A high-frequency probe module with a semi-steel coaxial cable elastic needle tip and a test system

Abstract

This invention discloses a high-frequency probe module and testing system with a flexible tip on a semi-steel coaxial cable, relating to the field of circuit board testing technology. The probe module includes a probe module housing, a coaxial connector mounted on the housing, a semi-steel coaxial cable extending from the housing, and a flexible tip assembly at the cable's end. After stripping the outer shielding layer and insulating dielectric layer from the end of the semi-steel coaxial cable, the exposed inner conductor serves as a signal transfer point, while the outer shielding layer serves as a grounding transfer point. The signal pin is electrically connected to the inner conductor, and the grounding pin is electrically connected to the outer shielding layer. The high-frequency signal remains within the coaxial shielding structure from the coaxial connector to the tip soldering transfer position. This invention replaces the slender exposed portion of the PCB with a semi-steel coaxial cable, fundamentally avoiding warping and deformation problems. The signal path is coaxially shielded throughout, ensuring stable impedance and supporting high-frequency testing from 10GHz to 110GHz. Furthermore, the same module can simultaneously test bare boards and upper-mounted boards, resulting in a simplified structure, low cost, and high reliability.

Description

Technical Field

[0001] This invention relates to the field of circuit board testing technology, and more particularly to a scalable probe module for high-frequency and high-speed signal testing and a testing system including the probe module, belonging to the field of high-frequency and high-speed integrated circuit testing. Background Technology

[0002] With the rapid development of industries such as 5G millimeter-wave communication, high-speed artificial intelligence computing equipment, smart wearable radio frequency modules, automotive millimeter-wave radar, and advanced autonomous driving domain control, the application scale and performance requirements of high-frequency and high-speed circuit boards are increasing simultaneously. The demand for high-frequency signal integrity testing of PCBs continues to grow, and the test frequency band is gradually extending to GHz and even millimeter-wave bands, which puts forward more stringent requirements on the impedance stability, shielding performance, insertion loss and test adaptability of the test link.

[0003] Current mainstream circuit board testing solutions still have many technical bottlenecks and are difficult to adapt to the testing requirements of high-frequency scenarios. The core problems are concentrated in the following three points: 1. The performance limit of traditional flying probe testing solutions is insufficient. The core of flying probe testing is DC open and short circuit detection of circuit boards. Its probe structure, transmission mechanism and signal transmission link are designed for low-frequency continuity testing. Its inherent bandwidth is limited, and it cannot achieve accurate measurement of key signal integrity indicators such as S-parameters, characteristic impedance, insertion loss and crosstalk in the high-frequency band. It is difficult to meet the performance verification needs of current high-frequency and high-speed circuit boards.

[0004] 2. The solution of using onboard test slots with high-frequency flat cables consumes design resources. This solution requires reserving dedicated test slots on the circuit board under test and transferring test signals via high-frequency flat cables. This not only occupies valuable PCB routing space and reduces component layout margin, but also damages the impedance characteristics of the transmission lines on the board due to the structural discontinuity of the test slots. At the same time, high-frequency flat cables have problems such as short lifespan due to repeated bending, poor assembly consistency, and additional transmission loss, which further limits the test accuracy and applicability of the solution.

[0005] 3. The solution of using a slender exposed PCB to support a spring probe is structurally complex and lacks reliability. Existing technology uses a slender exposed PCB section extending from the probe module housing to mount the spring probe, relying on increasing the aspect ratio of the exposed structure to avoid tall components already soldered onto the board. However, this slender PCB structure is prone to warping due to stress release and changes in ambient temperature, leading to probe contact position misalignment, probe bending and damage, and at high frequencies, signal shielding failure and impedance fluctuations. To suppress warping and control dielectric loss, the solution requires additional complex structures including anti-warping components, heterogeneous reinforcing materials, adhesive layers, and insulating layers. This not only significantly increases material and assembly costs but also increases the difficulty of controlling processing tolerances, thus limiting product yield and long-term reliability. Summary of the Invention

