Radio frequency signal jig for non-radio frequency test seat

Abstract

The utility model discloses a radio frequency signal jig for a non-radio frequency test seat, which is characterized in that a tunable coupling plate is correspondingly arranged on the surface of an upper cover of the jig and at the projection position of an onboard antenna, and the area of the tunable coupling plate is adjusted to be the same as the projection area of the onboard antenna. And the distance between the tunable coupling plate and the onboard antenna is adjusted to be within a set distance range, and the load impedance of the radio frequency link is adjusted to be close to an impedance point by 50 ohms, so that the frequency response characteristic of the radio frequency signal is changed, impedance matching is realized, the anti-interference capability of the onboard measurement radio frequency signal is improved, and the mismeasurement proportion of a radio frequency modulation index is reduced. Besides, the tunable coupling plate is also connected with the impedance matching circuit, the inductance value or capacitance value of a tuning element in the impedance matching circuit is adjusted, the matching tuning impedance is replaced to enable the tunable coupling plate to be coupled and parasitic, and the impedance track of the radio frequency signal jig is moved to a 50-ohm matching point, so that better impedance matching is realized, and the impedance matching precision is improved. And the test precision and efficiency are further improved.

Description

Technical Field

[0001] The utility model belongs to the field of wireless communication, and particularly relates to a radio frequency signal fixture for a radio frequency test socketless device. Background Art

[0002] In the wireless communication industry, in order to reduce costs and enhance the market competitiveness of products, the current technological trend has phased out independent FPC (Flexible Printed Circuit) or LDS (Laser Direct Structuring) process antenna components. Now, the antenna function is directly integrated into the printed circuit board (PCB) of the device, forming an on-board antenna design. Along with this change, the test method for the radio frequency (RF) main board has also evolved into a 1-to-8 scheme, aiming to further reduce production costs. However, this 1-to-8 RF production test scheme based on the on-board antenna design has exposed some problems. Since the on-board antenna is not equipped with a dedicated RF test socket, the conduction test of the radio frequency signal must be carried out through the antenna trace, adding antenna matching, resulting in inaccurate test impedance, and thus generating mismeasurement of radio frequency indicators. In addition, due to the too-close distance between antennas, the mutual interference problem is serious, making the mismeasurement rate increase significantly, so multiple retests are required to confirm the results. Content of the Utility Model

[0003] The utility model provides a radio frequency signal fixture for a radio frequency test socketless device, which reduces the mismeasurement ratio of radio frequency modulation indicators.

[0004] The utility model discloses a radio frequency signal fixture for a radio frequency test socketless device, including:

[0005] An upper fixture cover and a lower fixture cover, with an antenna accommodation area provided between the upper fixture cover and the lower fixture cover; an on-board antenna is integrated in the antenna accommodation area;

[0006] A tunable coupling plate, which is arranged on the surface of the upper fixture cover, at the projection position of the on-board antenna, and has a set distance from the on-board antenna;

[0007] The area of the tunable coupling plate is the same as the projected area of the on-board antenna.

[0008] Further, the set distance between the tunable coupling plate and the on-board antenna is 1 mm -

[0009] 2.4 mm.

[0010] Further, it further includes: an impedance matching circuit;

[0011] One end of the impedance matching circuit is connected to one end of the tunable coupling plate, and the other end is grounded.

[0012] Further, the impedance matching circuit includes: a first impedance tuning element, a second impedance tuning element, and a third impedance tuning element;

[0013] One end of the first impedance tuning element is respectively connected to one end of the second impedance tuning element and the tunable coupling plate, and the other end is connected to one end of the third impedance tuning element. The other end of the third impedance tuning element is grounded.

[0014] Further, the first impedance tuning element, the second impedance tuning element, and the third impedance tuning element are capacitors or inductors.

[0015] Further, an installation groove is formed between the upper fixture cover and the lower fixture cover.

[0016] Further, the tunable coupling plate is adhered to one surface of the installation groove.

[0017] Further, probe test points are also provided in the tunable coupling plate.

[0018] Further, a ground probe test point and a feed point probe test point are provided in the antenna accommodation area.

[0019] Further, the tunable coupling plate includes copper foil and aluminum foil.

