Low-cost two-port vector network analysis device

Abstract

The utility model discloses a low-cost two-port vector network analysis device which comprises a first test port, a second test port, a directional bridge module, a switch control module, a radio frequency signal source, a digital attenuator, a local oscillator signal source, a frequency mixer, an intermediate frequency processing circuit and an ADC. Wherein the output end of the radio frequency signal source is coupled with the input end of the digital attenuator, and the output end of the digital attenuator is coupled with the switch control module; the first test port and the second test port are respectively connected with two ends of a tested piece, and the first test port and the second test port are connected with the directional bridge module through the switch control module; the output end of the local oscillator signal source is connected with the frequency mixer, and the output end of the frequency mixer is coupled to the ADC through the intermediate frequency processing circuit. According to the utility model, only one frequency mixer is adopted to calculate four parameters of a test parameter S.

Description

Technical Field

[0001] The utility model relates to the technical field of vector network analyzers, in particular to a low-cost two-port vector network analysis device. Background Art

[0002] Vector network analyzer is a common microwave radio frequency measuring instrument. It can be used for high-frequency passive devices and components. It is mainly used to test the performance parameters amplitude and phase of high-frequency devices and circuit systems. Vector network analyzer can test the reflection parameters of single-port devices and measure the transmission parameters of dual-port devices.

[0003] Traditional vector network analyzers mainly include RF and local oscillator signal sources, signal source filter circuits, channel selection switches, digitally controlled attenuators, directional bridges, mixers, operational amplifiers, etc. Traditional two-port vector network analyzers require at least three mixers to collect the reference signal R, the reflected signal A, and the transmitted signal B respectively; the existing two-port single-mixer vector network analyzer solution can only output power from one port, and the other port can only be used as a port for receiving power, so it can only test S11 (A1 / R) parameters and S21 (B1 / R) parameters, but cannot test S22 (A2 / R) and S12 (B2 / R) parameters.

[0004] Existing technologies can no longer meet people’s needs at this stage. Based on the current situation, it is urgent to reform existing technologies. Utility Model Content

[0005] The purpose of the utility model is to provide a low-cost two-port vector network analysis device to solve the problems raised in the above background technology.

[0006] The utility model provides the following technical solution: a low-cost two-port vector network analysis device, comprising: a first test port, a second test port, a directional bridge module, a switch control module, a radio frequency signal source, a digital attenuator, a local oscillator signal source, a mixer, an intermediate frequency processing circuit and an ADC; wherein:

[0007] The output end of the RF signal source is coupled to the input end of the digital attenuator, wherein the RF signal source is used to generate a RF signal, and the digital attenuator is used to perform power control on the RF signal;

[0008] The output end of the digital attenuator is coupled to a switch control module, and the switch control module includes: a first control switch, a second control switch, a third control switch and a fourth control switch;

[0009] The directional bridge module comprises: a first directional bridge and a second directional bridge, and each directional bridge has a through end and a coupling end; the directional bridge module is used to separate the radio frequency signal so that the radio frequency signal is transmitted in a directional manner;

[0010] The first test port and the second test port are connected to two ends of the device under test respectively, and the first test port and the second test port are connected to the through ends of the first directional bridge and the second directional bridge respectively through the first control switch and the second control switch;

[0011] The output end of the digital attenuator is coupled to the input end of the fourth control switch, and the fourth control switch adjusts the internal channel to the third channel connected to the second channel of the third control switch, and the fourth control switch adjusts the internal channel to the first channel coupled to the input end of the first bridge, and the fourth control switch adjusts the internal channel to the fourth channel coupled to the input end of the second bridge;

[0012] The third control switch adjusts the internal channel to connect the first channel to the coupling end of the second bridge, and the third control switch adjusts the internal channel to connect the fourth channel to the coupling end of the first bridge, and the output end of the third control switch is coupled to the mixer;

[0013] The output end of the local oscillator signal source is connected to the mixer, and the output end of the mixer is coupled to the ADC through the intermediate frequency processing circuit. The mixer mixes the RF signal generated by the RF signal source with the local oscillator signal generated by the local oscillator signal source to generate an intermediate frequency signal, which reaches the ADC through the intermediate frequency processing circuit.