[0006] The main objective of this invention is to enable high-frequency probes to bypass soldered components and test upper boards without using slender exposed PCB sections and their associated anti-warping components; to use a semi-steel coaxial cable as the entire coaxial shielded signal path from the probe module housing to the probe tip soldering adapter, and to directly test the PCB using standardized elastic probe tips; to reduce probe tip processing steps, avoid misalignment issues in three-pin precision soldering such as GSG, and improve production yield and assembly consistency; to provide stable contact force using the extension and retraction stroke of the elastic probe tip, tolerate uneven pads and skipped pins, and further reduce the risk of probe tip damage; to cover single-ended, coplanar waveguide, and differential testing scenarios through configurable contact combinations such as GSG, GS, GSSG, and SS; to test both bare boards and upper boards using the same probe module, reducing probe replacement time; to provide a high-frequency signal path with stable impedance, good shielding, and no warping issues for testing; and to simplify the structure, reduce costs, and facilitate manufacturing and assembly.

[0007] To achieve the above objectives, this invention provides a high-frequency probe module with a flexible tip on a semi-steel coaxial cable, comprising: a probe module housing structure, at least one coaxial connector disposed on the probe module housing, at least one semi-steel coaxial cable extending from the probe module housing, and a flexible tip assembly disposed at the end of the cable. The semi-steel coaxial cable is composed of an inner conductor, an insulating dielectric layer, and an outer shielding layer arranged sequentially from the inside out. The end of the semi-steel coaxial cable is stripped, removing a predetermined length of the outer shielding layer and the insulating dielectric layer, exposing the inner conductor to form a signal transfer point, while the remaining outer shielding layer forms a grounding transfer point. The flexible tip assembly includes a flexible tip, wherein the flexible tip includes at least one signal pin and at least one grounding pin; the signal pin is electrically connected to the inner conductor at the signal transfer point, and the grounding pin is electrically connected to the outer shielding layer at the grounding transfer point. In the high-frequency signal transmission path, from the coaxial connector to the pin tip soldering transfer position of the flexible tip assembly, the entire transmission path is enclosed by the coaxial shielding structure, no longer passing through the slender exposed portion of the PCB.

[0008] Furthermore, the elastic pin tip assembly can be configured as one of the following contact combinations according to the pad under test: GSG, GS, GSSG, or SS; wherein GSG is a signal pin in the middle between two ground pins, GS is a single ground pin with a single signal pin, GSSG is two signal pins sandwiched between two ground pins, and SS is two signal pins; each elastic pin tip can extend and retract in a direction perpendicular to the surface of the pad under test of the circuit board to adapt to the situation of the pad under test on various PCBs and meet the needs of different testing scenarios.

[0009] Furthermore, the characteristic impedance of the semi-steel coaxial cable is 50Ω, and the inner conductor is made of beryllium copper or tungsten wire. The length of the semi-steel coaxial cable extending from the probe module housing is greater than the height between the upper surface of the electronic component to be avoided on the circuit board and the upper surface of the circuit board. The semi-steel coaxial cable is pre-formed into an arc or Z-shaped three-dimensional curved shape to bypass the soldered electronic components.

[0010] Furthermore, the signal pin and the inner conductor, and the grounding pin and the outer shielding layer are fixed by laser welding to ensure connection reliability and signal transmission consistency.

[0011] Furthermore, an elastic needle tip insulator is provided at the position where the elastic needle tip protrudes from the end of the semi-steel coaxial cable. The elastic needle tip insulator fills the gap between the outer shielding layer and the elastic needle tip. This insulator enables the impedance of the transition area to smoothly transition to 50Ω, ensuring impedance matching for high-frequency signal transmission. At the same time, it can prevent short circuits between the outer shielding layer and the metal part of the circuit board under test when the needle tip is pressed down too far.

