Line loss measurement method, device and system

Abstract

The embodiment of the application relates to the technical field of radio frequency test, and discloses a line loss measurement method, device and system, which are applied to a line loss measurement system, the line loss measurement system comprises an open circuit board, a short circuit board and a detection equipment, the open circuit board comprises first impedance tracks with both ends open; the short circuit board comprises second impedance tracks with one end grounded and the other end open; the line loss measurement method comprises the following steps: one end of the first impedance track on the open circuit board is connected with one end of a to-be-measured radio frequency line, the detection equipment is connected with the other end of the to-be-measured radio frequency line, and a first line loss value of the to-be-measured radio frequency line at a preset frequency point is acquired through the detection equipment; the open circuit end of the second impedance track on the short circuit board is connected with one end of the to-be-measured radio frequency line, the detection equipment is connected with the other end of the to-be-measured radio frequency line, and a second line loss value of the to-be-measured radio frequency line at the preset frequency point is acquired through the detection equipment; and the line loss value of the to-be-measured radio frequency line is obtained by calculating the average value of the first line loss value and the second line loss value.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the technical field of radio frequency test, in particular to a line loss measurement method, device and system. BACKGROUND

[0002] In the process of radio frequency test, since the ideal lossless connection between the device under test and the detection instrument cannot be achieved, it will inevitably cause the radio frequency line loss, which affects the accuracy of the radio frequency test of the device under test. The greater the radio frequency line loss, the greater the performance error measured by the detection instrument. Therefore, before the radio frequency test of the device under test, the radio frequency line loss between the device under test and the detection instrument needs to be measured first, and then the corresponding compensation is made in the detection instrument according to the line loss value of the radio frequency line, so as to solve the problem of inaccurate radio frequency test.

[0003] At present, the network analyzer is commonly used to measure the line loss value of the radio frequency line. The measurement process is as follows: the two ends of the radio frequency line are connected to the port 1 and the port 2 of the network analyzer respectively, and then a suitable test mode (such as S11 mode or S21 mode) is selected. According to the network analyzer, the insertion loss of the radio frequency line is obtained, which is approximately equal to the line loss value.

[0004] However, the above measurement method needs to provide a detection device (such as a network analyzer) for each radio frequency line to be tested. When a large number of radio frequency lines are measured, a large number of detection devices are needed, which is low in efficiency and high in cost, and is not suitable for factory environment for mass measurement. In addition, the radio frequency line in the factory environment is generally in a single open circuit state, and at this time, the two ends of the radio frequency line cannot be connected to the detection device. SUMMARY

[0005] The purpose of the embodiments of the present application is to provide a line loss measurement method, device and system. The two ends of the radio frequency line to be tested are connected to the open circuit board and the detection device respectively, and the two ends of the radio frequency line to be tested are connected to the short circuit board and the detection device respectively. The return loss of the open circuit board and the short circuit board cooperates with the detection device to efficiently and accurately complete the measurement of the line loss. Only one end of the radio frequency line to be tested needs to be connected during each measurement, which is convenient for application in the line loss measurement in the factory environment with large quantities.

[0006] To solve the above technical problems, the embodiment of the present application provides a line loss measurement method, which is applied to a connection device in a test system, and the line loss measurement system comprises an open circuit board, a short circuit board and a detection device, the open circuit board comprises a first impedance trace with both ends open circuit, the short circuit board comprises a second impedance trace with one end grounded and the other end open circuit, the line loss measurement method comprises that one end of the first impedance trace on the open circuit board is connected with one end of a to-be-tested radio frequency line, the detection device is connected with the other end of the to-be-tested radio frequency line, and a first line loss value of the to-be-tested radio frequency line at a preset frequency point is obtained through the detection device; the open circuit end of the second impedance trace on the short circuit board is connected with one end of the to-be-tested radio frequency line, the detection device is connected with the other end of the to-be-tested radio frequency line, and a second line loss value of the to-be-tested radio frequency line at the preset frequency point is obtained through the detection device; and the average value of the first line loss value and the second line loss value is calculated to obtain the line loss value of the to-be-tested radio frequency line.

