Chip antenna single-path probe feed calibration system and method
The insertion loss of each probe in the chip antenna test is calculated by directly passing through three probes, which solves the problem of link loss calibration between the GSG probe and the waveguide port and improves the accuracy of the chip antenna test.
Patent Information
- Application Number
- CN202411941479.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-26
- Publication Date
- 2025-04-18
AI Technical Summary
The prior art is difficult to calibrate link loss between the GSG probe and the waveguide port in chip antenna testing, especially in the millimeter wave and terahertz bands.
The S21 reading between probes is obtained through the vector network analyzer, the insertion loss of each probe is calculated, and the overall link loss is calculated.
It solves the problem of inaccurate link loss calibration in chip antenna test, improves the accuracy of chip antenna gain and directional pattern test, and overcomes the disadvantages of the failure of the existing technology to calibrate the GSG-waveguide link.
Smart Images
Figure CN119846322A_ABST
Abstract
Description
Background Art
[0002] Chip antennas are made by using CMOS technology to tape out antennas on wafers and integrate them with integrated circuits in the wafers. Compared with traditional planar antennas, they reduce signal transmission links, so they have advantages such as low high-frequency loss, high integration, and small size. They are widely used in array radar, satellite communications, remote sensing and other fields. Usually, the characteristic that the atmosphere absorbs wireless signals at a peak frequency of around 60GHz is used to ensure the security and anti-interference of chip antennas in short-distance transmission of electromagnetic communication signals. For example, a certain unit in the United States has developed a two-dimensional phased array chip antenna for satellite communications, such as Figure 4 As shown, the chip integrates 4096 nanoantennas onto a silicon substrate and is only the size of a pinhead.
[0003] Compared with traditional antennas, chip antennas are usually fed by GSG probes, which is completely different from traditional waveguide or coaxial feeding methods. During antenna calibration, it is usually necessary to calibrate the link at the front end of the antenna first to ensure the accuracy of antenna gain measurement.
[0004] In the prior art, calibration can be performed between two waveguide ports by using calibration pieces, and two GSG mode probes can also be calibrated by using a dedicated TRL calibration piece. Bianco et al. conducted theoretical research on the de-embedding method, but it has not been widely used due to the imperfect theory. Franzen and Speciale proposed thru-short-delay (TSD) calibration, which realizes the de-embedding of the transfer leads at both ends by setting three types of calibration pieces: thru, short circuit, and delay. Engen and Hoer improved on the basis of TSD calibration and proposed thru-reflect-delay line (TRL) calibration. The main difference between this method and TSD calibration is that the reflection calibration piece can be an ideal short circuit or open circuit. TRL calibration is widely used in microwave component de-embedding test and vector network analyzer calibration work because the calibration piece is simple to make. A simplified model of TRL calibration, thru-line (TL) calibration, is proposed. When the transfer leads at both ends are symmetrical, the reflection calibration piece is no longer required. Corresponding improvements were made to the TRL calibration and applied to the test of diodes, providing ideas for applying TRL calibration to test RF cables with non-standard interfaces.
[0005] However, for the millimeter-wave and even terahertz frequency bands in which chip antennas operate, receiving antennas usually also adopt waveguide port form, which makes it difficult to calibrate the link loss of the chip antenna front end using existing mature solutions. Therefore, it is necessary to design a new calibration scheme to calibrate the link loss in the chip antenna test. Summary of the invention
[0006] This specification provides a chip antenna single-channel probe feeding calibration method to solve the technical problem that the link cannot be calibrated when the GSG probe is fed, that is, the feeding port of the chip antenna to be tested is a GSG probe, and the receiving antenna is a standard gain antenna fed by a waveguide. The existing technology cannot solve the technical problem of link loss calibration when the two ports cannot be directly connected.