[0014] Preferably, when testing the reference signal R, the fourth control switch adjusts the internal channel to the third channel, and the third control switch adjusts the internal channel to the second channel.

[0015] Preferably, when testing the reflected signal A2 of the second test port, the fourth control switch adjusts the internal channel to the fourth channel, the second control switch adjusts the internal channel to the second channel, and the third control switch adjusts the internal channel to the first channel.

[0016] Preferably, when testing the transmission signal B2 from the second test port to the first test port, the fourth control switch adjusts the internal channel to the fourth channel, the second control switch adjusts the internal channel to the second channel, the first control switch adjusts the internal channel to the second channel, and the third control switch adjusts the internal channel to the fourth channel.

[0017] The utility model has the following beneficial effects

[0018] By adjusting the signal flow direction of the internal channel through the switch control module, the number of mixers can be reduced without affecting the test, which can significantly reduce the vector network cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the circuit structure of the utility model;

[0020] Figure 2 This is a schematic diagram of the structure of the test reference signal R of the utility model;

[0021] Figure 3 This is a schematic diagram of the circuit structure of the working process of the utility model for testing the reflected signal A1 circuit;

[0022] Figure 4 This is a schematic diagram of the circuit structure of the working process of the utility model testing the reflected signal A2 circuit;

[0023] Figure 5 This is a schematic diagram of the circuit structure of the working process of the utility model for testing the transmission signal B1 from the first test port to the second test port;

[0024] Figure 6 This is a circuit structure diagram of the working process of the utility model for testing the transmission signal B1 from the second test port to the first test port. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. All other embodiments obtained by ordinary technicians in the field of the utility model without creative work are within the scope of protection of the utility model.

[0026] refer to Figure 1 The utility model provides the following technical solution: a low-cost two-port vector network analysis device, including: a first test port, a second test port, a directional bridge module, a switch control module, a radio frequency signal source, a digital attenuator, a local oscillator signal source, a mixer, an intermediate frequency processing circuit, and an ADC; wherein,

[0027] The output end of the radio frequency signal source is coupled to the input end of the digital attenuator. The radio frequency signal source is used to generate a required radio frequency signal, and the digital attenuator is used to perform power control on the radio frequency signal.

[0028] The output end of the digital attenuator is coupled to a switch control module, which includes: a first control switch, a second control switch, a third control switch and a fourth control switch; each control switch in the switch control module adopts a single-pole four-throw switch to realize switching control between channels inside the control switch;

[0029] The directional bridge module comprises: a first directional bridge and a second directional bridge, and each directional bridge has a through end and a coupling end; the directional bridge module separates the radio frequency signal to achieve directional transmission of the radio frequency signal.

[0030] The first test port and the second test port are connected to two ends of the device under test respectively, and the first test port and the second test port are connected to the through ends of the first directional bridge and the second directional bridge respectively through the first control switch and the second control switch;

[0031] The output end of the digital attenuator is coupled to the input end of the fourth control switch, and the fourth control switch adjusts the internal channel to the third channel connected to the second channel of the third control switch, and the fourth control switch adjusts the internal channel to the first channel coupled to the input end of the first bridge, and the fourth control switch adjusts the internal channel to the fourth channel coupled to the input end of the second bridge;

[0032] The third control switch adjusts the internal channel to connect the first channel to the coupling end of the second bridge, and the third control switch adjusts the internal channel to connect the fourth channel to the coupling end of the first bridge, and the output end of the third control switch is coupled to the mixer;

[0033] The first control switch adjusts the internal channel to couple the second channel with the first test port, and the first control switch is connected to the first directional bridge via a straight-through connection line. The straight-through connection line has no directionality and can be used as both a signal input and a signal output. In this embodiment, the radio frequency signal is transmitted to the first test port via the straight-through connection line as a signal input, and the reflected signal at the first test port can also be transmitted to the first directional bridge via the straight-through connection line as a signal output; the second control switch adjusts the internal channel to couple the second channel with the second test port, and the second control switch is connected to the second directional bridge via the straight-through connection line. The working principle of the specific embodiment is the same as the above principle;

