A needle tip structure for suppressing radiation, a two-dimensional probe and a microwave test system

Abstract

The application discloses a radiation-inhibiting needle tip structure, a two-dimensional probe and a microwave test system, and belongs to the technical field of microwave radio frequency test, and aims at the problems of radiation crosstalk aggravation, abnormal insertion loss and the fact that traditional three-dimensional probes are limited by process precision and are difficult to meet high-frequency test requirements in on-chip test of millimeter wave to terahertz band. The radiation-inhibiting needle tip structure comprises a ground wire and a signal wire, the ground wire is located on both sides of the signal wire to form a GSG needle tip structure, and a support structure is arranged between the ground wire and the signal wire; a cantilever type shielding layer is arranged above the ground wire, and a G needle root hollowing structure is formed in the position close to the needle tip root of the cantilever type shielding layer; the ground wire and the signal wire each comprise a lower nickel layer of the GSG needle tip structure and an upper copper layer of the GSG needle tip structure, a transition structure is arranged at the needle tip position of the ground wire, and the thickness of the transition structure gradually decreases from the needle tip root to the needle tip tip end; the signal wire is constrained to be transmitted in a quasi-TEM mode, and high-frequency radiation leakage is effectively inhibited; and the needle tip stress can be optimized by adjusting the structure parameters.

Description

Technical Field

[0001] This invention belongs to the field of microwave radio frequency testing technology, and particularly relates to a radiation-suppressing tip structure, a two-dimensional probe, and a microwave testing system. Background Technology

[0002] In high-frequency on-chip testing in the millimeter-wave to terahertz band (110 GHz to 1.1 THz), two major challenges are faced: First, when the operating frequency is higher than 110 GHz, especially above 200 GHz, the electromagnetic crosstalk of the probe tip is significantly aggravated, resulting in abnormally positive insertion loss after on-chip calibration (it is believed that a deviation ≥0.5 dB affects test accuracy, and ≥1 dB will cause failure error); Second, the traditional three-dimensional probe structure is limited by the minimum linewidth of the additive manufacturing process (typical value >50 to 100 μm), which cannot meet the processing accuracy required for the frequency band above 500 GHz, resulting in high-frequency impedance mismatch and signal integrity degradation.

[0003] Scholars and research teams have proposed a series of improvement schemes. For example, patent CN113960338A proposes a micro-coaxial RF probe based on multi-material additive manufacturing. By achieving efficient conversion between GSG tips (with three probes, the middle one being an S-type probe, and the two sides of the S-type probe being G-type probes, where G stands for Ground and S stands for Signal), rectangular micro-coaxial lines, and waveguides, it improves RF performance and processing flexibility. However, its tip mechanical properties are still limited, and the cost of a single probe is relatively high. Subsequently, patent CN115656580A proposed a copper-nickel composite additive manufacturing scheme based on this, introducing a 1 / 4 wavelength short-circuit stub support structure to improve the mechanical stability of the inner conductor, covering multiple bands including W, D, and G, and effectively reducing volume and cost. However, it mainly focuses on mechanical performance optimization and still has shortcomings in high-frequency radiation suppression and terahertz band expansion. Furthermore, patent CN117686753A proposes a micro-coaxial RF cantilever probe structure. By optimizing the cantilever beam design and chamfer structure of the G-pin and S-pin, it achieves consistency in needle mark depth. An anti-radiation structure is added to the needle tip to improve consistency, extending the applicable frequency band to 220GHz to 325GHz and 330GHz to 500GHz. However, the core of this solution still focuses on improving the mechanical properties and wear resistance of the needle tip; it does not provide a systematic solution for suppressing electromagnetic crosstalk in the terahertz frequency band.

[0004] In summary, existing probe structures have made some progress in terms of processing accuracy, mechanical stability, and partial radiation suppression, but they are still difficult to simultaneously meet the dual requirements of electromagnetic radiation control in the terahertz band and high-frequency testing adaptability. Summary of the Invention

[0005] To address the aforementioned problems and achieve the aforementioned objectives, this invention provides a radiation-suppressing tip structure and a two-dimensional probe solution, aiming to systematically solve the problems of high-frequency radiation crosstalk and terahertz frequency band compatibility.