[0012] Furthermore, the probe module housing is provided with a coaxial connector and a semi-steel coaxial cable. The end of the semi-steel coaxial cable is equipped with a GSG or GS elastic tip assembly. The middle of the semi-steel coaxial cable is pre-bent into an arc or Z-shape, which is suitable for single-ended signal testing scenarios.

[0013] Furthermore, the probe module housing is provided with two coaxial connectors and two semi-steel coaxial cables. The two semi-steel coaxial cables are connected to the same set of GSSG or SS elastic tip assembly to form a differential test structure, which is suitable for differential signal testing scenarios.

[0014] Furthermore, the outer surface of the semi-steel coaxial cable is provided with a wave-absorbing tube or an insulating sheath to avoid short circuits and electromagnetic interference with adjacent components or metal structures; the welding transition point of the elastic needle tip and the outer shielding layer surface near the needle tip assembly are provided with a gold-plated layer to improve conductivity and oxidation resistance under high-frequency skin effect.

[0015] Optionally, a reinforcing rib can be laser-welded to the exposed section of the semi-steel coaxial cable extending out of the probe module housing to improve the structural strength of the cable extension section.

[0016] The present invention also provides a testing system, including a testing instrument, a coaxial cable, and a high-frequency probe module as described in any of the above. The testing instrument is connected to the coaxial connector of the high-frequency probe module via the coaxial cable, and can perform high-frequency signal excitation and acquisition on bare boards or upper boards. Furthermore, loss testing and impedance testing can be performed on an automated probe station.

[0017] This invention also provides a testing method for a high-frequency probe module, using any of the high-frequency probe modules described above, comprising the following steps: S1, moving the elastic tip of the high-frequency probe module above the pads of the circuit board under test; S2, driving the probe module to press down, the elastic tip adapting to the height difference of the pads by its own extension and retraction stroke, so that each tip contacts the corresponding pad under test; S3, controlling the testing instrument to output a high-frequency excitation signal, applying it to the pad under test via the high-frequency probe module, and acquiring the corresponding test signal; S4, processing the acquired signal to obtain S-parameters or other test data; the same module does not require probe replacement when changing the type of the board under test.

[0018] Compared with the prior art, the present invention has the following beneficial effects: (1) No need for slender PCB exposed parts and anti-warping components, adhesive layers, insulation layers and other supporting structures; when the cable extends a long distance, laser-welded reinforcing ribs can be added to improve the structural strength, thereby avoiding the problem of misalignment and bending damage caused by PCB warping from the source.

[0019] (2) The semi-steel coaxial cable itself has a complete shielding structure. The high-frequency signal maintains coaxial shielding transmission from the coaxial connector to the pin tip soldering transition position, which has strong anti-interference ability, stable impedance, and can stably support high-frequency testing of 10GHz-110GHz. It should be noted that the high-frequency bandwidth effect comes from the synergistic effect of the combined structure of "semi-steel coaxial cable directly connected to the elastic pin tip and eliminating the PCB cantilever" of this invention, and is not the inherent performance of the cable or the elastic pin tip alone.

[0020] (3) The elastic needle tip adopts a standardized telescopic structure, which eliminates the need for complex mold opening and chamfering, avoiding the offset problem of precision welding of GSG three needles, resulting in higher processing yield and assembly consistency; the needle tip is an independent consumable and can be replaced separately, resulting in low maintenance costs.

[0021] (4) The elastic tip absorbs the height difference of the pad by extending along the direction of the vertical pad, avoiding physical damage to the tip or probe assembly caused by hard contact or overtravel, thus improving the fault tolerance and probe life of the test.

[0022] (5) Multiple configurable contact combinations such as GSG, GS, GSSG, SS, etc., and one set of conversion process covers multiple test scenarios such as single-ended and differential, reducing the number of probe types.