[0034] A fourth channel in the internal channels of the first control switch and the second control switch is fixedly grounded;

[0035] The output end of the local oscillator signal source is connected to the mixer, and the output end of the mixer is coupled to the ADC through the intermediate frequency processing circuit; the local oscillator signal source generates a local oscillator signal and mixes it with the radio frequency signal, and outputs the intermediate frequency signal to the intermediate frequency processing circuit through the mixer. The intermediate frequency processing circuit amplifies and filters the intermediate frequency signal and outputs a pure intermediate frequency signal to the ADC. The ADC digitizes the intermediate frequency signal and converts the analog signal into a digital signal.

[0036] refer to Figure 2As an embodiment of the utility model, the process of testing the reference signal R is as follows: the RF signal source generates a RF signal, which enters the fourth control switch after power adjustment by the digital attenuator, the fourth control switch adjusts the internal channel to the third channel, and the third control switch adjusts the internal channel to the second channel, so that the RF signal can reach the mixer after coming out of the RF signal source, and the RF signal and the local oscillator signal generated from the local oscillator signal source are mixed by the mixer to generate an intermediate frequency signal, which reaches the ADC through the intermediate frequency processing circuit;

[0037] refer to Figure 3 As an embodiment of the utility model, the process of testing the reflected signal A1 of the first test port is as follows: the fourth control switch adjusts the internal channel to the first channel, the first control switch adjusts the internal channel to the second channel, and the third control switch adjusts the internal channel to the fourth channel. After the RF signal comes out from the RF signal source, it first reaches the first directional bridge through the fourth control switch, and the RF signal reaches the first test port through the through end of the first directional bridge. At this time, the RF signal is separated into the reflected signal A1 and the transmitted signal B1, wherein the reflected signal A1 is reflected at the first test port, coupled through the coupling end of the first directional bridge, and then reaches the mixer through the third control switch, and is mixed with the local oscillator signal generated from the local oscillator signal source to generate an intermediate frequency signal, which reaches the ADC through the intermediate frequency processing circuit;

[0038] refer to Figure 4 As an embodiment of the utility model, the process of testing the reflected signal A2 of the second test port is as follows: the fourth control switch adjusts the internal channel to the fourth channel, the second control switch adjusts the internal channel to the second channel, and the third control switch adjusts the internal channel to the first channel. After the RF signal comes out from the RF signal source, it first passes through the fourth control switch to reach the second directional bridge, and the RF signal passes through the through end of the second directional bridge to reach the second test port. At this time, the RF signal is separated into the reflected signal A2 and the transmitted signal B2, wherein the reflected signal A2 is reflected at the second test port, coupled through the coupling end of the second directional bridge, and then reaches the mixer through the third control switch, and is mixed with the local oscillator signal generated from the local oscillator signal source to generate an intermediate frequency signal, which reaches the ADC through the intermediate frequency processing circuit;

[0039] refer to Figure 5As an embodiment of the utility model, the process of testing the transmission signal B1 from the first test port to the second test port is as follows: the fourth control switch adjusts the internal channel to the first channel, the first control switch adjusts the internal channel to the second channel, the second control switch adjusts the internal channel to the second channel, and the third control switch adjusts the internal channel to the first channel. After the RF signal comes out from the RF signal source, it first passes through the fourth control switch to reach the first directional bridge, and the RF signal passes through the through end of the first directional bridge to reach the first test port. At this time, the RF signal is separated into a reflection signal A1 and a transmission signal B1, wherein the transmission signal B1 passes from the first test port through the device under test to the second test port, and the transmission signal B1 passes through the second control switch to reach the second directional bridge, and passes through the coupling end of the second directional bridge through the third control switch to reach the mixer, and is mixed with the local oscillator signal generated from the local oscillator signal source to generate an intermediate frequency signal, and reaches the ADC through the intermediate frequency processing circuit;