[0006] To achieve the above objectives, in a first aspect, the present invention provides a radiation-suppressing needle tip structure, comprising a ground wire and a signal line, wherein the ground wire is located on both sides of the signal line to form a GSG needle tip structure, and a support structure is provided between the ground wire and the signal line; a cantilevered shielding layer is provided above the ground wire, and a G-needle root hollowing structure is formed in the cantilevered shielding layer near the root of the GSG needle tip structure; both the ground wire and the signal line include a lower nickel layer of the GSG needle tip structure and an upper copper layer of the GSG needle tip structure, and a transition structure is provided at the tip of the ground wire, wherein the thickness of the transition structure gradually decreases from the root of the GSG needle tip structure towards the tip.

[0007] As a further optimization, both the ground wire and the signal wire adopt a cantilever structure.

[0008] As a further optimization, the cantilevered shielding layer is located above the copper layer on the GSG tip structure.

[0009] As a further optimization, the transition structure includes a gradient structure of the lower nickel layer at the GSG tip, a gradient structure between the upper copper layer and the lower nickel layer, and a gradient structure of the upper copper layer at the GSG tip. The gradient structures of the lower nickel layer, the upper copper layer, and the upper copper layer at the GSG tip are all stepped structures.

[0010] As a further optimization, the thickness of the transition structure changes continuously from the root of the GSG needle structure to the tip of the GSG needle structure.

[0011] As a further optimization, at the hollowed-out structure at the root of the G-needle, the ground wire retains the nickel layer under the GSG needle tip structure.

[0012] Secondly, the present invention provides a two-dimensional probe structure, including a tip-to-rectangular coaxial line transition structure, an inner conductor of the rectangular coaxial line, an outer conductor of the rectangular coaxial line, a rectangular coaxial line-rectangular waveguide conversion structure, and the aforementioned tip structure for suppressing radiation; the inner conductor of the rectangular coaxial line is suspended in the outer conductor of the rectangular coaxial line through a support structure; a ground wire is connected to the outer conductor of the rectangular coaxial line, and a signal line is connected to the inner conductor of the rectangular coaxial line through the tip-to-rectangular coaxial line transition structure; the rectangular coaxial line-rectangular waveguide conversion structure includes a rectangular probe and an inner conductor protrusion structure; the rectangular probe is connected to the inner conductor of the rectangular coaxial line through the inner conductor protrusion structure; a waveguide cavity is formed in the outer conductor of the rectangular coaxial line; and the outer side of the rectangular probe is suspended in the waveguide cavity.

[0013] As a further optimization, the width of the transition structure from the tip to the rectangular coaxial line gradually increases from the connection point with the signal line towards the inner conductor of the rectangular coaxial line.

[0014] As a further optimization, the inner conductor of the rectangular coaxial line, the transition structure from the tip to the rectangular coaxial line, the rectangular probe, and the protruding structure of the inner conductor are all made of copper and nickel layers, with the copper layer located above the nickel layer.

[0015] Thirdly, the present invention also provides a probe structure, including a CNC machining fixture and the above-mentioned two-dimensional probe structure, wherein a probe mounting groove is formed at the bottom end of the CNC machining fixture, and a waveguide resonant cavity is formed on the probe mounting groove.

[0016] Fourthly, the present invention provides a microwave testing system, including the above-described two-dimensional probe structure or the probe structure described above.