[0007] To achieve the above object, the present invention adopts the following technical solution:
[0008] In the first aspect of the present specification, a chip antenna single-channel probe feeding calibration system is provided, which is based on a chip antenna measurement and calibration device, wherein the chip antenna measurement and calibration device comprises a radio frequency signal subsystem, a chip antenna feeding platform and a three-dimensional scanning subsystem; the radio frequency signal subsystem comprises a vector network analyzer, and the system comprises: an air-floating frame platform, a probe platform, a stage, two probe seats, a microscope, and two spectrum spreading modules:
[0009] The probe station is arranged on the air-floating frame platform;
[0010] The stage and the two probe seats are arranged on the probe platform; the two probe seats are located on both sides of the stage; the stage is used to place a straight-through calibration sheet; the straight-through calibration sheet is provided with a GSG feeding port;
[0011] The side of each probe seat close to the straight-through calibration sheet is used to place the probe; the probe is connected to the straight-through calibration sheet; the side of each probe seat away from the straight-through calibration sheet is used to place the spectrum expansion module; the spectrum expansion module placed on each probe seat is connected to the probe during the feed calibration;
[0012] The microscope is arranged above the through calibration sheet; the microscope is used to locate the position of each probe;
[0013] The probe seat is used to adjust its position according to the position of the probe so that the probe placed thereon is in good contact with the GSG feeding port of the through calibration plate for feeding;
[0014] The vector network analyzer is connected to the two spectrum spreading modules; the vector network analyzer is used for obtaining S21 readings of two probes passing through each other during feed calibration, and then calculating the insertion loss of each probe.
[0015] In some preferred embodiments, when the displacement of each probe on the through calibration piece is greater than one quarter of the needle tip length, the two are in good contact.
[0016] In some preferred implementations, when performing feed calibration, three probes are connected in pairs to obtain the insertion loss of a single probe.
[0017] In some preferred embodiments, the S 21 The relationship between the reading and the insertion loss of a single probe is:
[0018]
[0019] Where A1 is the S of the vector network analyzer when probe 1 and probe 2 are connected directly. 21 A2 is the S reading of the vector network analyzer when probe 1 and probe 3 are connected directly. 21 A3 is the S reading of the vector network analyzer when probe 2 and probe 3 are connected directly. 21 Read the following: T1 is the insertion loss of probe 1, T2 is the insertion loss of probe 2, and T3 is the insertion loss of probe 3.
[0020] In some preferred embodiments, the insertion loss of each probe is calculated as follows:
[0021] In some preferred embodiments, the microscope is mounted on a slide rail, and when the positions of the probes are positioned, the microscope is moved away from the through-calibration plate.
[0022] In some preferred embodiments, when performing feeding calibration, the feeding port of the chip antenna to be tested is a GSG probe feeding port.
[0023] In some preferred embodiments, when performing feeding calibration, the feeding port of the receiving antenna in the chip antenna measurement and calibration device is a waveguide feeding port.
[0024] In some preferred embodiments, when performing feed calibration, equipment other than the probe and adapter cable is calibrated first.
[0025] In a second aspect of the present specification, a chip antenna single-channel probe feeding calibration method is provided. Based on the above-mentioned chip antenna single-channel probe feeding calibration system method, the method includes:
[0026] Step S1, open the vector network, adjust the frequency multiplication times and the transmission power, set the test frequency, adjust the intermediate frequency bandwidth, and calibrate the vector network and the spread spectrum module to the two waveguide calibration end faces;
[0027] Step S2, after calibration, placing the through calibration piece on the stage, and using the microscope to locate the positions of the probe 1 and the probe 2, and then adjusting the probe seat so that each probe is in good contact with the through calibration piece;
[0028] Step S3, obtaining the S of the vector network analyzer when the probe 1 and the probe 2 are directly connected21 Read the value, recorded as A1;
[0029] Step S4, replace the probe 2 with the probe 3, repeat the method of step S2, and obtain the S of the vector network analyzer when the probe 1 and the probe 3 are directly connected. 21 The reading is recorded as A2;
[0030] Step S5, replacing the probe 1 with the probe 2, repeating the method of step S2, and obtaining the S of the vector network analyzer when the probe 2 and the probe 3 are directly connected. 21 Read the value, record it as A3;
[0031] Step S6, combining A1 and A 12 , said A3, calculates the insertion loss of each probe.
