifiers and other components to process broadband signals, which not only greatly increases hardware costs, but also increases the difficulty of research and development. The complex hardware design makes it difficult to ensure the stability and reliability of the system, and it is prone to failures during actual use, affecting the accuracy and consistency of the measurement results. Therefore, in order to solve the above problems, the present application has developed a novel dual-port vector network analyzer. Summary of the invention

[0004] In order to make the signal range collected by the vector network analyzer smaller and reduce the bandwidth of the intermediate frequency signal, the present application provides a dual-port vector network analysis system.

[0005] A two-port vector network analysis system adopts the following technical solutions: A two-port vector network analysis system, connected to a device under test, comprises: The RF input module is used to perform power splitting 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 according to the second excitation signal; The local oscillator input module is used to perform power splitting 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 a local oscillator input signal according to the first local oscillator signal, the second local oscillator signal, and the first excitation signal; The vector network analysis module includes a receiver circuit. The receiver circuit is respectively connected to the output end of the local oscillator input module and the device under test. The receiver circuit is used to mix the RF signal generated by the device under test according to the excitation input signal with the local oscillator input signal to generate an intermediate frequency signal, and perform data analysis on the intermediate frequency signal to obtain the test data of the device under test.

[0006] By adopting the above technical solutions, through the power splitting of the excitation signal by the RF input module, and the local oscillator input module processes and synthesizes the first excitation signal and the local oscillator signal to synthesize the local oscillator input signal, vector network synthesis can be performed at a lower frequency to reach the required frequency, reducing the collected signal range, 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, realizing high-precision and high-resolution signal measurement, and significantly improving the measurement performance and reliability of the system.

[0007] Preferably, the local oscillator input module includes a local oscillator source circuit. The local oscillator source circuit includes an RF local oscillator source and a first power splitter. The input end of the first power splitter is connected to the output end of the RF local oscillator source to evenly split the local oscillator signal output by the RF local oscillator source into a first local oscillator signal and a second local oscillator signal; The local oscillator source circuit further includes a first frequency multiplier. The input end of the first frequency multiplier is connected to an output end of the first power splitter to perform frequency doubling processing on the second local oscillator signal and output it.

[0008] By adopting the above technical solutions, the local oscillator signal output by the RF local oscillator source in the local oscillator input module is evenly split into a first local oscillator signal and a second local oscillator signal by the first power splitter, realizing the precise distribution of the local oscillator signal. The second local oscillator signal is frequency doubled and output by the first frequency multiplier, effectively expanding the frequency range of the local oscillator signal, improving the flexibility and adaptability of the vector network analysis system, and being able to better meet the frequency requirements in different measurement scenarios.

[0009] Preferably, the local oscillator input module further includes a local oscillator frequency synthesis circuit, and the input end of the local oscillator frequency synthesis circuit is connected to the two output ends of the local oscillator source circuit and the output end of the first excitation signal; The local oscillator frequency synthesis circuit includes a first mixer, the input ends of the first mixer are respectively connected to the output end of the first local oscillator signal and the output end of the first excitation signal, and the first mixer mixes the first local oscillator signal and the first excitation signal to obtain a local oscillator synthesis signal; The local oscillator frequency synthesis circuit further includes a first RF switch, the first RF switch includes two input ports and one output port, and the output end of the first mixer and the output end of the second local oscillator signal are respectively connected to the two input ports of the first RF switch; The local oscillator frequency synthesis circuit further includes a second power divider, and the output port of the first RF switch is connected to the input end of the second power divider; The first RF switch is used to conduct the connection path between the local oscillator synthesis signal and the second power divider, or the connection path between the second local oscillator signal and the second power divider.

[0010] By adopting the above technical solution, the first mixer mixes the first local oscillator signal and the first excitation signal to obtain a local oscillator synthesis signal, which can synthesize a local oscillator signal with a specific frequency according to actual needs, so as to realize more precise processing and analysis of RF signals. The first RF switch provides flexibility in signal selection, and different local oscillator signal sources can be switched according to measurement requirements. The second power divider performs power division processing on the connected signals and then outputs them, meeting the requirements of a two-port network analyzer and satisfying the two-end test of the device under test, further improving the stability and reliability of signal processing.

[0011] Preferably, the local oscillator frequency synthesis circuit further includes a third power divider and a fourth power divider; One output end of the second power divider is connected to the input end of the third power divider, and the other output end of the second power divider is connected to the input end of the fourth power divider; The two output ends of the third power divider and the two output ends of the fourth power divider are both connected to the receiver circuit.