[0007] The embodiment of the present application further provides a line loss measurement device, which is characterized in that comprising an open circuit board and a short circuit board.

[0008] The open circuit board comprises a first impedance trace arranged on one side surface of a substrate, and the first impedance trace has both ends open circuit.

[0009] The short circuit board comprises a second impedance trace arranged on one side surface of a substrate, and the second impedance trace has one end grounded and the other end open circuit.

[0010] The embodiment of the present application further provides a line loss measurement system, which comprises the open circuit board as described in the above embodiment, the short circuit board as described in the above embodiment, a clamp and a detection device.

[0011] The clamp is used for connecting one end of the first impedance trace on the open circuit board and the to-be-tested radio frequency line respectively, and connecting the open circuit end of the second impedance trace on the short circuit board and the to-be-tested radio frequency line respectively.

[0012] The detection device is used for connecting the other end of the to-be-tested radio frequency line when the open circuit board is connected with one end of the to-be-tested radio frequency line through the clamp, and obtaining a first line loss value of the to-be-tested radio frequency line at a preset frequency point, and is used for connecting the other end of the to-be-tested radio frequency line when the short circuit board is connected with one end of the to-be-tested radio frequency line through the clamp, and obtaining a second line loss value of the to-be-tested radio frequency line at the preset frequency point.

[0013] The line loss measurement method provided by the embodiment of the application connects one end of the first impedance trace on the open circuit board with one end of the to-be-measured radio frequency line, connects the other end of the to-be-measured radio frequency line with the detection device, and directly obtains a first line loss value of the to-be-measured radio frequency line at a preset frequency point by the detection device. Then, the open circuit end of the second impedance trace on the short circuit board is connected with one end of the to-be-measured radio frequency line, the other end of the to-be-measured radio frequency line is connected with the detection device, and a second line loss value of the to-be-measured radio frequency line at the same frequency point is directly obtained by the detection device. The average value of the first line loss value and the second line loss value is calculated, and the line loss value of the to-be-measured radio frequency line is obtained. Since the phase difference of the return loss of the open circuit board and the return loss of the short circuit board at the same frequency point is 180°, it can be simply regarded as a differential signal, that is, regardless of the amplitude change of the return loss of the open circuit board and the short circuit board, the average value at the same frequency point remains basically unchanged. Thus, the return loss of the radio frequency line can be stably and accurately obtained through the differential return loss, and the method does not contain any active or passive device, and the test process does not need power supply. Only one end of the radio frequency line is connected with the detection device, and the measurement process can be completed, which is convenient and fast, and is suitable for factory environment for mass testing. BRIEF DESCRIPTION OF DRAWINGS

[0014] One or more embodiments are illustrated by way of example in the figures that form a part of this disclosure and which are shown by way of example, not limitation in the figures of the accompanying drawings in which like references indicate similar elements and in which:

[0015] Figure 1 is a flowchart of the line loss measurement method provided by the embodiment of the application;

[0016] Figure 2 is a structural schematic diagram of the open circuit board 200 in the line loss measurement device provided by the embodiment of the application;

[0017] Figure 3 is a structural schematic diagram of the short circuit board 300 in the line loss measurement device provided by the embodiment of the application Figure 1 ;

[0018] Figure 4 is a structural schematic diagram of the short circuit board 300 in the line loss measurement device provided by the embodiment of the application Figure 2 ;

[0019] Figure 5 is a structural schematic diagram of the line loss measurement system provided by the embodiment of the application Figure 1 ;

[0020] Figure 6 is a structural schematic diagram of the line loss measurement system provided by the embodiment of the application Figure 2 . DETAILED DESCRIPTION

[0021] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the various embodiments of the present application will be described in detail below with reference to the drawings. However, those skilled in the art can understand that, in the various embodiments of the present application, many technical details are presented in order to make the readers better understand the present application. However, the technical solutions claimed by the present application can be implemented even without these technical details and various changes and modifications based on the following embodiments. The division of the following various embodiments is for the convenience of description, and should not constitute any limitation on the specific implementation of the present application, and the various embodiments can be combined and referenced with each other without contradiction.