[0023] (6) The same probe module is compatible with bare board and upper board testing; the semi-steel coaxial cable can be bent in three dimensions to bypass the devices on the board; the overall structure is simple, with few parts, and the manufacturing and assembly costs are low. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 , 2 This is an overall schematic diagram provided for an embodiment of the present invention; Figure 3 A side view provided for an embodiment of the present invention; Figure 4 A front view provided for an embodiment of the present invention; Figure 5 This is a cross-sectional view of a semi-steel coaxial cable provided in an embodiment of the present invention; Figure 6 This is a schematic diagram of the elastic tip of the SS configuration probe module provided in an embodiment of the present invention; Figure 7 This is a schematic diagram of the elastic tip of the GS configuration probe module provided in an embodiment of the present invention; Figure 8 A schematic diagram of the elastic tip of the GSG configuration probe module provided in an embodiment of the present invention; Figure 9 A schematic diagram of the elastic tip of the GSSG configuration probe module provided in an embodiment of the present invention; Figure 10 This is a schematic diagram showing the perpendicular contact between the needle tip and the pad of the object under test, provided in an embodiment of the present invention. Figure 11 This is a schematic diagram of the probe module and the testing system provided in an embodiment of the present invention.

[0026] The following are the labeling elements in the figure: 1. Probe module housing; 11. Bottom of mounting slot; 12. Cover plate; 13. Housing positioning post; 2. Coaxial connector; 3. Semi-steel coaxial cable; 31. Inner conductor; 32. Insulating dielectric layer; 33. Outer shielding layer; 34. Flexible needle tip insulator; 35. Laser welding point between flexible needle tip and inner conductor of semi-steel cable; 4. Laser welding point of outer shielding layer; 5. Flexible needle tip; 6. Grounding needle; 7. Signal needle.

[0027] The accompanying drawings have illustrated specific embodiments of the invention, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0029] To make the technical solutions and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0030] Please see Figures 1 to 11 This invention provides a high-frequency probe module with a flexible tip for a semi-steel coaxial cable. The probe module mainly includes a probe module housing 1, a coaxial connector 2 mounted on the probe module housing 1, a semi-steel coaxial cable 3 extending from the probe module housing 1, and a flexible tip 5 at the end of the semi-steel coaxial cable 3. The bottom of the probe module housing 1 has a mounting groove bottom surface 11, within which the semi-steel coaxial cable 3 is partially accommodated. The probe module housing 1 is provided with housing positioning posts 13, and a cover plate 12 is mounted on the probe module housing 1 via the housing positioning posts 13, thus covering and fixing the coaxial connector 2 and the semi-steel coaxial cable 3 within the mounting groove. This ensures that the components maintain a relatively stable positional relationship during testing, preventing signal transmission path deviation due to vibration or external force.

[0031] like Figure 5 As shown, the semi-steel coaxial cable 3 has an inner conductor 31, an insulating dielectric layer 32, and an outer shielding layer 33. The cable's characteristic impedance is 50Ω. The inner conductor 31 is preferably made of beryllium copper or tungsten wire to ensure good conductivity and mechanical strength. At the cable end, the outer shielding layer 33 and the insulating dielectric layer 32 are neatly stripped using a high-precision stripping process, exposing the inner conductor 31 as a signal transfer point, while the retained outer shielding layer 33 serves as a grounding transfer point. The length of the semi-steel coaxial cable 3 extending from the probe module housing 1 can be customized according to actual testing requirements. This length is greater than the height between the upper surface of the electronic component and the upper surface of the circuit board, allowing the elastic probe tip 5 at the cable end to pass over the soldered electronic component and accurately contact the target pad or slot. The cable can be pre-formed into a three-dimensional curved shape such as an arc or a Z-shape to bypass the soldered electronic component, thereby enabling direct point testing of the upper board without using a slender exposed PCB portion and its matching anti-warping components. The outer surface of the semi-steel coaxial cable 3 can also be equipped with a wave-absorbing tube or an insulating sheath to avoid short circuits and electromagnetic interference with adjacent components or metal structures.