[0012] By adopting the above technical solution, the introduction of the third power divider and the fourth power divider can further refine the distribution path of the local oscillator signal, realizing multi-path precise distribution of the local oscillator signal. It not only improves the flexibility of signal distribution, but also enhances the stability of the system when processing complex signals, effectively reducing signal interference, and improving the measurement accuracy and reliability of the vector network analysis system.

[0013] Preferably, the RF input module includes an RF source circuit, which includes an RF signal source and a fifth power divider. The input end of the fifth power divider is connected to the output end of the RF signal source, and the fifth power divider evenly divides the excitation signal output by the RF signal source into a first excitation signal and a second excitation signal; The RF source circuit further includes a second frequency multiplier. One output end of the fifth power divider is connected to the input end of the second frequency multiplier to perform frequency doubling processing on the second excitation signal and output it; The other output end of the fifth power divider outputs the first excitation signal.

[0014] By adopting the above technical solution, the fifth power divider realizes the effective distribution of the excitation signal, ensuring the stability and uniformity of signal transmission. The second frequency multiplier performs frequency doubling processing on the second excitation signal and outputs it, improving the controllability of the signal frequency range and meeting the requirements in different measurement scenarios.

[0015] Preferably, the RF input module further includes an RF processing circuit, and the input end of the RF processing circuit is connected to the output end of the second excitation signal; The RF processing circuit includes a second RF switch, which includes an input port and two output ports. The two output ports of the second RF switch are respectively connected to the two test ports of the DUT through the receiver circuit. When the second RF switch is turned on between one of the test ports of the DUT, the second excitation signal is input into the DUT as an excitation input signal.

[0016] By adopting the above technical solution, the second RF switch can selectively conduct the second excitation signal to different test ports of the DUT according to actual needs, thereby realizing independent testing of different ports and improving the flexibility and efficiency of testing.

[0017] Preferably, the receiver circuit includes a first receiving port and a second receiving port. The first receiving port is connected to the first test port of the DUT, and the second receiving port is connected to the second test port of the DUT; The receiver circuit further includes a first directional coupler and a first mixing unit. The first directional coupler is respectively connected to the first receiving port and the input end of the first mixing unit; The first mixing unit includes a second mixer and a third mixer. The two input ends of the second mixer are respectively connected to the first output end of the first directional coupler and the first output end of the third power divider, and the two input ends of the third mixer are respectively connected to the second output end of the first directional coupler and the second output end of the third power divider; 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.

[0018] By adopting the above technical solution, two receiving ports are provided and respectively connected to two test ports of the device under test, so that the signal responses at both ends of the device under test can be obtained simultaneously, improving the test efficiency and data integrity. The first mixing unit mixes the two signals output by the first directional coupler and the local oscillator signal output by the third power divider respectively to generate intermediate frequency signals, effectively reducing the interference of high-frequency signals and improving the 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 of high-precision measurement.

[0019] 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; The output terminal of the second mixer is connected to the input terminal of the third radio frequency switch, the output terminal of the third mixer is connected to the input terminal of the fifth radio frequency switch, and the output terminals of the fourth radio frequency switch and the sixth radio frequency switch are respectively connected to the analog-to-digital converter; A third frequency multiplier is connected between the third radio frequency switch and the fourth radio frequency switch, and a fourth frequency multiplier is connected between the fifth radio frequency switch and the sixth radio frequency switch.

[0020] By adopting the above technical solution, the third radio frequency switch and the fourth radio frequency switch can selectively transmit the output signal of the second mixer to the analog-to-digital converter after being processed by the third frequency multiplier, so as to realize flexible regulation of the signal frequency, improve the precision and adaptability of signal processing; the fifth radio frequency switch and the sixth radio frequency switch can selectively transmit the output signal of the third mixer to the analog-to-digital converter after being processed by the fourth frequency multiplier, further enhancing the flexibility of signal processing, reducing unnecessary signal interference, and improving the measurement accuracy.

[0021] Preferably, the receiver circuit further includes a second directional coupler, a second mixing unit, and a second signal processing unit. The second directional coupler is respectively connected to the second receiving port and the input terminal of the second mixing unit; The second mixing unit includes a fourth mixer and a fifth mixer. Two input ends of the fourth mixer are respectively connected to a first output end of the second directional coupler and a first output end of the fourth power divider. Two input ends of the fifth mixer are respectively connected to a second output end of the second directional coupler and a second output end of the fourth power divider; Output ends of the fourth mixer and the fifth mixer are respectively connected to the second signal processing unit, and an output end of the second signal processing unit is connected to the analog-to-digital converter.