[0022] The embodiments of the present application relate to a line loss measurement method applied to a line loss measurement system, the line loss measurement system comprising: an open circuit board, a short circuit board and a detection device, the open circuit board comprising: a first impedance trace with both ends open circuit; the short circuit board comprising: a second impedance trace with one end grounded and the other end open circuit; the specific flow of the test method is as shown in Figure 1 , comprising:

[0023] Step 101, one end of the first impedance trace on the open circuit board is connected with one end of the to-be-tested radio frequency line, the detection device is connected with the other end of the to-be-tested radio frequency line, and the first line loss value of the to-be-tested radio frequency line at a preset frequency point is obtained through the detection device.

[0024] In this embodiment, the to-be-tested radio frequency line is connected with one end of the first impedance trace on the open circuit board and the detection device respectively, and the first line loss value of the to-be-tested radio frequency line at a preset frequency point can be directly read through the detection device. The detection device can be a network analyzer, or other instruments or devices capable of transmitting power and detecting power.

[0025] Step 102, the open circuit end of the second impedance trace on the short circuit board is connected with one end of the to-be-tested radio frequency line, the detection device is connected with the other end of the to-be-tested radio frequency line, and the second line loss value of the to-be-tested radio frequency line at a preset frequency point is obtained through the detection device.

[0026] Specifically, after the measurement of the first line loss value is completed, the connection between the open circuit board and the to-be-tested radio frequency line is disconnected, the second impedance trace on the short circuit board is connected with the to-be-tested radio frequency line, and the second line loss value of the to-be-tested radio frequency line at the same frequency point is measured.

[0027] It should be noted that for a lossy line, there is a certain degree of mismatch between the source power and the power transmitted to the transmission line, which is defined as the return loss: RL = -10log(Pr / Pi), which is the ratio of reflected power to input power. In theory, when the circuit is in an open or short circuit state, the power input to the transmission line will be completely reflected, at which time the return loss should be 0 dB; in practice, the transmission line has a path loss, meaning that Pr / Pi≠1, which is reflected in S11 (reflection coefficient, i.e., return loss), that is, S11<0 dB; therefore, the S11 presented on the network analyzer in the open or short circuit state can be converted to the line loss, that is, Pathloss = S 11 / 2(dB).

[0028] In a factory environment, the radio frequency line is generally in a single-ended open circuit state, but the line loss value fluctuates greatly in the open circuit state, making the line loss value of the radio frequency line measured at the same frequency point by different instruments in different environments differ greatly, that is, the line loss value of the radio frequency line cannot be stably and accurately obtained. Based on this, the present application uses an open circuit board and a short circuit board to measure the line loss, and since the phase difference of the return loss of the open circuit board and the return loss of the short circuit board at the same frequency point is 180 degrees, it can be simply regarded as a kind of differential signal, that is, regardless of the amplitude of the return loss of the open circuit board and the return loss of the short circuit board, the mean value thereof at the same frequency point remains basically unchanged, so that the line loss value of the radio frequency line can be stably and accurately obtained through the return loss with such a differential property.

[0029] In addition, the phase difference of the return loss of the open circuit board and the return loss of the short circuit board is theoretically 180 degrees, but in practice, it has a slight error from 180 degrees, so the present application controls the phase difference of the return loss of the open circuit board and the return loss of the short circuit board to be 180 degrees through the length of the first impedance trace and the length of the second impedance trace. However, if the impedance trace is too long, the trace itself will have line loss, affecting the measurement result, so the length of the impedance trace should be as short as possible, and in theory, the impedance trace can even be a point, but the impedance trace is too short to control the phase difference to be 180 degrees. Therefore, the length of the first impedance trace and the length of the second impedance trace need to be within a reasonable range. The length of the first impedance trace and the length of the second impedance trace can be the same or different, which is not limited herein.

[0030] Step 103, calculating the average of the first line loss value and the second line loss value to obtain the line loss value of the to-be-measured radio frequency line.