[0032] The flexible pin tip assembly includes a flexible pin tip 5, which contains a signal pin 7 and a grounding pin 6. The signal pin 7 is electrically connected to the inner conductor 31, and the grounding pin 6 is electrically connected to the outer shielding layer 33. The signal pin 7 and the inner conductor 31 are fixed together by laser welding, forming a laser welding point 35 between the flexible pin tip and the inner conductor of the semi-steel cable; the grounding pin 6 and the outer shielding layer 33 are also fixed together by laser welding, forming a laser welding point 4 on the outer shielding layer. Laser welding ensures connection reliability and signal transmission consistency, avoiding problems such as cold solder joints and misalignment that may occur with traditional welding. A flexible pin tip insulator 34 is provided at the end of the flexible pin tip 5 exposed on the semi-steel coaxial cable 3. This insulator fills the space between the outer shielding layer 33 and the flexible pin tip 5, allowing the impedance of the transition area to smoothly transition to 50Ω, ensuring impedance matching for high-frequency signal transmission, and effectively preventing short circuits caused by metal contact between the outer shielding layer 33 and the PCB pads when the flexible pin tip 5 is pressed down too far. To further improve conductivity and oxidation resistance under high-frequency skin effect, gold plating is applied to the transition point of the elastic needle tip 5 and part of the surface of the outer shielding layer 33.

[0033] The flexible tip 5 uses a standardized, retractable flexible tip (such as a spring probe), which is retractable along the vertical axis and relies on a spring to provide contact force. Depending on the requirements of the pad being tested, the flexible tip assembly can be configured as GSG, GS, GSSG, or SS contact combinations. Figures 6 to 9 As shown, in the GSG configuration, the middle signal pin 7 is arranged with two symmetrical ground pins 6 on the left and right, suitable for coplanar waveguide or symmetrical single-ended testing; in the GS configuration, a signal pin 7 and a ground pin 6 are arranged side by side, suitable for single-ended signal testing with a single ground terminal; in the GSSG configuration, two ground pins 6 clamp two signal pins 7, suitable for differential or dual-signal testing; in the SS configuration, two signal pins 7 are arranged side by side, suitable for differential or paired signal testing without a local ground plane. Each pin tip is a standardized, retractable, elastic tip, adaptable to different conditions of the pads under test on various PCBs.

[0034] In one embodiment, the probe module housing 1 is provided with a coaxial connector 2 and a semi-steel coaxial cable 3. The cable end is equipped with a GSG or GS elastic tip assembly, and the middle of the cable is pre-bent into an arc or Z-shape, suitable for single-ended signal testing. In another embodiment, the probe module housing 1 is provided with two coaxial connectors 2 and two semi-steel coaxial cables 3. The ends of the two cables are equipped with GSSG or SS elastic tip assemblies to achieve differential testing, suitable for differential signal testing scenarios. When a longer extension is required, reinforcing ribs can be added to the exposed semi-steel coaxial cable 3 by laser welding to enhance the strength of the extended section.

[0035] During assembly, a specific length of semi-steel coaxial cable 3 is first taken, and a high-precision wire stripper is used to neatly strip the outer shielding layer 33 and the insulating dielectric layer 32 from the cable end, exposing the inner conductor 31. The length L of the cable extending beyond the bottom surface 11 of the probe module housing is reserved according to product requirements. Simultaneously, a custom fixture is used to process the laser welding points between the inner conductor 31 and the elastic needle tip 5. After completing the laser welding of a single elastic needle tip 5, another cable (if it is a dual-channel configuration) is processed in the same way, and then the processed cables are assembled using the coaxial connector 2. The assembled cable is placed in a custom fixing fixture, and laser welding is used to complete the welding of the outer shielding layer 33 extending beyond the housing length, forming the outer shielding layer laser welding point 4. Finally, the laser-welded cable assembly is placed into the mounting slot of the probe module housing 1.