[0020] Compared with the prior art, the radio frequency signal fixture without a radio frequency test socket disclosed by the present utility model has at least the following technical effects:

[0021] On the surface of the upper fixture cover, a tunable coupling plate is correspondingly arranged at the projection position of the board-mounted antenna. By adjusting the area of the tunable coupling plate to be the same as the projection area of the board-mounted antenna and adjusting the distance between the tunable coupling plate and the board-mounted antenna within a set distance range, the load impedance of the radio frequency link can be adjusted to be close to the impedance point of 50 ohms, thereby changing the frequency response characteristic of the radio frequency signal, achieving impedance matching, thereby improving the anti-interference ability of the board test radio frequency signal and reducing the mismeasurement ratio of the radio frequency modulation index. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic structural diagram of a radio frequency signal fixture for a radio frequency test socket-free in an embodiment of the present utility model;

[0023] Figure 2 is a positional relationship diagram between an antenna accommodation area and a tunable coupling plate in an embodiment of the present utility model;

[0024] Figure 3 is a positional relationship diagram of a tunable coupling plate in an embodiment of the present utility model;

[0025] Figure 4It is a comparison diagram of impedance matching effects before and after connecting an antenna in an embodiment of the present utility model;

[0026] Figure 5 It is a comparison diagram of impedance matching effects between a radio frequency signal fixture with a tunable coupling plate installed and a radio frequency signal fixture without a tunable coupling plate installed in an embodiment of the present utility model;

[0027] Figure 6 It is a schematic structural diagram of an impedance matching circuit in an embodiment of the present utility model. Specific embodiments

[0028] The following will describe a radio frequency signal fixture for a radio frequency test socketless in the present utility model with reference to schematic diagrams, in which the preferred embodiments of the present utility model are shown. It should be understood that those skilled in the art can modify the present utility model described herein while still achieving the advantageous effects of the present utility model. Therefore, the following description should be understood as a broad guidance for those skilled in the art and not as a limitation to the present utility model.

[0029] In the following paragraphs, the present utility model will be described more specifically by way of example with reference to the accompanying drawings. The advantages and features of the present utility model will be clearer according to the following description. It should be noted that the drawings are all in a very simplified form and use non-precise scales, only for the purpose of facilitating and clearly assisting in explaining the purpose of the embodiments of the present utility model.

[0030] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by terms such as "center", "longitudinal", "transverse", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the protection scope of the present utility model. The embodiments of the present utility model will be described in detail below with reference to the accompanying drawings.

[0031] Please refer to Figures 1 - 3 , this embodiment provides a radio frequency signal fixture for a radio frequency test socketless, including:

[0032] A fixture upper cover 1 and a fixture lower cover 4, with a board-mounted antenna 3 provided between the fixture upper cover 1 and the fixture lower cover 4; A tunable coupling plate 2, which is arranged on the surface of the fixture upper cover 1, at the projection position of the board-mounted antenna 3, and has a set distance from the board-mounted antenna 3; The area of the tunable coupling plate 2 is the same as the projected area of the board-mounted antenna 3.

[0033] In this embodiment, a tunable coupling plate 2 is correspondingly arranged at the projection position of the board-mounted antenna 3 on the surface of the fixture upper cover 1. The tunable coupling plate 2 is approximately an externally-mounted tunable series capacitor on the main board. Increasing the coupling area or reducing the spacing will increase the capacitance value, and the reactance will move a corresponding larger amount along the Smith equal susceptance circle. Therefore, by adjusting the area of the tunable coupling plate 2 to be the same as the projection area of the board-mounted antenna 3 and adjusting the distance between the tunable coupling plate 2 and the board-mounted antenna 3 within a set distance range, the load impedance of the RF link is adjusted to be close to the impedance point of 50 ohms, thereby changing the frequency response characteristics of the RF signal, achieving impedance matching, improving the anti-interference ability of the board-measured RF signal, and reducing the mismeasurement ratio of the RF modulation index.

[0034] In a specific embodiment, the tunable coupling plate 2 is a copper foil. In addition, the tunable coupling plate 2 can also be other metal materials with tunable impedance characteristics, such as: aluminum foil.

[0035] In this embodiment, if the distance between the tunable coupling plate 2 and the projection position of the board-mounted antenna 3 is too far, the coupling strength is too weak to effectively transmit signals; if the distance is too close, the coupling strength is too strong, which may cause signal reflection and distortion, affecting the test accuracy. Therefore, the set distance between the tunable coupling plate 2 and the board-mounted antenna 3 needs to be accurately set according to factors such as the characteristics of the board-mounted antenna 3, the size and shape of the tunable coupling plate 2, etc.

[0036] In a specific embodiment, the set distance between the tunable coupling plate 2 and the board-mounted antenna 3 is 1 mm - 2.4 mm.

[0037] Please refer to Figure 5 , the purple line is the conduction impedance diagram when the antenna is not connected, and the green line is the impedance curve diagram when antenna matching is added. Due to the addition of antenna matching, the measured impedance is inaccurate, resulting in mismeasurement of RF indicators. Therefore, compared with the marked points in the purple line, the marked points in the green line are farther from the center point of the Smith circle (i.e., the 50Ω RF matching point). Please refer to Figure 6 again. The green line is the impedance curve diagram when the tunable coupling plate 2 is not set but antenna matching is added, and the purple line is the impedance curve diagram when the tunable coupling plate 2 is set and antenna matching is added. As can be seen from the figure, when the tunable coupling plate 2 is added to the RF fixture, and the area of the tunable coupling plate 2 is adjusted to be the same as the projection area of the board-mounted antenna, and the set distance between it and the board-mounted antenna 3 is 1 mm - 2.4 mm, the marked points in the purple line are closer to the center point of the Smith circle, thereby improving the anti-interference ability of the board measurement and reducing the mismeasurement ratio of the RF modulation index.