[0022] By adopting the above technical solution, the fourth mixer and the fifth mixer achieve precise mixing processing of the radio frequency signal and the local oscillator signal, thereby generating a stable intermediate frequency signal, and further improving the resolution of signal analysis; the second signal processing unit processes the intermediate frequency signals output by the fourth mixer and the fifth mixer and then transmits them to the analog-to-digital converter, ensuring the efficiency and accuracy of the signal conversion from the analog domain to the digital domain, and finally improving the measurement accuracy and stability of the entire system.

[0023] 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; The output end of the fourth mixer is connected to the input end of the seventh radio frequency switch, the output end of the fifth mixer is connected to the input end of the ninth radio frequency switch, and the output ends of the eighth radio frequency switch and the tenth radio frequency switch are respectively connected to the analog-to-digital converter; A fifth frequency multiplier is connected between the seventh radio frequency switch and the eighth radio frequency switch, and a sixth frequency multiplier is connected between the ninth radio frequency switch and the tenth radio frequency switch.

[0024] By adopting the above technical solution, the setting of the seventh radio frequency switch to the tenth radio frequency switch realizes flexible switching and processing of the signals output by the fourth mixer and the fifth mixer; the fifth frequency multiplier and the sixth frequency multiplier are respectively connected between the radio frequency switches, and can further perform frequency multiplication processing on the signals, thereby expanding the frequency range of the signals, improving the flexibility and adaptability of signal processing, enabling the system to better meet the signal requirements of different frequency components, and improving the measurement accuracy and reliability of the vector network analysis system.

[0025] In summary, the present application includes at least one of the following beneficial technical effects: 1. The present application can accurately generate the excitation input signal and the local oscillator input signal adapted to the device under test by performing power division processing on the excitation signal through the radio frequency input module and combining the local oscillator signal synthesis technology of the local oscillator input module, effectively reducing unnecessary wideband signal processing, and reducing system complexity and resource waste.

[0026] 2. By mixing the radio frequency signal and the local oscillator signal in the receiver circuit to generate an intermediate frequency signal, and then performing selective frequency doubling and data analysis, the present application avoids the noise and interference problems brought by the traditional wide intermediate frequency bandwidth design, and significantly improves the measurement accuracy and applicability.

[0027] 3. Through the modular design of the radio frequency input and local oscillator input structures, combined with flexible frequency doubling and mixing processing, the present application improves the adaptability and stability of the system, and reduces the hardware cost and R & D difficulty. Brief Description of the Drawings

[0028] Figure 1 is the schematic diagram of the radio frequency source circuit of this embodiment; Figure 2 is the schematic diagram of the radio frequency processing circuit of this embodiment; Figure 3 is the schematic diagram of the local oscillator source circuit of this embodiment; Figure 4 is the schematic diagram of the local oscillator frequency synthesis circuit of this embodiment; Figure 5 is the schematic diagram of the receiver circuit of this embodiment; Description of the Reference Numerals in the Drawings: 1. First power splitter; 2. First mixer; 3. First radio frequency switch; 4. Second power splitter; 5. Third power splitter; 6. Fourth power splitter; 7. Fifth power splitter; 8. Second radio frequency switch; 9. First directional coupler; 10. Second mixer; 11. Third mixer; 12. Third radio frequency switch; 13. Fourth radio frequency switch; 14. Fifth radio frequency switch; 15. Sixth radio frequency switch; 16. Third frequency doubler; 17. Fourth frequency doubler; 18. Second directional coupler; 19. Fourth mixer; 20. Fifth mixer; 21. Seventh radio frequency switch; 22. Eighth radio frequency switch; 23. Ninth radio frequency switch; 24. Tenth radio frequency switch; 25. Fifth frequency doubler; 26. Sixth frequency doubler; 27. First frequency doubler; 28. Second frequency doubler. Detailed Embodiments

[0029] To make the objectives, technical solutions, and advantages of the present application clearer, the following will further describe the embodiments of the present application in detail with reference to the drawings.

[0030] The embodiment of the present application provides a two-port vector network analysis system, which is connected to a device under test (DUT), and includes: a local oscillator input module, a radio frequency input module, and a vector network analysis module.

[0031] Among them, the radio frequency input module, such as Figure 1 and Figure 2As shown, it is used to split 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.

