High system directivity signal distribution circuit suitable for multi-port vector network analyzer

Abstract

The utility model provides a high system directivity signal distribution circuit suitable for a multi-port vector network analyzer. External test ports are matched with independent single bi-directional couplers. Compared with the prior art, no additional matrix radio frequency switch is arranged between the coupler and the to-be-tested piece, the directivity of the system is greatly improved due to the reduction of insertion loss, the upper limit of working frequency is improved, and the stability and performance indexes of the whole test system are also remarkably improved. Meanwhile, an isolation end, which is terminated with a matched load, in the single directional coupler is defined as an additional coupling port to form the dual directional coupler, so that the single dual directional coupler can meet the functional requirements of two single directional couplers of a signal distribution circuit in a traditional vector network analyzer, and the cost and the size can be reduced to a certain extent. In addition, the receiver amplification matrix can keep the signal-to-noise ratio of the receiver relatively stable, and also can improve the system dynamic range of the whole multi-port vector network analyzer.

Description

Technical Field

[0001] The utility model belongs to the technical field of electronic measuring instruments, is applied to a working circuit of a vector network analyzer, and specifically relates to a high system directivity signal distribution circuit suitable for a multi-port vector network analyzer. Background Art

[0002] Vector network analyzer is one of the most commonly used instruments in the field of radio frequency microwave and scientific research and production activities. It is mainly used to measure the reflection characteristics and transmission characteristics of devices and networks. At present, most of the vector network analyzers used are dual-port, which is mainly due to economic considerations and usage scenarios. The price of dual-port vector network analyzers is relatively cheap and the devices or networks to be tested in most scenarios are dual-port. In recent years, with the continuous improvement of the performance indicators of complete equipment, various multi-port components and multi-functional modules have appeared one after another, such as power synthesis networks, multi-channel feeding networks, and array antennas integrated with multiple T / R components, which also makes multi-channel beamforming and multi-channel coherent reception an important feature of modern electronic technology. At the same time, multi-port devices or networks need to perform accurate and rapid testing and analysis of their scattering parameter characteristics in various links such as research and development, production, installation and commissioning, and maintenance. Only multi-port vector network analyzers can well meet the requirements for comprehensive, rapid and accurate testing of a large number of multi-port devices or networks.

[0003] Traditional multi-port vector network analyzer signal distribution circuits such as Figure 2 As shown, it includes a first reference coupler C12, a second reference coupler C11, a first measurement coupler C22, a second measurement coupler C21, a local oscillator source S2, an excitation source S1, etc. Test port A and test port B are both connected to an external switch test device, and the switch test device only contains a matrix RF switch to provide the required test path. The significant advantages of the traditional multi-port vector network analyzer signal distribution circuit are: simple circuit structure and control logic, and low cost. The simple circuit structure and control logic mainly refer to the realization of multi-ports only by connecting the switch test device to the test port of the vector network analyzer, and the switch test device can be customized according to specific needs. The ports after expansion can be partially fully crossed, and the other ports are simple switch trees. Low cost means that each test port after expansion does not have an independent matching coupler, but reuses the corresponding matching couplers respectively, and the switch test device only has a matrix RF switch provided to the excitation source.

[0004] Although the traditional multi-port vector network analyzer signal distribution circuit has the above significant advantages, it also has a major defect that cannot be ignored: the upper limit of the operating frequency is low and the system directivity is greatly reduced. Because the switch test device is located after the matching coupler, as the operating frequency increases, the insertion loss caused by the matrix RF switch becomes larger, which directly affects the output power of the test port after expansion on the one hand, and deteriorates the system directivity by twice the insertion loss on the other hand, which directly leads to a significant reduction in the stability and performance indicators of the entire test system. Utility Model Content

[0005] The purpose of the utility model is to address the problems existing in the technical background and propose a high system directivity signal distribution circuit suitable for a multi-port vector network analyzer, which can greatly improve the system directivity and increase its upper limit of operating frequency.

[0006] The purpose of the utility model is achieved through the following technical solutions:

[0007] The utility model provides a high system directivity signal distribution circuit suitable for a multi-port vector network analyzer, comprising:

[0008] Motivational source;

[0009] Local oscillator source;

[0010] A dual directional coupler group, wherein the dual directional coupler group comprises at least two dual directional couplers and the through input end of each dual directional coupler is respectively connected to the excitation source through an excitation source switch matrix;

[0011] A reference receiver branch, wherein the reference receiver branch has at least two branches, and each reference receiver branch is used to mix the output signal of the reference coupling end of the dual directional coupler with the local oscillator source and then send the mixed signal to the reference receiver;

[0012] A test receiver branch, wherein the test receiver branch has at least two branches, and each test receiver branch is used to respectively measure the output signal of the coupling end of the dual directional coupler and the local oscillator source and then send the mixed signal to the measurement receiver;

[0013] A test port is connected to the through output end of the dual directional coupler.