[0032] At least one of the above technical solutions adopted in the embodiments of this specification can achieve the following beneficial effects:
[0033] The present invention obtains the insertion loss of a single probe by using three probes in a pairwise direct connection manner, and calculates it into the overall link loss, thereby solving the problem of inaccurate link loss calibration during chip antenna testing, improving the accuracy of chip antenna gain and radiation pattern testing to a certain extent, and solving the problem that the prior art cannot calibrate the GSG-waveguide link. BRIEF DESCRIPTION OF THE DRAWINGS
[0034] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:
[0035] Figure 1 A schematic diagram of a chip antenna single-channel probe feeding calibration system provided in an embodiment of this specification;
[0036] Figure 2 A schematic diagram of a chip antenna measurement and calibration device according to an embodiment of this specification;
[0037] Figure 3 A schematic diagram of a single-channel probe insertion loss calibration process provided in an embodiment of this specification;
[0038] Figure 4 A schematic diagram of a two-dimensional phased array chip antenna provided in accordance with an embodiment of this specification. DETAILED DESCRIPTION
[0039] In order to make the purpose, technical solution and advantages of the present application clearer, the technical solution of the present application will be clearly and completely described below in combination with the specific embodiments of the present application and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.
[0040] The technical solutions provided by various embodiments of the present application are described in detail below in conjunction with the accompanying drawings.
[0041] Chip antenna is a new type of antenna, and its feeding method is usually GSG probe feeding. The receiving antenna of the millimeter wave band usually uses waveguide feeding method. The existing calibration method can calibrate between waveguide ports, but the chip antenna test link will also introduce probe or adapter and cable loss according to the choice of probe. This makes it difficult to calibrate the link loss of the chip antenna front end using the existing mature solution, so it is necessary to design a new calibration solution to calibrate the link loss in the chip antenna test.
[0042] This specification designs a feeding calibration system for a single-channel probe of a chip antenna, and proposes a link calibration method for the chip antenna usage scenario (especially designing a calibration under the condition of two-port impedance mismatch), which solves the problem that the link cannot be calibrated when the GSG probe is fed, and to a certain extent makes the results of the chip antenna gain pattern test more accurate. Compared with the prior art, the present invention obtains the insertion loss of a single probe by using three probes in a pairwise direct connection, and calculates it into the overall link loss, thereby solving the problem of inaccurate link loss calibration during chip antenna testing, and to a certain extent improves the accuracy of chip antenna gain and pattern testing, and solves the problem of being unable to calibrate the GSG-waveguide link. The details are as follows:
[0043] The first embodiment of this specification provides a chip antenna single-path probe feeding calibration system, such as Figure 1 As shown, based on the chip antenna measurement and calibration device, the chip antenna measurement and calibration device includes a radio frequency signal subsystem, a chip antenna feeding platform and a three-dimensional scanning subsystem, such as Figure 2 As shown, a chip antenna single-channel probe feeding calibration system includes: an air-floating frame platform, a probe station, a stage, two probe seats, a microscope, and two spectrum spreading modules;
[0044] A probe station is set on the air-floating frame platform;
[0045] The probe platform is provided with a stage and the two probe seats; the two probe seats are located on both sides of the stage; the stage is used to place a straight-through calibration sheet; the straight-through calibration sheet is provided with a GSG feeding port (i.e., a feeding port of the chip antenna);
[0046] The side of each probe seat close to the straight-through calibration sheet is used to place the probe; the probe is connected to the straight-through calibration sheet; the side of each probe seat away from the straight-through calibration sheet is used to place the spectrum expansion module; the spectrum expansion module placed on each probe seat is connected to the probe during the feed calibration;
[0047] A microscope is arranged above the straight-through calibration sheet; the microscope is used to locate the position of each probe; the microscope is mounted on a slide rail, and when the position of each probe is located, the microscope is moved away from the straight-through calibration sheet (preferably out of the darkroom, i.e. Figure 1 The space enclosed by the triangle in the middle).
[0048] The probe seat is used to adjust the position of the probe according to its position, so that the probe placed on it is in good contact with the GSG feeding port of the straight-through calibration plate (preferably, when the displacement of each probe on the straight-through calibration plate is greater than one-quarter of the needle tip length, the two are in good contact) for feeding;
[0049] A vector network analyzer is connected to the two spectrum spreading modules; the vector network analyzer is used for obtaining S21 readings of two probes passing through each other during feed calibration, and then calculating the insertion loss of each probe.
[0050] When performing feed calibration, use the straight-through GSG calibration sheet to make three sets of probes pass through each other to obtain the S21 parameters of each group. Prepare three different sets of probes and test them through each other. By combining the following equations:
[0051]
[0052] Where A1 is the S of the vector network analyzer when probe 1 and probe 2 are connected directly. 21 A2 is the S reading of the vector network analyzer when probe 1 and probe 3 are connected directly. 21 A3 is the S reading of the vector network analyzer when probe 2 and probe 3 are connected directly. 21 Read the following: T1 is the insertion loss of probe 1, T2 is the insertion loss of probe 2, and T3 is the insertion loss of probe 3.