[0036] To ensure the alignment of signal pin 7 and grounding pin 6, and the equal distance from the inner sides of the left and right grounding pins to the signal pin, a custom-made fixture is used for positioning and connection. The prepared semi-steel coaxial cable 3 is placed into the probe welding fixture, and the elastic pin tip assembly is placed into the positioning slot. After the fixture ensures precise alignment of each pin tip, laser welding is performed on the contact surfaces of the signal pin 7 and the inner conductor 31, and the contact surfaces of the grounding pin 6 and the outer shielding layer 33. After welding, the pin tip consistency and pin tip spacing are checked, and an open-circuit measurement is performed using a vector network analyzer to verify the impedance matching effect. Finally, the cover plate 12 is installed on the probe module housing 1 via the housing positioning post 13, securing the coaxial connector 2 and the semi-steel coaxial cable 3.

[0037] like Figure 10 , Figure 11 As shown, during actual testing, the elastic tip 5 of the probe module is perpendicularly contacted with the pad under test. The extension and retraction of the tip absorbs the height difference between the pads, ensuring that all tips make contact with the same plane before performing high-frequency testing. The testing instrument uses a coaxial cable, coaxial connector 2, semi-steel coaxial cable 3, and elastic tip 5 to excite and acquire high-frequency signals from the bare board or the mounting board, recording S-parameters or test data. The same module can simultaneously meet the testing requirements of both bare boards and mounting boards without requiring probe replacement when changing the type of board under test.

[0038] This invention also provides a test system and corresponding test method comprising the aforementioned probe module. The test system mainly includes test instruments (such as a vector network analyzer, time-domain reflectometer, or high-frequency signal generator and receiver) and a high-frequency probe module with a flexible tip on a semi-steel coaxial cable, configured as described above. When setting up the test system, the RF output port of the test instrument is connected to the coaxial connector 2 on the probe module housing 1 via a high-performance coaxial cable, thereby establishing a signal transmission link from the test instrument to the inside of the probe module. During testing, the high-frequency excitation signal generated by the test instrument is transmitted to the coaxial connector 2 via the coaxial cable, and then enters the semi-steel coaxial cable 3. Since the inner conductor 31, insulating dielectric layer 32, and outer shielding layer 33 of the semi-steel coaxial cable 3 constitute a complete coaxial transmission structure, the high-frequency signal is in a coaxial shielded environment throughout its journey from the coaxial connector 2 to the tip soldering transition position, effectively resisting external electromagnetic interference and reducing signal radiation loss. The signal continues to travel along the inner conductor 31 to the end, entering the signal pin 7 through the elastic needle tip and the laser welding point 35 of the inner conductor of the semi-steel cable. The grounding loop connects to the grounding pin 6 via the outer shielding layer 33 and the laser welding point 4 of the outer shielding layer. When the elastic needle tip 5 presses against the signal pads and ground pads of the printed circuit board under test, the test instrument can excite and acquire high-frequency signals from the bare board or the upper board. The entire test system can be further integrated into an automated probe station. The probe station's motion platform drives the probe module to move according to preset coordinates, realizing automatic alignment and batch testing of different test points on the circuit board, thereby efficiently completing the automated measurement of high-frequency signal integrity indicators such as insertion loss, return loss, characteristic impedance, and crosstalk.

[0039] When using the above testing system for actual testing, the following steps can be followed: Before starting the test, select a probe module with the corresponding contact combination (such as GSG, GS, GSSG, or SS) according to the pad layout and signal type on the printed circuit board under test, and install it on an automated probe station or a manual fine-tuning stand. Then move the probe module above the area to be tested, so that the elastic tip 5 is vertically aligned with the center of the pad under test. Next, control the probe module to slowly descend vertically, so that the signal pin 7 and the ground pin 6 simultaneously contact the corresponding pad surface. During the downward pressure, the elastic tip 5 automatically absorbs the coplanarity deviation between the pads caused by surface unevenness, plating thickness differences, or height differences of soldered components by the extension and contraction stroke of the built-in spring, until all tips are flat and stably pressed onto their respective pads. Because the elastic needle tip 5 is provided with an elastic needle tip insulator 34 at the end of the semi-steel coaxial cable 3, and the insulator effectively fills the gap between the outer shielding layer 33 and the needle tip, even if the elastic needle tip 5 has a large downward stroke, it can reliably prevent the outer shielding layer 33 from directly contacting the solder pad or other metal parts, thus eliminating the risk of short circuit.