[0038] Further, please refer to Table 1. Compared with the RF signal fixture without a tunable coupling plate, the RF signal fixture provided in this embodiment can significantly reduce the mismeasurement rate of the RF modulation index by at least 34.5%.

[0039] Table 1

[0040] Metal-free coupling plate solution Solution with metal coupling plate Total quantity 4523 4633 Number of mismeasurements 1572 11 Mismeasurement rate 34.76％ 0.24％

[0041] Further, in order to further improve the impedance matching of the RF signal fixture and improve the test accuracy and efficiency, an impedance matching circuit 5 is also provided in this embodiment.

[0042] Specifically, one end of the impedance matching circuit 5 is connected to one end of the tunable coupling plate 2, and the other end is grounded.

[0043] In a specific embodiment, the impedance matching circuit 5 includes: a first impedance tuning element A1, a second impedance tuning element A2, and a third impedance tuning element A3; a π-type impedance matching circuit is formed by the first impedance tuning element A1, the second impedance tuning element A2, and the third impedance tuning element A3.

[0044] Specifically, one end of the first impedance tuning element A1 is respectively connected to one end of the second impedance tuning element A2 and the tunable coupling plate, and the other end is connected to one end of the third impedance tuning element A3; the other end of the third impedance tuning element A3 is grounded.

[0045] In this embodiment, the first impedance tuning element A1, the second impedance tuning element A2, and the third impedance tuning element A3 are capacitors or inductors.

[0046] Please refer to Figure 6 , in this embodiment, by adjusting the inductance value or capacitance value of the tuning elements in the impedance matching circuit 5 and replacing the matching tuning impedance to make the tunable coupling plate 2 couple parasitically, the impedance trajectory of the RF signal fixture can be effectively moved to the 50-ohm matching point, thereby achieving better impedance matching and further improving the test accuracy and efficiency.

[0047] It can be understood that those skilled in the art can select capacitors with different capacitance values or inductors with different inductance values according to the impedance matching situation of the actual antenna, and adjust the impedance trajectory of the RF signal fixture to move to the 50-ohm matching point.

[0048] In this embodiment, the board-mounted antenna 3 is arranged in the antenna accommodation area.

[0049] Further, in this embodiment, the antenna accommodation area includes a small PCB board 9, a board-mounted antenna 3, and an impedance tuning small board 6. They are connected by means of metal traces, microstrip lines, or patch elements to form a complete RF signal transmission path.

[0050] Specifically, the small PCB board 9 serves as the carrier of the on-board antenna 3, on which metal traces and microstrip lines are etched for connecting the antenna elements and the impedance tuning small board 6. The impedance tuning small board 6 is used to adjust the impedance of the antenna. In this embodiment, the number of the small PCB board 9 and the on-board antenna 3 can be determined according to the actual situation and is not limited herein.

[0051] In a specific embodiment, the on-board antenna 3 includes 8 small PCB boards 9 and 8 on-board antennas 3.

[0052] Furthermore, location probe test points 8 and feed point probe test points 7 are also provided on the small PCB board 9.

[0053] Specifically, the location probe test points 8 and the feed point probe test points 7 are arranged at positions close to the on-board antenna 3 and are respectively arranged in one-to-one correspondence with the ground wire probe and the signal probe of the RF test fixture.

[0054] In this embodiment, the location probe test point 8 is used to connect the ground wire probe of the RF test fixture. During the test, by measuring the RF signal between the on-board antenna 3 and the ground wire, parameters such as the impedance and standing wave ratio of the antenna can be analyzed. The feed point probe test point 7 is used to connect the signal probe of the RF test fixture. During the test, by measuring the RF signal at the antenna feed point, parameters such as the input impedance and reflection coefficient of the on-board antenna 3 can be analyzed.

[0055] In this embodiment, both the tunable coupling board 2 and the impedance matching circuit 5 are arranged on the surface of the fixture upper cover 1.

[0056] Specifically, an installation groove 11 is formed between the fixture upper cover 1 and the fixture upper cover 2. The tunable coupling board 2 is pasted on the upper surface of the installation groove 11, and the antenna accommodation area is placed on the lower surface of the installation groove 11.

[0057] More specifically, the impedance matching circuit 5 is soldered on the external coupling circuit board.

[0058] In this embodiment, the number of the tunable coupling board 2 and the impedance matching circuit 5 is determined according to the number of the small PCB board 9 and the antenna, so that the fixture can perform independent impedance matching and testing on each antenna.