[0032] In an implementable specific manner, as Figure 1 shown, the RF input module includes an RF source circuit. The RF source circuit includes an RF signal source RF and a fifth power splitter 7. The input end of the fifth power splitter 7 is connected to the output end of the RF signal source. The fifth power splitter 7 evenly splits the excitation signal output by the RF signal source into a first excitation signal and a second excitation signal; The RF source circuit also includes a second frequency multiplier 28. One output end of the fifth power splitter 7 is connected to the input end of the second frequency multiplier 28 to perform frequency doubling processing on the second excitation signal, and obtain and output a signal with a frequency of 2 times RF marked as RF2.

[0033] The other output end of the fifth power splitter 7 outputs the first excitation signal.

[0034] In an implementable specific manner, as Figure 1 shown, an output matching network and an adjustable filtering network are sequentially connected between the RF signal source RF and the fifth power splitter 7. The output matching network is connected to the RF signal source and is used to achieve impedance matching between the RF signal source and the subsequent circuit. 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 filtering network is connected to the output matching network and can filter out the stray components and unwanted frequency components in the excitation signal, making the output excitation signal purer.

[0035] In an implementable specific manner, as Figure 1 shown, in the output branch of the second excitation signal, an RF signal amplifier and a filtering network are also connected. The second excitation signal first passes through the RF signal amplification circuit, the purpose of which is to increase the power amplitude of the second excitation signal to meet the requirements of subsequent processing or transmission; the signal after frequency doubling then passes through a filtering network to further filter out the stray signals and unwanted frequency components generated during the frequency doubling process, making the output second excitation signal with a frequency of RF2 purer.

[0036] In the output branch of the first excitation signal, an RF signal amplifier and a filtering network are also connected, and the function is the same as above, which will not be elaborated here.

[0037] In an implementable specific manner, as Figure 2 shown, the RF input module further includes an RF processing circuit, and the input end of the RF processing circuit is connected to the output end of the second excitation signal.

[0038] The radio frequency processing circuit includes a second radio frequency switch 8. The second radio frequency switch 8 includes an input port and two output ports, and the second radio frequency switch 8 is a single-pole double-throw switch; 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 conducts with one test port of the device under test, the second excitation signal is input into the device under test as the excitation input signal; As Figure 2 shown, when the second radio frequency switch 8 connects to the upper branch, the excitation input signal input into the device under test is RFP2. When the second radio frequency switch 8 connects to the lower branch, the excitation input signal input into the device under test is RFP1. These two excitation input signals will be input into two different test ports of the device under test to meet the test requirements of the dual-port.

[0039] In an implementable specific manner, as Figure 2 shown, in the radio frequency processing circuit, a filter network is also connected to the input end of the second radio frequency switch 8 for filtering the input second excitation signal RF2. By filtering out the stray frequency components, noise, and other unwanted signal components in the signal, the output signal is made purer.

[0040] In an implementable specific manner, as Figure 2 shown, a filter network and a radio frequency signal amplifier are connected to both output branches of the second radio frequency switch 8. After being selected by the second radio frequency switch 8, the second excitation signal first passes through a filter network to further filter and purify the signal, and then enters the radio frequency signal amplification module. The radio frequency signal amplification module will amplify the power of the signal to increase the intensity of the signal, and finally output the excitation input signal RFP1 or RFP2.

[0041] The local oscillator input module, as Figure 3 and Figure 4 shown, is used for power splitting the input local oscillator signal to obtain a first local oscillator signal and a second local oscillator signal, and is also used for synthesizing the local oscillator input signal based on the first local oscillator signal, the second local oscillator signal, and the first excitation signal.

[0042] In an implementable specific manner, as Figure 3 shown, the local oscillator input module includes a local oscillator source circuit. The local oscillator source circuit includes a radio frequency local oscillator LO and a first power splitter 1. The input end of the first power splitter 1 is connected to the output end of the radio frequency local oscillator to evenly power split the local oscillator signal output by the radio frequency local oscillator into a first local oscillator signal and a second local oscillator signal.

[0043] The local oscillator circuit further includes a first frequency multiplier 27. The input end of the first frequency multiplier 27 is connected to an output end of the first power divider 1, which multiplies the second local oscillator signal to obtain a signal with a frequency twice that of LO, marked as LO2, and outputs it.

[0044] In an implementable specific manner, as Figure 3 shown, an output matching network and an adjustable filtering network are sequentially connected between the radio frequency local oscillator source LO and the fifth power divider 7. The functions of the output matching network and the adjustable filtering network are the same as those in the above radio frequency source circuit, and will not be elaborated here.

[0045] In an implementable specific manner, as Figure 3 shown, in the output branch of the second local oscillator signal, a radio frequency signal amplifier and a filtering network are further connected; In the output branch of the first local oscillator signal, a radio frequency signal amplifier and a filtering network are similarly connected. Their functions are the same as those in the above radio frequency source circuit, and will not be elaborated here.