[0017] Compared with existing technologies, this invention has at least the following advantages: This invention improves upon traditional millimeter-wave to terahertz frequency probes. Existing probes generally suffer from severe high-frequency radiation crosstalk, abnormal insertion loss, and limitations imposed by additive manufacturing precision bottlenecks, making it difficult to maintain stable impedance matching and signal integrity in frequency bands above 500 GHz. The radiation-suppressing tip structure proposed in this invention, by adding a cantilevered shielding layer to the ground wire, confines the signal line to quasi-TEM mode for transmission, effectively suppressing high-frequency radiation leakage. Simultaneously, by adjusting the structural parameters of the ground wire length and width... To optimize the stress characteristics of the needle tip, improve mechanical stability and reliability, and avoid deformation failure caused by stress concentration during testing, a hollowed-out structure is set at the root of the G-needle near the GSG needle tip structure in the cantilever shielding layer, retaining only the nickel layer at that location. This offsets the mechanical differences caused by the cantilever shielding layer, ensuring that the G-needle and S-needle are consistent under stress, thereby improving the consistency of needle mark depth during chip testing. A gradient design of copper and nickel layers is adopted in the radiation-suppressing needle tip structure to improve needle tip visibility, and the functional division of the upper copper layer and lower nickel layer improves the needle tip's wear resistance and electrical performance.

[0018] Furthermore, a support structure is introduced between the G-pin and S-pin of the GSG tip structure. The support structure is made of SU8 photoresist to enhance the force balance between the G-pin and S-pin, further improving the mechanical properties and structural stability of the tip, with minimal impact on the electrical performance of the device.

[0019] The two-dimensional probe proposed in this invention simplifies the overall structure and combines a CNC precision-machined metal fixture as an equivalent coaxial external conductor support, thus avoiding the limitations of the multi-layer stacking process in traditional additive manufacturing and breaking through the bottleneck of processing accuracy, enabling the probe to meet the testing requirements within 1.1THz.

[0020] Furthermore, the width of the transition structure from the needle tip to the rectangular coaxial line gradually increases from the needle tip towards the inner conductor of the rectangular coaxial line, thereby achieving impedance matching between the needle tip structure and the rectangular coaxial line.

[0021] Furthermore, the tip structure, the tip-to-rectangular coaxial line transition structure, the rectangular coaxial line, and the rectangular coaxial line-rectangular waveguide conversion structure are all composed of copper and nickel layers, which gives them good consistency in mechanical and electrical properties. Attached Figure Description

[0022] To more clearly illustrate the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments or the prior art will be briefly described below. It should be noted that the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0023] Figure 1 An oblique axonometric drawing of a radiation-suppressing needle tip structure based on additive manufacturing process provided in an embodiment of the present invention;

[0024] Figure 2 A front view of a radiation-suppressing needle tip structure based on additive manufacturing process provided in an embodiment of the present invention;

[0025] Figure 3 A schematic diagram of the reverse side of a radiation-suppressing needle tip structure based on additive manufacturing process provided in an embodiment of the present invention;

[0026] Figure 4 A schematic diagram of the lower nickel layer structure of a radiation-suppressing needle tip structure based on additive manufacturing process provided in an embodiment of the present invention;

[0027] Figure 5 A schematic diagram of the upper copper layer structure of a radiation-suppressing needle tip structure based on additive manufacturing process provided in an embodiment of the present invention;

[0028] Figure 6 An oblique axonometric view of a two-dimensional probe structure based on additive manufacturing process provided in an embodiment of the present invention;

[0029] Figure 7 A cross-sectional view of a microcoaxial transmission line of a two-dimensional probe structure based on additive manufacturing process provided in an embodiment of the present invention;

[0030] Figure 8 A schematic diagram of the transition structure from the tip to the rectangular coaxial line of a two-dimensional probe structure based on additive manufacturing process provided in an embodiment of the present invention is shown in Figure a. A schematic diagram of the partial markings of the transition structure from the tip to the rectangular coaxial line of a two-dimensional probe structure based on additive manufacturing process provided in an embodiment of the present invention is shown in Figure b. A magnified view of the partial details of the transition structure from the tip to the rectangular coaxial line is shown in Figure b.