[0059] In a specific embodiment, there are 8 card slots. When the on-board antenna 3 includes 8 small PCB boards 9, 8 on-board antennas 3 and impedance tuning small boards 6 corresponding to the 8 on-board antennas 3, 8 tunable coupling boards 2 and 8 impedance matching circuits 5 are also arranged on the surface of the fixture upper cover 1 in one-to-one correspondence.

[0060] In addition, a probe test point 10 is also provided on the tunable coupling plate 2 for testing the coupling effect between the tunable coupling plate 2 and the on-board antenna 3. During the design and manufacturing process of the fixture, the probe test point 10 can be used to verify whether the connection between the tunable coupling plate 2 and the impedance matching circuit 5 is correct and whether the structure of the entire fixture is reasonable.

[0061] In this embodiment, the specific test steps for performing performance testing on the on-board antenna 3 using the RF signal fixture provided in this embodiment may include:

[0062] (1) Prepare the on-board antenna 3 to be tested and ensure that the position of the on-board antenna 3 corresponds to the position of the coupling copper foil of the fixture.

[0063] (2) Place the on-board antenna 3 between the fixture upper cover 1 and the fixture lower cover 4 and ensure a certain spacing is maintained between the coupling copper foil and the on-board antenna 3.

[0064] (3) Connect the fixture to the RF test equipment and ensure that the test equipment is in a normal operating state.

[0065] (4) Use the RF test equipment to measure the impedance between the coupling copper foil and the on-board antenna 3 and record the measurement results.

[0066] (5) According to the measurement results, adjust the length and connection method of the π-shaped matching circuit on the matching small board, change the impedance of the matching circuit, and make it match the impedance between the coupling copper foil and the on-board antenna 3.

[0067] (6) Repeat the measurement and adjustment until the best impedance matching effect is achieved.

[0068] (7) Use the RF test equipment to perform performance testing on the on-board antenna 3, such as measuring parameters such as its gain, directivity, and efficiency.

[0069] In summary, this embodiment is designed based on the principle of a series adjustable capacitor. By adjusting the area of the tunable coupling plate and its impedance offset from the on-board antenna 3, and adjusting the inductance value or capacitance value of the tuning element in the impedance matching circuit 5 to change the matching tuning impedance, the parasitic coupling of the tunable coupling plate is realized, so that the RF conduction impedance gradually approaches the ideal value of 50 ohms, enhancing the anti-interference ability during board testing.

[0070] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and its equivalent technologies, the present invention also intends to include these changes and modifications.

Claims

1. A radio frequency signal fixture for a radio frequency-free test socket, characterized in that Comprising: A fixture upper cover and a fixture lower cover, with an antenna accommodation area provided between the fixture upper cover and the fixture lower cover; The board-mounted antenna is integrated within the antenna accommodation area; A tunable coupling plate, which is disposed on the surface of the fixture upper cover, at the projection position of the board-mounted antenna, and has a set distance from the board-mounted antenna; The area of the tunable coupling plate is the same as the projected area of the board-mounted antenna.

2. The RF signal fixture for the RF-free test socket according to claim 1, wherein The set distance between the tunable coupling plate and the board-mounted antenna is 1 mm - 2.4 mm.

3. The RF signal fixture for the RF-free test socket according to claim 1, characterized in that, Further comprising: An impedance matching circuit; One end of the impedance matching circuit is connected to one end of the tunable coupling plate, and the other end is grounded.

4. The RF signal fixture for the RF-free test socket according to claim 3, wherein, The impedance matching circuit includes: a first impedance tuning element, a second impedance tuning element, and a third impedance tuning element; One end of the first impedance tuning element is respectively connected to one end of the second impedance tuning element and the tunable coupling plate, and the other end is connected to one end of the third impedance tuning element; the other end of the third impedance tuning element is grounded.

5. The RF signal fixture for the non-RF test socket according to claim 4, characterized in that, The first impedance tuning element, the second impedance tuning element, and the third impedance tuning element are capacitors or inductors.

6. The RF signal fixture for the RF-free test socket according to claim 3, wherein, An installation groove is formed between the surface of the fixture upper cover and the surface of the fixture lower cover.

7. The RF signal fixture for the non-RF test socket according to claim 6, wherein The tunable coupling plate is adhered to one surface of the installation groove.

8. The RF signal fixture for the RF-free test socket according to claim 1, wherein, Probe test points are further provided within the tunable coupling plate.

9. The RF signal fixture for the RF-free test socket according to claim 6, characterized in that, Ground probe test points and feed point probe test points are provided within the antenna accommodation area.

10. The RF signal fixture for the RF-free test socket according to claim 1, characterized in that, The tunable coupling plate includes copper foil and aluminum foil.

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