[0031] Specifically, a stable and accurate line loss value of the to-be-measured radio frequency line can be obtained according to the average of the first line loss value and the second line loss value. The entire measurement method only needs to use the open circuit board and the short circuit board, without using any active or passive devices, and the test process does not need power supply, and only one end of the radio frequency line needs to be connected to the detection equipment to complete the measurement. If the detection equipment has multiple detection ports, multiple radio frequency lines can be measured simultaneously, which is suitable for large-scale testing.

[0032] In an embodiment, the line loss measurement system further comprises a clamp, one end of the first impedance trace on the open circuit board is connected to one end of the radio frequency line to be measured through the clamp, and the open end of the second impedance trace on the short circuit board is connected to one end of the radio frequency line to be measured through the clamp. The clamp in this embodiment can be of any structure as long as it can connect the first impedance trace on the open circuit board (or the second impedance trace on the short circuit board) to the radio frequency line to be measured.

[0033] The line loss measurement method provided by the embodiments of the present application connects one end of the first impedance trace on the open circuit board to one end of the radio frequency line to be measured, connects the other end of the radio frequency line to be measured to the detection device, and directly obtains the first line loss value of the radio frequency line to be measured at a preset frequency point by the detection device. Then, the open end of the second impedance trace on the short circuit board is connected to one end of the radio frequency line to be measured, the other end of the radio frequency line to be measured is connected to the detection device, and the second line loss value of the radio frequency line to be measured at the same frequency point is directly obtained by the detection device. The average value of the first line loss value and the second line loss value is calculated, and the line loss value of the radio frequency line to be measured is obtained. Since the phase difference of the return loss of the open circuit board and the return loss of the short circuit board at the same frequency point is 180°, it can be simply regarded as a kind of differential signal, that is, regardless of the amplitude change of the return loss of the open circuit board and the short circuit board, the average value at the same frequency point remains basically unchanged. Thus, the line loss value of the radio frequency line can be stably and accurately obtained through the return loss with this differential property, and this method does not contain any active or passive devices, and the test process does not need power supply. Only one end of the radio frequency line needs to be connected to the detection device to complete the measurement process, which is convenient and fast, and is suitable for factory environment for mass testing.

[0034] Those skilled in the art can understand that all or part of the steps of the above-mentioned embodiment methods can be completed by programs instructing related hardware, the programs are stored in a storage medium, and the programs include a plurality of instructions for making a device (which can be a single-chip microcomputer, a chip, etc.) or a processor execute all or part of the steps of the methods described in various embodiments of the present application. The foregoing storage medium includes a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various storage medium that can store program codes.

[0035] In addition, the division of steps of the above various methods is only for the purpose of clear description, and when implemented, one step can be combined or some steps can be split or decomposed into multiple steps, as long as the same logical relationship is included, all are within the protection scope of the present patent; adding irrelevant modifications or introducing irrelevant designs in the algorithm or flow, but not changing the core design of the algorithm and flow, are within the protection scope of the present patent.

[0036] The embodiment of the present application also relates to a line loss measuring device applied to a connecting device in a test system, such as Figure 2 and Figure 3 The measuring device includes an open circuit board 200 and a short circuit board 300.

[0037] The open circuit board 200 includes a first impedance trace 201 arranged on one side surface of a substrate, and the two ends of the first impedance trace 201 are open circuit.

[0038] The short circuit board 300 includes a second impedance trace 301 arranged on one side surface of a substrate, and one end of the second impedance trace 301 is grounded and the other end is open circuit.

[0039] It should be noted that there are many grounding methods in the field of PCB design, and for a copper-clad substrate, the copper-clad area is generally used as a ground plane. The two ends of the first impedance trace 201 are open circuit, that is, the two ends of the first impedance trace are not connected to any copper-clad area (ground plane). One end of the second impedance trace 301 is connected to the copper-clad area (ground plane) and the other end is not connected to the copper-clad area (ground plane). Of course, the grounding method of the short circuit board can also use other methods, which are not limited in the present embodiment.

[0040] Further, as shown in Figure 4 The short circuit board 300 further includes a via 302 arranged on one side surface of a substrate, and the other side surface of the substrate is a ground plane 303; the via is filled with a conductive medium, and one end of the second impedance trace 301 is connected to the ground plane 303 through the via 302 filled with the conductive medium.