[0040] refer to Figure 6 As an embodiment of the utility model, the process of testing the transmission signal B2 from the second test port to the first test port is: the fourth control switch adjusts the internal channel to the fourth channel, the second control switch adjusts the internal channel to the second channel, the first control switch adjusts the internal channel to the second channel, and the third control switch adjusts the internal channel to the fourth channel. After the RF signal comes out from the RF signal source, it first passes through the fourth control switch to reach the second directional bridge, and the RF signal reaches the second test port through the straight-through end of the second directional bridge. At this time, the RF signal is separated into a reflected signal A2 and a transmission signal B2, wherein the transmission signal B2 reaches the first test port from the second test port through the device under test, and the transmission signal B2 reaches the first directional bridge through the first control switch, and reaches the mixer through the coupling end of the first directional bridge through the third control switch, and is mixed with the local oscillator signal generated from the local oscillator signal source to generate an intermediate frequency signal, and reaches the ADC through the intermediate frequency processing circuit.

[0041] In this embodiment, the test parameter S of the dual port is calculated as follows: S11 = A1 / R, S22 = A2 / R, S21 = B1 / R, S12 = B2 / R. It can be seen that the technical solution of the utility model can calculate the four parameters of the test parameter S, effectively solving the problems in the background technology.

[0042] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A low-cost two-port vector network analysis device, characterized in that: include: A first test port, a second test port, a directional bridge module, a switch control module, a radio frequency signal source, a digital attenuator, a local oscillator signal source, a mixer, an intermediate frequency processing circuit and an ADC; wherein, The output end of the RF signal source is coupled to the input end of the digital attenuator, wherein the RF signal source is used to generate a RF signal, and the digital attenuator is used to perform power control on the RF signal; The output end of the digital attenuator is coupled to a switch control module, and the switch control module includes: a first control switch, a second control switch, a third control switch and a fourth control switch; The directional bridge module comprises: a first directional bridge and a second directional bridge, and each directional bridge has a through end and a coupling end; the directional bridge module is used to separate the radio frequency signal so that the radio frequency signal is transmitted in a directional manner; The first test port and the second test port are connected to two ends of the device under test respectively, and the first test port and the second test port are connected to the through ends of the first directional bridge and the second directional bridge respectively through the first control switch and the second control switch; The output end of the digital attenuator is coupled to the input end of the fourth control switch, and the fourth control switch adjusts the internal channel to the third channel connected to the second channel of the third control switch, and the fourth control switch adjusts the internal channel to the first channel coupled to the input end of the first bridge, and the fourth control switch adjusts the internal channel to the fourth channel coupled to the input end of the second bridge; The third control switch adjusts the internal channel to connect the first channel to the coupling end of the second bridge, and the third control switch adjusts the internal channel to connect the fourth channel to the coupling end of the first bridge, and the output end of the third control switch is coupled to the mixer; The output end of the local oscillator signal source is connected to the mixer, and the output end of the mixer is coupled to the ADC through the intermediate frequency processing circuit. The mixer mixes the RF signal generated by the RF signal source with the local oscillator signal generated by the local oscillator signal source to generate an intermediate frequency signal, which reaches the ADC through the intermediate frequency processing circuit.

2. A low-cost two-port vector network analysis device according to claim 1, characterized in that: Each control switch in the switch control module adopts a single-pole four-throw switch to achieve switching control between channels inside the control switch.

3. A low-cost two-port vector network analysis device according to claim 1, characterized in that: A fourth channel among the inner channels of the first control switch and the second control switch is fixedly grounded.

4. A low-cost two-port vector network analysis device according to claim 1, characterized in that: The first control switch adjusts the internal channel to couple the second channel to the first test port, and the first control switch is connected to the first directional bridge via a straight-through connection line; the second control switch adjusts the internal channel to couple the second channel to the second test port, and the second control switch is connected to the second directional bridge via a straight-through connection line.

5. A low-cost two-port vector network analysis device according to claim 4, characterized in that: The straight-through connection line has no directionality and can be used as a signal input to transmit radio frequency signals to the first test port and the second test port, and can also be used as a signal output at the first test port and the second test port to transmit reflected signals to the first directional bridge and the second directional bridge.