[0014] The utility model has the following advantages:

[0015] 1) This solution is equipped with an independent single dual directional coupler at the external test port. The dual directional coupler can directly obtain the reference signal and the measurement signal reflected or transmitted by the DUT. There is no additional matrix RF switch between the coupler and the DUT. The reduction in insertion loss greatly improves the system directivity, increases the upper limit of the operating frequency, and significantly improves the stability and performance indicators of the entire test system.

[0016] 2) While achieving high system directivity, this solution defines the isolated end of the single directional coupler that is terminated with a matching load as an additional coupling port to become a dual directional coupler. In this way, a single dual directional coupler can achieve the functional requirements of two single directional couplers in the signal distribution circuit of a traditional vector network analyzer, which can reduce costs and size to a certain extent. At the same time, the attenuation plate with excellent return loss added to the coupling arm of the dual directional coupler can reduce the mutual influence of the two coupling ports;

[0017] 3) The reference amplifier matrix can compensate for the insertion loss of the attenuator and the reference switch matrix, so that the reference receiver signal-to-noise ratio remains relatively stable to avoid deteriorating the trace noise. In addition to similar functions, the measurement amplifier matrix can also improve the system dynamic range of the entire multi-port vector network analyzer. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a structural schematic diagram of a high system directional signal distribution circuit suitable for a multi-port vector network analyzer of the utility model;

[0020] Figure 2 This is a schematic diagram of the structure of a traditional multi-port vector network analyzer signal distribution circuit. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0023] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features thereof may be combined with each other.

[0024] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0025] In the description of the present utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the utility model product is usually placed when in use, or the positions or positional relationships commonly understood by those skilled in the art, which are only for the convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0026] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] The utility model discloses a high system directional signal distribution circuit suitable for a multi-port vector network analyzer, and its structural schematic diagram is as follows Figure 1 As shown, the signal distribution circuit includes an excitation source S1, a local oscillator source S2, a dual directional coupler group, a reference receiver branch, a test receiver branch and a test port.

[0028] The dual-directional coupler group includes at least two dual-directional couplers, the number of which is the same as the number of designed test ports. The through input end of each dual-directional coupler is connected to the excitation source S1 through an excitation source switch matrix. The excitation source switch matrix is ​​used to control the on-off of the signal path between the corresponding dual-directional coupler and the excitation source S1. There are at least two reference receiver branches, each of which is used to mix the output signal of the reference coupling end of the dual-directional coupler with the local oscillator S2 and send it to the reference receiver. There are also at least two test receiver branches, each of which is used to mix the output signal of the measurement coupling end of the dual-directional coupler with the local oscillator S2 and send it to the measurement receiver. The test port is connected to the through output end of the dual-directional coupler.

[0029] By adopting the above solution, an independent single dual directional coupler is equipped at each external test port. The dual directional coupler can directly obtain the reference signal and the measurement signal reflected or transmitted by the device under test. There is no additional matrix RF switch between the coupler and the device under test. The reduction in insertion loss greatly improves the system directivity, increases the upper limit of the operating frequency, and significantly improves the stability and performance indicators of the entire test system.

[0030] By adopting the structure of the above signal distribution circuit, while obtaining high system directivity, the isolation end of the single directional coupler terminated with a matching load is defined as an additional coupling port to become a dual directional coupler. In this way, a single dual directional coupler can realize the functional requirements of two single directional couplers in the signal distribution circuit of the traditional vector network analyzer, which can reduce costs and size to a certain extent. At the same time, the attenuation plate with excellent return loss on the coupling arm of the dual directional coupler can reduce the mutual influence of the two coupling ports.

[0031] The introduction of attenuators and switch matrices reduces the receiver signal-to-noise ratio on the one hand, and deteriorates the system dynamic range of the entire multi-port vector network analyzer on the other hand. Figure 1 As shown, the reference receiver branch includes a reference amplifier matrix, a reference switch matrix, a reference mixer, and a reference receiver connected in sequence. The reference amplifier matrix includes at least one reference amplifier and each reference amplifier is used to amplify the output signal of a reference coupling end of a dual directional coupler; the reference switch matrix includes at least one radio frequency switch and is used to control the conduction state between a reference amplifier and a reference mixer in the reference amplifier matrix; the reference mixer is used to mix the output signal of the reference switch matrix and the local oscillator source S2; and the reference receiver is used to receive the output signal of the reference mixer.

[0032] The measurement receiver branch includes a measurement amplification matrix, a measurement switch matrix, a measurement mixer, and a measurement receiver which are connected in sequence.

[0033] Among them, the measurement amplification matrix includes at least one measurement amplifier and each measurement amplifier is used to amplify the output signal of a dual directional coupler measurement coupling end; the measurement switch matrix includes at least one radio frequency switch and is used to control the conduction state between a measurement amplifier and a measurement mixer in the measurement amplification matrix; the measurement mixer is used to mix the output signal of the measurement switch matrix and the local oscillator source S2; the measurement receiver is used to receive the output signal of the measurement mixer.