[0053] Then, by solving the equation, we can get the insertion loss of each probe:
[0054] It should be noted that the chip antenna single-channel probe feed calibration system provided in the above embodiment is only illustrated by the division of the above functional modules. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the modules or steps in the embodiments of the present invention can be decomposed or combined. For example, the modules in the above embodiments can be combined into one module, or further divided into multiple sub-modules to complete all or part of the functions described above. The names of the modules and steps involved in the embodiments of the present invention are only for distinguishing the modules or steps, and are not regarded as improper limitations on the present invention.
[0055] A second embodiment of the present specification provides a chip antenna single-channel probe feeding calibration method, based on the above-mentioned chip antenna single-channel probe feeding calibration system, the method includes:
[0056] Step S1, open the vector network, adjust the frequency multiplication times and the transmission power, set the test frequency, adjust the intermediate frequency bandwidth, and calibrate the vector network and the spread spectrum module to the two waveguide calibration end faces;
[0057] In this embodiment, the instrument is first connected, the vector network is turned on, the corresponding frequency multiplication times and transmission power are adjusted, the test frequency is set, the intermediate frequency bandwidth is adjusted, and the vector network and the spectrum expansion module are calibrated to the two waveguide calibration end faces.
[0058] Step S2, after calibration, placing the through calibration piece on the stage, and using the microscope to locate the positions of the probe 1 and the probe 2, and then adjusting the probe seat so that each probe is in good contact with the through calibration piece;
[0059] In this embodiment, a straight-through calibration piece is placed, and the positions of probes 1 and 2 are located using a microscope. The positions of the probes are adjusted to the GSG feeding port positions of the straight-through calibration piece through the probe holder, and the Z-axis knob of the probe holder is adjusted to make the probes contact the GSG pads well (the probes are qualified when they are displaced on the pads by one-quarter of the needle tip length). At this time, the microscope is removed.
[0060] Step S3, obtaining the S of the vector network analyzer when the probe 1 and the probe 2 are directly connected 21 Read the value, recorded as A1;
[0061] Step S4, replace the probe 2 with the probe 3, repeat the method of step S2, and obtain the S of the vector network analyzer when the probe 1 and the probe 3 are directly connected. 21 The reading is recorded as A2;
[0062] Step S5, replacing the probe 1 with the probe 2, repeating the method of step S2, and obtaining the S of the vector network analyzer when the probe 2 and the probe 3 are directly connected.21 Read the value, record it as A3;
[0063] Step S6, combining A1 and A 12 , said A3, calculates the insertion loss of each probe.
[0064] In this embodiment, the vector network test S21 parameters are adjusted at this time, such as Figure 3 As shown, the insertion loss of a single probe is obtained by connecting three probes in pairs (the specific calculation formula of the insertion loss of a single probe can refer to the formula in the above system embodiment.). In the actual chip antenna test, after calibration to the waveguide end face, it can be calculated into the link loss. That is, the feeding port of the chip antenna to be tested is a GSG probe mode (i.e., a GSG feeding port), and the receiving antenna is a standard gain antenna fed by a waveguide. Since the impedance of the waveguide and the probe are not the same, the transmission mode of the electromagnetic wave is different, so it is impossible to calibrate directly. The present invention combines conventional TRL calibration by combining the ordinary calibration method of waveguide or coaxial and the TRL calibration method of the probe to calibrate the part of the test link other than the probe and the adapter cable first, and then prepares three sets of probes and the necessary adapters and link cables, and pairs them in pairs. The insertion loss parameters in each case of two groups can be obtained. The insertion loss parameters of each probe cable combination can be obtained by solving the equation group for each group of probe cable combinations, which solves the problem that the link cannot be calibrated when the GSG probe is fed, and to a certain extent makes the results of the chip antenna gain pattern test more accurate.
[0065] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process and related instructions of the system method described above can refer to the corresponding process in the system embodiment, and will not be repeated here.
[0066] The above is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.