[0040] After confirming stable contact of each probe tip, the testing instrument is started. A preset high-frequency excitation signal is sent to the pad under test via the probe module, and reflected and transmitted signals are simultaneously acquired. After internal processing by the testing instrument, key test data such as S-parameters, frequency domain impedance curves, or time domain reflection waveforms of the test point are obtained. After one test is completed, the probe module is vertically lifted, and the elastic probe tip 5 automatically extends and resets under the spring's restoring force. At this point, the probe module can be moved to the next test point, and the above steps can be repeated.

[0041] Throughout the testing process, because the semi-steel coaxial cable 3 is pre-formed into a three-dimensional curved shape such as an arc or a zigzag according to the actual distribution of components on the board under test, and its length L extending from the probe module housing 1 is greater than the height from the top surface of the electronic component to the top surface of the circuit board, the probe module can easily cross the component area and accurately contact the target pad or slot without touching any soldered components. When switching between different types of boards under test (such as bare boards without soldered components and boards with fully soldered components) using the same probe module, there is no need to change probes or recalibrate; only the test coordinates need to be adjusted for continuous operation, which greatly saves test preparation time and probe replacement costs.

[0042] When strong electromagnetic interference exists in the testing environment, or when the semi-steel coaxial cable 3 is too close to adjacent metal structures, an absorbing tube or insulating sheath can be fitted onto the outer surface of the semi-steel coaxial cable 3 to further absorb stray radiation and prevent accidental short circuits, ensuring the accuracy and repeatability of test data. For scenarios requiring long-term high-frequency use, since the flexible tip 5 is a standardized, replaceable consumable component, when the tip wears out, simply loosening the laser solder joint and replacing it with a new flexible tip assembly can quickly restore the test performance of the probe module, without scrapping the entire cable assembly, resulting in lower maintenance costs. Through the above steps, this invention can reliably and stably complete accurate testing of high-frequency, high-speed circuit boards (especially those containing millimeter-wave band signals) without the need for a slender exposed PCB portion and its matching anti-warping components. The test frequency band can stably cover 10GHz and has the capability to extend to 110GHz.

[0043] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the claims.

[0044] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intermediate element. Conversely, when an element is referred to as being "directly on" another element, there is no intermediate element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation. The terms "upper end," "lower end," "left side," "right side," "front end," "rear end," and similar expressions used herein refer to the positional relationship with reference to the accompanying drawings.

[0045] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is defined only by the appended claims.

Claims

1. A high-frequency probe module with a semi-steel coaxial cable elastic tip, characterized in that, include: Probe module housing (1); At least one coaxial connector (2) disposed on the probe module housing (1); At least one semi-steel coaxial cable (3) extending from the probe module housing (1), the semi-steel coaxial cable (3) being composed of an inner conductor (31), an insulating dielectric layer (32), and an outer shielding layer (33) in sequence from the inside to the outside; an elastic needle tip assembly disposed at the end of the semi-steel coaxial cable (3); The end of the semi-steel coaxial cable (3) is stripped to remove the outer shielding layer (33) and the insulating dielectric layer (32) of a preset length, so that the inner conductor (31) is exposed to form a signal transfer point, and the outer shielding layer (33) that is not stripped forms a grounding transfer point. The elastic needle tip assembly includes an elastic needle tip (5), the elastic needle tip (5) includes a signal needle (7) and a grounding needle (6), the signal needle (7) is electrically connected to the inner conductor (31) at a signal transition point, and the grounding needle (6) is electrically connected to the outer shielding layer (33) at a grounding transition point; On the high-frequency signal transmission path, from the coaxial connector (2) to the pin tip welding transition position of the elastic pin tip assembly, the entire transmission path is wrapped by the coaxial shielding structure.