[0046] In an implementable specific manner, as Figure 4 shown, the local oscillator input module further includes a local oscillator frequency synthesis circuit. The input end of the local oscillator frequency synthesis circuit is connected to two output ends of the local oscillator circuit and the output end of the first excitation signal RF1.

[0047] Specifically, the local oscillator frequency synthesis circuit includes a first mixer 2. The input ends of the first mixer 2 are respectively connected to the output end of the first local oscillator signal LO1 and the output end of the first excitation signal RF1. The first mixer 2 mixes the first local oscillator signal and the first excitation signal to obtain a local oscillator synthesis signal.

[0048] In this embodiment, the first mixer 2 is an up-conversion mixer, and the frequency of the local oscillator synthesis 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.

[0049] The local oscillator frequency synthesis circuit further includes a first radio frequency switch 3. The first radio frequency switch 3 includes two input ports and one output port, and the first radio frequency switch 3 is a single-pole double-throw switch.

[0050] The output end of the first mixer 2 and the output end 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 ends of the first radio frequency switch 3 are respectively connected to the local oscillator synthesis signal and the second local oscillator signal LO2.

[0051] The local oscillator frequency synthesis circuit further includes a second power divider 4. The output port of the first radio frequency switch 3 is connected to the input end of the second power divider 4; The first radio frequency switch 3 is used to conduct the connection path between the local oscillator synthesis signal and the second power splitter 4, or the connection path between the second local oscillator signal and the second power splitter 4. With such a structure, the system can select the frequency of the local oscillator input signal.

[0052] In an implementable specific manner, as Figure 4 shown, the local oscillator frequency synthesis circuit further includes a third power splitter 5 and a fourth power splitter 6; One output terminal of the second power splitter 4 is connected to the input terminal of the third power splitter 5, and signals A1 and B1 are respectively output from both ends of the third power splitter 5; the other output terminal of the second power splitter 4 is connected to the input terminal of the fourth power splitter 6, and signals A2 and B2 are respectively output from both ends of the fourth power splitter 6.

[0053] Both output terminals of the third power splitter 5 and both output terminals of the fourth power splitter 6 are connected to the receiver circuit. A1 and B1 output by the third power splitter 5 and A2 and B2 output by the fourth power splitter 6 are respectively used as the local oscillator input signals of two different ports of the receiver.

[0054] In an implementable specific manner, as Figure 4 shown, an upper sideband filtering network is also connected in the local oscillator frequency synthesis circuit. The upper sideband filtering network is located between the first radio frequency switch 3 and the second power splitter 4, and filters the local oscillator signal selected by the first radio frequency switch 3. It is used to filter out unnecessary frequency components and only retain the upper sideband signal. In radio frequency communication, the upper sideband and the lower sideband are different frequency components generated after mixing. Selecting a specific sideband signal through filtering helps to improve the signal quality and reduce interference.

[0055] In an implementable specific manner, as Figure 4 shown, a filtering network and a radio frequency signal amplifier are sequentially connected between the second power splitter 4 and the third power splitter 5. A path of local oscillator signal split by the second power splitter 4 first passes through a filtering network to further filter out the spurious components in the signal, and then enters the radio frequency signal amplifier to amplify the power of the signal to meet the requirements of subsequent processing or transmission, and finally outputs the local oscillator input signals A1 and B1.

[0056] In an implementable specific manner, as Figure 4 shown, a filtering network and a radio frequency signal amplifier are sequentially connected between the second power splitter 4 and the fourth power splitter 6, and finally the local oscillator input signals A2 and B2 are output. The function is the same as above and will not be elaborated here.

[0057] The local oscillator input signals A1 and B1 and the local oscillator input signals A2 and B2 are respectively connected to both ends of the receiver circuit, and are respectively used as the local oscillator input signals of both ends for performing two-port vector network analysis A vector network analysis module, such as Figure 5 shown, includes a receiver circuit. The receiver circuit is respectively connected to the output end of the local oscillator input module and the device under test. The receiver circuit is used to mix the radio frequency signal generated by the device under test according to the excitation input signal with the local oscillator input signal to generate an intermediate frequency signal, and perform data analysis on the intermediate frequency signal to obtain the test data of the device under test.

[0058] In an implementable specific manner, the receiver circuit includes a first receiving port PORT1 and a second receiving port PORT2. The first receiving port is connected to the first test port of the device under test, and the second receiving port is connected to the second test port of the device under test.