[0041] Specifically, a via 302 is punched on one side of the substrate where the second impedance trace 301 is located, the via 302 is filled with a conductive medium, and the second impedance trace 301 is short-circuited with the ground plane on the other side of the substrate through the via 302.

[0042] In the present embodiment, the lengths of the first impedance trace 201 and the second impedance trace 301 are both within the range of 1-10 mm, so as to control the phase difference of the return loss of the open circuit board 200 and the short circuit board 300 within 180°±35°. In addition, the length of the first impedance trace and the length of the second impedance trace can be the same or different, as long as they are within the range of 1-10 mm. The width of the first impedance trace 201 is less than the length of the first impedance trace 201, and the width of the second impedance trace 301 is less than the length of the second impedance trace 301. The impedance values of the first impedance trace 201 and the second impedance trace 301 are the impedance values when the line loss measuring system is impedance matched.

[0043] Specifically, the impedance values of the first impedance trace and the second impedance trace are the impedance values when the entire line loss measurement system, i.e., the entire transmission line from the detection device to the open-circuit board or the short-circuit board, is impedance-matched. If the entire system impedance is mismatched, the line loss measurement result will be affected, resulting in inaccurate line loss measurement values.

[0044] Embodiments of the present application also relate to a line loss measurement system, as shown in Figure 5 and Figure 6 comprising an open-circuit board 200, a short-circuit board 300, a clamp 400, and a detection device 500.

[0045] The clamp 400 is used to connect one end of the first impedance trace 201 on the open-circuit board 200 and the to-be-measured radio frequency line, respectively, and to connect the open-circuit end of the second impedance trace 301 on the short-circuit board 300 and the to-be-measured radio frequency line, respectively.

[0046] The detection device 500 is used to connect the other end of the to-be-measured radio frequency line when the open-circuit board 200 is connected to one end of the to-be-measured radio frequency line through the clamp 400, and to obtain a first line loss value of the to-be-measured radio frequency line at a preset frequency point, and to connect the other end of the to-be-measured radio frequency line when the short-circuit board 300 is connected to one end of the to-be-measured radio frequency line through the clamp 400, and to obtain a second line loss value of the to-be-measured radio frequency line at a preset frequency point.

[0047] Further, the clamp 400 comprises a first connecting portion 401 and a second connecting portion 402; wherein the first connecting portion 401 is used to connect the open-circuit board 200 or the short-circuit board 300; and the second connecting portion 402 is used to connect the to-be-measured radio frequency line.

[0048] Further, the first connecting portion 401 comprises a first thimble 4011 and a second thimble 4012.

[0049] The first thimble 4011 is used to make full contact with one end of the first impedance trace 201 or the open-circuit end of the second impedance trace 301; and the second thimble 4012 is used to make full contact with the ground plane of the open-circuit board 200 or the short-circuit board 300.

[0050] It should be noted that the first thimble 4011 is used to connect the first impedance trace 201 or the second impedance trace 301, and the second thimble 4012 is used to connect the ground plane of the open-circuit board 200 or the short-circuit board 300 to realize true grounding. Generally speaking, taking a copper-clad substrate as an example, the copper-clad area can be considered as a ground plane, so the areas of the open-circuit board 200 other than the first impedance trace 201 can be considered as a ground plane, and true grounding is realized by making the second thimble 4012 on the clamp 400 fully contact with the ground plane of the open-circuit board. Similarly, the short-circuit board 300 also realizes true grounding through the second thimble 4012 on the clamp.

[0051] It can be found that the embodiment is a system embodiment corresponding to the implementation of the line loss measurement method, and therefore the implementation can be implemented in cooperation with the implementation of the above-mentioned test method. The related technical details mentioned in the above implementation are still valid in the present implementation, and in order to reduce repetition, they will not be described here. Accordingly, the related technical details mentioned in the present implementation can also be applied in the above method implementation.

[0052] It should be noted that the line loss measurement device provided in the present embodiment only describes the main modules, and does not mean that it does not include other basic modules or units for realizing the line loss measurement method of the present application.