2. The high-frequency probe module with a semi-steel coaxial cable elastic tip according to claim 1, characterized in that, The elastic needle tip assembly is configured as one of the following contact combinations: GSG, GS, GSSG or SS; wherein GSG is a signal needle in the middle of two grounding pins, GS is a single grounding pin with a single signal needle, GSSG is two signal needles clamped between two grounding pins, and SS is two signal needles; the elastic needle tip (5) is retractable in a direction perpendicular to the surface of the pads of the circuit board to be tested.

3. The high-frequency probe module with a semi-steel coaxial cable elastic tip according to claim 1, characterized in that, The characteristic impedance of the semi-steel coaxial cable (3) is 50Ω, and the inner conductor (31) is made of beryllium copper or tungsten wire. The length of the semi-steel coaxial cable (3) extending from the probe module housing (1) is greater than the height between the upper surface of the electronic component to be avoided on the circuit board and the upper surface of the circuit board. The semi-steel coaxial cable (3) is pre-formed into a three-dimensional curved shape, either arc-shaped or Z-shaped.

4. The high-frequency probe module with a semi-steel coaxial cable elastic tip according to claim 1, characterized in that, The signal pin (7) is fixed to the inner conductor (31) by laser welding, and the grounding pin (6) is fixed to the outer shielding layer (33).

5. The high-frequency probe module with a semi-steel coaxial cable elastic tip according to claim 1, characterized in that, The elastic needle tip (5) is provided with an elastic needle tip insulator (34) at the position where it protrudes from the end of the semi-steel coaxial cable (3). The elastic needle tip insulator fills the gap between the outer shielding layer (33) and the elastic needle tip (5).

6. The high-frequency probe module with a semi-steel coaxial cable elastic tip according to claim 1, characterized in that, The probe module housing (1) is provided with a coaxial connector (2) and a semi-steel coaxial cable (3). The end of the semi-steel coaxial cable (3) is equipped with a GSG or GS elastic needle tip assembly, and the middle part of the semi-steel coaxial cable (3) is pre-bent into an arc or a Z-shape.

7. The high-frequency probe module with a semi-steel coaxial cable elastic tip according to claim 1, characterized in that, The probe module housing (1) is provided with two coaxial connectors (2) and two semi-steel coaxial cables (3). The ends of the two semi-steel coaxial cables (3) are equipped with GSSG or SS elastic tip assemblies to realize differential testing.

8. The high-frequency probe module with a semi-steel coaxial cable elastic tip according to claim 1, characterized in that, The outer surface of the semi-steel coaxial cable (3) is provided with a wave-absorbing tube or an insulating sheath; the welding transition point of the elastic needle tip (5) and the surface of the outer shielding layer (33) near the needle tip assembly are provided with a gold-plated layer.

9. A testing system, characterized in that, The invention includes a testing instrument and a high-frequency probe module with a semi-steel coaxial cable elastic tip as described in any one of claims 1 to 8, wherein the testing instrument is connected to the coaxial connector (2) of the high-frequency probe module via the coaxial cable.

10. A testing method for a high-frequency probe module, characterized in that, A high-frequency probe module using a semi-steel coaxial cable elastic tip as described in any one of claims 1 to 8 includes the following steps: S1. Move the elastic tip (5) of the high-frequency probe module above the pads of the circuit board to be tested; S2, drive the probe module to press down, and the elastic needle tip (5) adapts to the height difference of the pad by its own extension stroke, so that each needle tip contacts the corresponding pad to be tested; S3. Control the test instrument to output a high-frequency excitation signal, apply it to the pad under test via the high-frequency probe module, and collect the corresponding test signal; S4. Process the acquired signal to obtain S-parameters or other test data.

Images