[0059] In an implementable specific manner, on the side of the first receiving port of the receiver circuit: the receiver circuit includes a first directional coupler 9 and a first mixing unit. The first directional coupler 9 is respectively connected to the first receiving port and the input end of the first mixing unit.

[0060] The first mixing unit includes a second mixer 10 and a third mixer 11. Two input ends of the second mixer 10 are respectively connected to the first output end of the first directional coupler 9 and the first output end of the third power splitter 5. Two input ends of the third mixer 11 are respectively connected to the second output end of the first directional coupler 9 and the second output end of the third power splitter 5.

[0061] In this embodiment, the excitation input signal RFP1 is input into the device under test through the first test port of the device under test. After the excitation input signal acts on the device under test, reflected signals and transmission signals will be generated. These reflected signals and transmission signals are the radio frequency signals received by the receiver. Subsequently, the first mixing unit in the receiver circuit will mix the received radio frequency signal with the local oscillator signal to obtain the intermediate frequency signals IFA1 and IFB1.

[0062] For example, the excitation input signal is input into the device under test through PORT1 and the first test port. After the reflected signal of the device under test is separated by the first directional coupler 9, it enters the second mixer 10 and the third mixer 11 in the first mixing unit respectively to be mixed with the local oscillator signal to obtain the intermediate frequency signal.

[0063] The receiver circuit further includes a first signal processing unit, an analog-to-digital converter ADC, and a digital signal processor DSP. The output ends of the second mixer 10 and the third mixer 11 are respectively connected to the first signal processing unit. The output end 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.

[0064] In an implementable specific 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. Among them, the third RF switch 12 and the fifth RF switch 14 each include one input port and two output ports, and the fourth RF switch 13 and the sixth RF switch 15 each include two input ports and one output port; The output end of the second mixer 10 is connected to the input port of the third RF switch 12, and the output end of the third mixer 11 is connected to the input port of the fifth RF switch 14; The output ends of the fourth RF switch 13 and the sixth RF switch 15 are respectively connected to an analog-to-digital converter; A third frequency multiplier 16 is connected between the third RF switch 12 and the fourth RF switch 13. That is, among the two output branches of the third RF switch 12, one is connected to the third frequency multiplier 16, which can double the intermediate frequency signal IFA1.

[0065] A fourth frequency multiplier 17 is connected between the fifth RF switch 14 and the sixth RF switch 15. That is, among the two output branches of the fifth RF switch 14, one is connected to the fourth frequency multiplier 17, which can double the intermediate frequency signal IFB1.

[0066] In an implementable specific embodiment, low-pass filters LPF are respectively connected between the second mixer 10 and the third RF switch 12, and between the third mixer 11 and the fifth RF switch 14, for filtering out high-frequency stray signals and noises generated during the mixing process, and only allowing intermediate frequency signals below a specific frequency to pass through, thereby improving the purity of the signal.

[0067] In an implementable specific embodiment, for the second receiving port side of the receiver circuit, in order to ensure the accuracy of the phase, during the design process, a global symmetric design is carried out on the system architecture, that is, the second receiving port side is symmetrically designed with the first receiving port side.

[0068] 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 respectively connected to the second receiving port and the input end of the second mixing unit; The second mixing unit includes a fourth mixer 19 and a fifth mixer 20. The two input ends of the fourth mixer 19 are respectively connected to the first output end of the second directional coupler 18 and the first output end of the fourth power divider 6, and the two input ends of the fifth mixer 20 are respectively connected to the second output end of the second directional coupler 18 and the second output end of the fourth power divider 6.

[0069] In this embodiment, the excitation input signal RFP2 is input into the device under test (DUT) through the second test port of the DUT. After the excitation input signal acts on the DUT, reflected signals and transmitted signals will be generated, and these reflected signals and transmitted signals are the radio frequency signals received by the receiver. Subsequently, the second mixing unit in the receiver circuit will mix the received radio frequency signals with the local oscillator signal to obtain intermediate frequency signals IFA2 and IFB2.

[0070] For example, the excitation input signal is input into the DUT through PORT2 and the second test port. After the reflected signal of the DUT is separated by the second directional coupler 18, it enters the fourth mixer 19 and the fifth mixer 20 in the second mixing unit respectively to be mixed with the local oscillator signal, obtaining intermediate frequency signals.

[0071] 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.

[0072] In an implementable specific manner, 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, all of which are single-pole double-throw switches. Among them, both the seventh radio frequency switch 21 and the ninth radio frequency switch 23 include one input port and two output ports, and both the eighth radio frequency switch 22 and the tenth radio frequency switch 24 include two input ports and one output port; The output terminal of the fourth mixer 19 is connected to the input terminal of the seventh radio frequency switch 21, the output terminal of the fifth mixer 20 is connected to the input terminal of the ninth radio frequency switch 23, and the output terminals of the eighth radio frequency switch 22 and the tenth radio frequency switch 24 are respectively connected to the analog-to-digital converter.