[0053] Those skilled in the art can understand that the above-mentioned embodiments are specific embodiments for realizing the present application, and in actual application, various changes can be made in form and details without departing from the spirit and scope of the present application.

Claims

1. A method for measuring line loss, characterized in that, This invention is applied to a line loss measurement system, which includes an open-circuit board, a short-circuit board, and a testing device. The open-circuit board includes a first impedance trace with both ends open. The short-circuit board includes a second impedance trace with one end grounded and the other end open. The lengths of both the first impedance trace and the second impedance trace are in the range of 1-10 mm. The line loss measurement method includes: One end of the first impedance trace on the open circuit board is connected to one end of the radio frequency line under test, and the detection device is connected to the other end of the radio frequency line under test. The detection device is used to obtain the first line loss value of the radio frequency line under test at a preset frequency point. One open end of the second impedance trace on the short-circuit board is connected to one end of the radio frequency line under test, and the detection device is connected to the other end of the radio frequency line under test. The detection device is used to obtain the second line loss value of the radio frequency line under test at the preset frequency point. The average of the first line loss value and the second line loss value is calculated to obtain the line loss value of the radio frequency line under test.

2. The line loss measurement method according to claim 1, characterized in that, The line loss measurement system also includes: a clamp; One end of the first impedance trace on the open circuit board is connected to one end of the RF line under test, including: One end of the first impedance trace on the open circuit board is connected to one end of the radio frequency line under test via the clamp. The open end of the second impedance trace on the short-circuit board is connected to one end of the radio frequency line under test, including: One open end of the second impedance trace on the short-circuit board is connected to one end of the radio frequency line under test via the clamp.

3. A line loss measuring device, characterized in that, include: Open circuit board and short circuit board; The open circuit board includes: a first impedance trace disposed on one side surface of the substrate, wherein the first impedance trace is open at both ends; The short-circuit board includes: a second impedance trace disposed on one side surface of the substrate, one end of the second impedance trace being grounded and the other end being open; wherein the lengths of the first impedance trace and the second impedance trace are both in the range of 1-10mm.

4. The line loss measuring device according to claim 3, characterized in that, The short-circuit board further includes: a via disposed on one side surface of the substrate, and the other side surface of the substrate is a ground plane; the via is filled with a conductive medium, and one end of the second impedance trace is connected to the ground plane through the via filled with the conductive medium.

5. The line loss measuring device according to claim 3, characterized in that, The width of the first impedance trace is less than the length of the first impedance trace, and the width of the second impedance trace is less than the length of the second impedance trace.

6. The line loss measuring device according to any one of claims 3-5, characterized in that, The line loss measuring device is applied to the line loss measuring system; the impedance values ​​of the first impedance trace and the second impedance trace are the impedance values ​​when the line loss measuring system is impedance matched.

7. A line loss measurement system, characterized in that, include: Fixtures, testing equipment, and line loss measuring devices as described in any one of claims 3-6; The clamp is used to connect one end of the first impedance trace on the open circuit board and the radio frequency line under test, and to connect one open end of the second impedance trace on the short circuit board and the radio frequency line under test. The testing device is used to connect to the other end of the RF line under test when the open circuit board is connected to one end of the RF line under test through the clamp, and to obtain the first line loss value of the RF line under test at a preset frequency point; and to connect to the other end of the RF line under test when the short circuit board is connected to one end of the RF line under test through the clamp, and to obtain the second line loss value of the RF line under test at a preset frequency point.

8. The line loss measurement system according to claim 7, characterized in that, The clamp includes: a first connecting part and a second connecting part; The first connecting part is used to connect the open circuit board or the short circuit board; The second connection part is used to connect the radio frequency line under test.

9. The line loss measurement system according to claim 8, characterized in that, The first connecting part includes: a first ejector pin and a second ejector pin; The first ejector pin is used to make full contact with one end of the first impedance trace, or to make full contact with the open end of the second impedance trace; The second pin is used to make full contact with the ground plane of the open circuit board or short circuit board.

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