Claims
1. A chip antenna single-path probe feeding calibration system, based on a chip antenna measurement and calibration device, the chip antenna measurement and calibration device includes a radio frequency signal subsystem, a chip antenna feeding platform and a three-dimensional scanning subsystem; the radio frequency signal subsystem includes a vector network analyzer, characterized in that: The system includes: an air-floating frame platform, a probe station, a stage, two probe seats, a microscope, and two spectrum expansion modules; The probe station is arranged on the air-floating frame platform; The stage and the two probe seats are arranged on the probe platform; the two probe seats are located on both sides of the stage; the stage is used to place a straight-through calibration sheet; the straight-through calibration sheet is provided with a GSG feeding port; The side of each probe seat close to the straight-through calibration sheet is used to place the probe; the probe is connected to the straight-through calibration sheet; the side of each probe seat away from the straight-through calibration sheet is used to place the spectrum expansion module; the spectrum expansion module placed on each probe seat is connected to the probe during the feed calibration; The microscope is arranged above the through calibration sheet; the microscope is used to locate the position of each probe; The probe seat is used to adjust its position according to the position of the probe so that the probe placed thereon is in good contact with the GSG feeding port of the through calibration plate for feeding; The vector network analyzer is connected to the two spectrum spreading modules; the vector network analyzer is used for obtaining S21 readings of two probes passing through each other during feed calibration, and then calculating the insertion loss of each probe.
2. A chip antenna single-path probe feed calibration system according to claim 1, characterized in that: When the displacement of each probe on the through calibration piece is greater than one quarter of the needle tip length, the two are in good contact.
3. A chip antenna single-path probe feed calibration system according to claim 1, characterized in that: When performing feed calibration, use the method of connecting three probes in pairs to obtain the insertion loss of a single probe.
4. A chip antenna single-path probe feed calibration system according to claim 3, characterized in that: Two-by-two probes through S 21 The relationship between the reading and the insertion loss of a single probe is: Where A1 is the S of the vector network analyzer when probe 1 and probe 2 are connected directly. 21 A2 is the S reading of the vector network analyzer when probe 1 and probe 3 are connected directly. 21 A3 is the S reading of the vector network analyzer when probe 2 and probe 3 are connected directly. 21 Read the following: T1 is the insertion loss of probe 1, T2 is the insertion loss of probe 2, and T3 is the insertion loss of probe 3.
5. A chip antenna single-path probe feed calibration system according to claim 4, characterized in that: Calculate the insertion loss of each probe as follows:
6. A chip antenna single-path probe feed calibration system according to claim 1, characterized in that: The microscope is mounted on a slide rail, and when the positions of the probes are positioned, the microscope is moved away from the through calibration sheet.
7. A chip antenna single-path probe feed calibration system according to claim 1, characterized in that: When performing feed calibration, the feed port of the chip antenna to be tested is the GSG probe feed port.
8. The chip antenna single-path probe feed calibration system according to claim 1, characterized in that: When performing feeding calibration, the feeding port of the receiving antenna in the chip antenna measurement and calibration device is a waveguide feeding port.
9. A chip antenna single-path probe feed calibration system according to claim 1, characterized in that: When performing feed calibration, first calibrate the equipment except the probe and adapter cable.
10. A chip antenna single-path probe feed calibration method, based on a chip antenna single-path probe feed calibration system according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: Step S1, open the vector network, adjust the frequency multiplication times and the transmission power, set the test frequency, adjust the intermediate frequency bandwidth, and calibrate the vector network and the spread spectrum module to the two waveguide calibration end faces; Step S2, after calibration, placing the through calibration piece on the stage, and using the microscope to locate the positions of the probe 1 and the probe 2, and then adjusting the probe seat so that each probe is in good contact with the through calibration piece; Step S3, obtaining the S of the vector network analyzer when the probe 1 and the probe 2 are directly connected 21 Read the value, recorded as A1; Step S4, replace the probe 2 with the probe 3, repeat the method of step S2, and obtain the S of the vector network analyzer when the probe 1 and the probe 3 are directly connected. 21 The reading is recorded as A2; Step S5, replacing the probe 1 with the probe 2, repeating the method of step S2, and obtaining the S of the vector network analyzer when the probe 2 and the probe 3 are directly connected. 21 Read the number, record it as A3; Step S6, combining A1 and A 12 , said A3, calculates the insertion loss of each probe.