[0073] A fifth frequency multiplier 25 is connected between the seventh radio frequency switch 21 and the eighth radio frequency switch 22, that is, among the two output branches of the seventh radio frequency switch 21, one is connected with the fifth frequency multiplier 25, which can double the intermediate frequency signal IFA2.

[0074] A sixth frequency multiplier 26 is connected between the ninth radio frequency switch 23 and the tenth radio frequency switch 24, that is, among the two output branches of the ninth radio frequency switch 23, one is connected with the sixth frequency multiplier 26, which can double the intermediate frequency signal IFB2.

[0075] In an implementable specific manner, low-pass filters LPF are respectively connected between the fourth mixer 19 and the seventh radio frequency switch 21, and between the fifth mixer 20 and the ninth radio frequency switch 23, which are used to filter out high-frequency stray signals and noise generated during the mixing process, and only allow intermediate frequency signals below a specific frequency to pass through, thereby improving the purity of the signals.

[0076] In another feasible embodiment, such as Figure 1 and Figure 3 , assuming that a radio frequency signal source circuit is developed to generate a radio frequency signal source in the range of 50 MHz to 4 GHz, that is, the range of RF1 is 50 MHz to 4 GHz, RF2 is equal to 2 * RF1, and the range of RF2 is 100 MHz to 8 GHz. The range of LO1 is 50 MHz to 4 GHz, LO2 is equal to 2 * LO1, and the range of LO2 is 100 MHz to 8 GHz.

[0077] Such as Figure 2 , after filtering and power splitting the RF2 link, the output signal is sent to the Figure 5 link to form a radio frequency signal source in the range of 100 MHz to 8 GHz.

[0078] Such as Figure 4 , perform a key signal mixing operation. After mixing RF1 and LO1, signals in the upper and lower frequency bands are formed. Filter out the signals in the lower frequency band and extract the signals in the upper frequency band (RF1 + LO1). Here, perform switching control with the signals of LO2. Within 100 MHz to 8 GHz, it is divided into two frequency bands. When the frequency is lower than 4 GHz, the first radio frequency switch 3 switches to the link of the local oscillator synthesis signal; when the frequency is higher than 4 GHz, the first radio frequency switch 3 switches to the link of the second local oscillator signal LO2.

[0079] The local oscillator input signal passes through a filter network and power splitting and then enters the receiver circuit of this system to participate in mixing.

[0080] In the receiver link of the vector network analyzer, it is necessary to ensure the phase and amplitude symmetry of the link. Such as Figure 5 , the radio frequency signal source passes through a directional coupler, and coupled and reflected signals can be obtained. The receiver circuit mixes with the signals of the directional coupler under the same phase and amplitude conditions to obtain 10 MHz intermediate frequency signals of A1, B1, A2, and B2.

[0081] Use an analog-to-digital converter to collect these 4 groups of signals and send them to an FPGA or DSP for data analysis and Fourier transform.

[0082] The specific calculation is as follows: When the frequency is lower than 4 GHz, 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 higher than 4 GHz, 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 doubling the frequency in the frequency band below 4 GHz, the same IF signal can be maintained.

[0083] Through the above technical solution, an 8 GHz two-port vector network analyzer is designed. Compared with the traditional 8 GHz two-port network analyzer, the test data are consistent. At the same time, the on-board radio frequency signal source reaches 4 GHz, and the R & D difficulty of a single board is greatly reduced. And because the intermediate-frequency bandwidth becomes narrower, the power of the noise and interference signals entering the system is correspondingly reduced, improving the signal-to-noise ratio of the signal, as well as the measurement accuracy and stability.

[0084] The above are all the preferred embodiments of this application. It does not limit the protection scope of this application accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of this application should be covered within the protection scope of this application.

Claims

1. A dual-port vector network analysis system, connected to a device under test, characterized in that, Comprising: A radio frequency input module, configured to perform power splitting on an input excitation signal to obtain a first excitation signal and a second excitation signal, and further configured to determine an excitation input signal of the device under test according to the second excitation signal; A local oscillator input module, configured to perform power splitting on an input local oscillator signal to obtain a first local oscillator signal and a second local oscillator signal, and further configured to synthesize a local oscillator input signal according to the first local oscillator signal, the second local oscillator signal, and the first excitation signal; A vector network analysis module, including a receiver circuit, wherein the receiver circuit is respectively connected to an output end of the local oscillator input module and the device under test, and the receiver circuit is configured to mix a radio frequency signal generated by the device under test according to the excitation input signal with the local oscillator input signal to generate an intermediate frequency signal, and perform data analysis on the intermediate frequency signal to obtain test data of the device under test.