6. A low-cost two-port vector network analysis device according to claim 1, characterized in that: When testing the reference signal R, the fourth control switch adjusts the internal channel to the third channel, and the third control switch adjusts the internal channel to the second channel, so that the RF signal can reach the mixer after coming out of the RF signal source, and the RF signal and the local oscillator signal generated from the local oscillator signal source are mixed in the mixer to generate an intermediate frequency signal, which reaches the ADC through the intermediate frequency processing circuit.

7. A low-cost two-port vector network analysis device according to claim 1, characterized in that: When testing the reflected signal A1 of the first test port, the fourth control switch adjusts the internal channel to the first channel, the first control switch adjusts the internal channel to the second channel, and the third control switch adjusts the internal channel to the fourth channel; After the RF signal comes out from the RF signal source, it first reaches the first directional bridge through the fourth control switch, and then reaches the first test port through the through end of the first directional bridge. At this time, the RF signal is separated into a reflected signal A1 and a transmitted signal B1, wherein the reflected signal A1 is reflected at the first test port, coupled through the coupling end of the first directional bridge, and then reaches the mixer through the third control switch, and is mixed with the local oscillator signal generated from the local oscillator signal source to generate an intermediate frequency signal, which reaches the ADC through the intermediate frequency processing circuit.

8. A low-cost two-port vector network analysis device according to claim 1, characterized in that: When testing the reflected signal A2 of the second test port, the fourth control switch adjusts the internal channel to the fourth channel, the second control switch adjusts the internal channel to the second channel, and the third control switch adjusts the internal channel to the first channel; After the RF signal comes out from the RF signal source, it first reaches the second directional bridge through the fourth control switch, and then reaches the second test port through the through end of the second directional bridge. At this time, the RF signal is separated into a reflected signal A2 and a transmitted signal B2, wherein the reflected signal A2 is reflected at the second test port, coupled through the coupling end of the second directional bridge, and then reaches the mixer through the third control switch, and is mixed with the local oscillator signal generated from the local oscillator signal source to generate an intermediate frequency signal, which reaches the ADC through the intermediate frequency processing circuit.

9. A low-cost two-port vector network analysis device according to claim 1, characterized in that: When testing the transmission signal B1 from the first test port to the second test port, the fourth control switch adjusts the internal channel to the first channel, the first control switch adjusts the internal channel to the second channel, the second control switch adjusts the internal channel to the second channel, and the third control switch adjusts the internal channel to the first channel; After the RF signal comes out from the RF signal source, it first reaches the first directional bridge through the fourth control switch, and then reaches the first test port through the through end of the first directional bridge. At this time, the RF signal is separated into a reflected signal A1 and a transmission signal B1, wherein the transmission signal B1 reaches the second test port from the first test port through the device under test, and the transmission signal B1 reaches the second directional bridge through the second control switch, and reaches the mixer through the coupling end of the second directional bridge through the third control switch, and is mixed with the local oscillator signal generated from the local oscillator signal source to generate an intermediate frequency signal, which reaches the ADC through the intermediate frequency processing circuit.

10. A low-cost two-port vector network analysis device according to claim 1, characterized in that: When testing the transmission signal B2 from the second test port to the first test port, the fourth control switch adjusts the internal channel to the fourth channel, the second control switch adjusts the internal channel to the second channel, the first control switch adjusts the internal channel to the second channel, and the third control switch adjusts the internal channel to the fourth channel; After the RF signal comes out from the RF signal source, it first reaches the second directional bridge through the fourth control switch, and then reaches the second test port through the through end of the second directional bridge. At this time, the RF signal is separated into a reflected signal A2 and a transmission signal B2, wherein the transmission signal B2 reaches the first test port from the second test port through the device under test, and the transmission signal B2 reaches the first directional bridge through the first control switch, and reaches the mixer through the coupling end of the first directional bridge through the third control switch, and is mixed with the local oscillator signal generated from the local oscillator signal source to generate an intermediate frequency signal, which reaches the ADC through the intermediate frequency processing circuit.

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