[0034] The reference receiver branch and the test receiver branch respectively keep the signal-to-noise ratio of the reference receiver and the test receiver relatively stable to avoid deteriorating the trace noise by using an amplification matrix to compensate for the insertion loss of the attenuation plate and the switch matrix; and the measurement amplification matrix, in addition to similar functions, can also improve the system dynamic range of the entire multi-port vector network analyzer. The number of reference receiver branches and test receiver branches depends on the number of receivers, and the number of dual directional couplers corresponding to each reference receiver branch and test receiver branch can be adjusted according to specific design requirements.

[0035] It should be noted that the matrix mentioned in this solution means the arrangement and combination of repeated or similar devices to achieve a certain function, and is not limited to a specific location or specific layout, and is equivalent to similar descriptions such as array and group. Taking the reference amplifier matrix as an example, its description is equivalent to the reference amplifier array or reference amplifier group.

[0036] For example, Figure 1 There are four receivers, namely R1, R2, A, and B, so the reference receiver branch and the test receiver branch are divided into two branches respectively.

[0037] Exemplarily, the excitation source switch matrix is ​​used to support the passage state of the excitation source to be switched arbitrarily between N test ports. Port 1 of the dual directional coupler is a direct input port, port 2 is a direct output port, port 3 is a reference coupling port, and port 4 is a measurement coupling port. In order to reduce the mutual influence of the two coupling ports, an attenuation plate with an attenuation of 10dB and a return loss better than 30dB is added to each coupling arm.

[0038] There are two reference receiver branches. The reference amplifier matrix L1, the reference switch matrix K2, the reference mixer M1, and the reference receiver R1 constitute the first reference receiver branch, wherein the number of amplifiers in L1 and the number of switching channels supported in K2 should be equal to the number of corresponding dual directional couplers; the reference amplifier matrix L2, the reference switch matrix K3, the reference mixer M2, and the reference receiver R2 constitute the second reference receiver branch, wherein the number of amplifiers in L2 and the number of switching channels supported in K3 should be equal to the number of corresponding dual directional couplers.

[0039] There are two test receiver branches. The measurement amplifier matrix L3, the measurement switch matrix K4, the measurement mixer M3, and the test receiver A constitute the first test receiver branch, wherein the number of amplifiers in L3 and the number of switching channels supported in K4 should be equal to the number of corresponding dual directional couplers; the measurement amplifier matrix L4, the measurement switch matrix K5, the measurement mixer 4, and the test receiver B constitute the second test receiver branch, wherein the number of amplifiers in L4 and the number of switching channels supported in K5 should be equal to the number of corresponding dual directional couplers.

[0040] It should be noted that Figure 1 The local oscillator source S2 in is the same local oscillator source.

[0041] 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 high system directivity signal distribution circuit suitable for a multi-port vector network analyzer, characterized in that ,include: Excitation source S1; Local oscillator source S2; A dual directional coupler group, wherein the dual directional coupler group includes at least two dual directional couplers and the through input end of each dual directional coupler is connected to the excitation source S1 through an excitation source switch matrix; Reference receiver branches, the reference receiver branches have at least two, each reference receiver branch is used to mix the output signal of the reference coupling end of the dual directional coupler with the local oscillator source S2 and then send it to the reference receiver; A test receiver branch, wherein the test receiver branch has at least two branches, and each test receiver branch is used to respectively mix the output signal of the dual directional coupler measurement coupling end with the local oscillator source S2 and then send the mixed signal to the measurement receiver; A test port is connected to the through output end of the dual directional coupler.

2. A high system directivity signal distribution circuit suitable for a multi-port vector network analyzer according to claim 1, characterized in that: The reference receiver branch comprises: A reference amplification matrix, wherein the reference amplification matrix includes at least one reference amplifier and each reference amplifier is used to amplify an output signal of a reference coupling end of a dual directional coupler; A reference switch matrix, the reference switch matrix comprising at least one radio frequency switch and used to control the conduction state between a reference amplifier and a reference mixer in the reference amplifier matrix; A reference mixer, the reference mixer being used to mix the reference switch matrix output signal and the local oscillator source S2; A reference receiver is used to receive the output signal of the reference mixer.

3. The high system directivity signal distribution circuit suitable for a multi-port vector network analyzer according to claim 1, characterized in that: The measuring receiver branch comprises: A measurement amplification matrix, wherein the measurement amplification matrix comprises at least one measurement amplifier and each measurement amplifier is used to amplify an output signal of a measurement coupling end of a dual directional coupler; A measurement switch matrix, the measurement switch matrix comprising at least one radio frequency switch and used to control the conduction state between a certain measurement amplifier and a measurement mixer in the measurement amplifier matrix; A measuring mixer, the measuring mixer being used to mix the measuring switch matrix output signal and the local oscillator source S2; A measuring receiver is used to receive the output signal of the measuring mixer.

4. The high system directivity signal distribution circuit suitable for a multi-port vector network analyzer according to claim 1, characterized in that: There are at least two reference receiver branches and test receiver branches, and the specific number depends on the number of receivers.

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