2. The two-port vector network analysis system according to claim 1, wherein: The local oscillator input module includes a local oscillator source circuit, and the local oscillator source circuit includes a radio frequency local oscillator source and a first power splitter (1), an input end of the first power splitter (1) is connected to an output end of the radio frequency local oscillator source, and the local oscillator signal output by the radio frequency local oscillator source is evenly power split into a first local oscillator signal and a second local oscillator signal; The local oscillator source circuit further includes a first frequency multiplier (27), an input end of the first frequency multiplier (27) is connected to an output end of the first power splitter (1), and the second local oscillator signal is frequency multiplied and output.

3. The two-port vector network analysis system according to claim 2, wherein: The local oscillator input module further includes a local oscillator frequency synthesis circuit, and an input end of the local oscillator frequency synthesis circuit is connected to two output ends of the local oscillator source circuit and an output end of the first excitation signal; The local oscillator frequency synthesis circuit includes a first mixer (2), input ends of the first mixer (2) are respectively connected to an output end of the first local oscillator signal and an output end of the first excitation signal, and the first mixer (2) mixes the first local oscillator signal and the first excitation signal to obtain a local oscillator synthesis signal; The local oscillator frequency synthesis circuit further includes a first radio frequency switch (3), the first radio frequency switch (3) includes two input ports and one output port, and an output end of the first mixer (2) and an output end of the second local oscillator signal are respectively connected to the two input ports of the first radio frequency switch (3); The local oscillator frequency synthesis circuit further includes a second power splitter (4), and an output port of the first radio frequency switch (3) is connected to an input end of the second power splitter (4); The first radio frequency switch (3) is configured to conduct a connection path between the local oscillator synthesis signal and the second power splitter (4), or a connection path between the second local oscillator signal and the second power splitter (4).

4. The dual-port vector network analysis system according to claim 3, wherein: The local oscillator frequency synthesis circuit further includes a third power splitter (5) and a fourth power splitter (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 of the two output terminals of the third power divider (5) and the two output terminals of the fourth power divider (6) are connected to the receiver circuit.

5. The two-port vector network analysis system according to claim 1, wherein: The RF input module includes an RF source circuit, and the RF source circuit includes an RF 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 RF signal source, and the fifth power divider (7) equally divides the excitation signal output by the RF signal source into a first excitation signal and a second excitation signal; The RF source circuit further 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 doubling processing on the second excitation signal and output it; The other output terminal of the fifth power divider (7) outputs the first excitation signal.

6. The two-port vector network analysis system according to claim 5, wherein: The RF input module further includes an RF processing circuit, and the input terminal of the RF processing circuit is connected to the output terminal of the second excitation signal; The RF processing circuit includes a second RF switch (8). The second RF switch (8) includes an input port and two output ports. The two output ports of the second RF switch (8) are respectively connected to the two test ports of the device under test through the receiver circuit. When the second RF switch (8) is conductive with one of the test ports of the device under test, the second excitation signal is input into the device under test as an excitation input signal.

7. The dual-port vector network analysis system according to claim 4, wherein: The receiver circuit includes a first receiving port and a second receiving port. The first receiving port is connected to the first test port of the device under test, and the second receiving port is connected to the second test port of the device under test; The receiver circuit further includes a first directional coupler (9) and a first mixing unit. The first directional coupler (9) is respectively connected to the first receiving port and the input terminal of the first mixing unit; 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), and 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 terminals of the second mixer (10) and the third mixer (11) 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.

8. The dual-port vector network analysis system according to claim 7, wherein: 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); The output terminal of the second mixer (10) is connected to the input terminal of the third RF switch (12). The output terminal of the third mixer (11) is connected to the input terminal of the fifth RF switch (14). The output terminals 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).

9. The dual-port vector network analysis system according to claim 7, wherein: 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 respectively connected to the second receiving port and the input terminal of the second mixing unit; 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.

10. The dual-port vector network analysis system according to claim 9, wherein: 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); The output terminal of the fourth mixer (19) is connected to the input terminal of the seventh RF switch (21). The output terminal of the fifth mixer (20) is connected to the input terminal of the ninth RF switch (23). The output terminals of the eighth RF switch (22) and the tenth RF 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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