[0031] Figure 9A schematic diagram showing the rectangular coaxial line-rectangular waveguide conversion structure and its local details in a two-dimensional probe structure based on additive manufacturing technology provided by an embodiment of the present invention; a is a schematic diagram showing the position of the rectangular coaxial line-rectangular waveguide conversion structure in a two-dimensional probe structure based on additive manufacturing technology provided by an embodiment of the present invention; b is a schematic diagram showing the local details of the rectangular coaxial line-rectangular waveguide conversion structure.

[0032] Figure 10 The images provided are an oblique axonometric view and a schematic diagram of the position of a two-dimensional probe structure integrated with a CNC fixture based on additive manufacturing process, provided in an embodiment of the present invention; a is an oblique axonometric view of a two-dimensional probe structure integrated with a CNC fixture based on additive manufacturing process, provided in an embodiment of the present invention; b is a schematic diagram of the position of the waveguide resonant cavity and the two-dimensional probe structure.

[0033] In the attached diagram: 1. Lower nickel layer of GSG tip structure; 2. Upper copper layer of GSG tip structure; 3. Hollowed-out structure at the root of the GSG needle; 4. Support structure; 5. Cantilever shielding layer; 6. Ground wire; 7. Gradient structure of the lower nickel layer at the tip of the GSG needle; 8. Gradient structure between the upper copper layer and the lower nickel layer; 9. Gradient structure of the upper copper layer at the tip of the GSG needle; 10. Tip structure for suppressing radiation; 11. Positioning hole; 12. Outer conductor of rectangular coaxial line; 13. Rectangular coaxial line to rectangular waveguide conversion structure; 14. Inner conductor of rectangular coaxial line; 15. Transition structure from needle tip to rectangular coaxial line; 16. Protruding inner conductor structure; 17. Rectangular probe; 18. Signal line; 19. CNC machining fixture; 20. Waveguide resonant cavity. Detailed Implementation

[0034] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. It should be noted that the described embodiments are merely some embodiments of this invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0035] In the description of the embodiments of the present invention, it should be understood that the terms "vertical", "horizontal", "vertical direction", "horizontal direction", "top", "bottom", "left side", "right side", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and should not be regarded as indicating that the indicated element or device is a specific orientation.

[0036] In the description of the embodiments of the present invention, the structural dimensions given are preferred parameters. Referring to the embodiments of the present invention, modifying the dimensional parameters of each component can further obtain the actual required performance.

[0037] This invention proposes a radiation-suppressing tip structure and a two-dimensional probe. Based on additive manufacturing, a cantilevered shielding layer 5 is added to the ground wire 6 of the tip structure, constraining the signal line 18 within the electromagnetic field cavity formed by the double-layer ground wire. This forces the signal to be transmitted in quasi-TEM mode, suppressing high-frequency radiation leakage. Simultaneously, by rationally adjusting the length and structure of the ground wire 6, not only can the electromagnetic field distribution characteristics be further improved, but the stress on the tip structure can also be optimized, enhancing mechanical stability and reliability, and avoiding deformation and failure caused by stress concentration during high-frequency testing. Furthermore, the two-dimensional probe body is simplified to a two-dimensional planar configuration (the signal line 18 and ground wire 6 are completed through additive manufacturing). Combined with a CNC precision-machined metal fixture, which serves as an equivalent rectangular coaxial line outer conductor 12 or a microstrip line ground plane, this avoids the limitations of multi-layer stacking processes in additive manufacturing, overcomes the bottleneck of processing accuracy, and allows the operating frequency to be extended to 1.1 THz. These two innovations, through structural reconstruction and process decoupling, systematically solve the problems of high-frequency radiation crosstalk and terahertz band compatibility.

[0038] This invention proposes a radiation-suppressing tip structure and a two-dimensional probe. Through structural reconstruction and process decoupling, it systematically solves the problems of high-frequency radiation crosstalk and terahertz frequency band adaptation. The two-dimensional probe includes a radiation-suppressing tip structure 10, a tip-to-rectangular coaxial line transition structure 15, an outer conductor 12 of the rectangular coaxial line, an inner conductor 14 of the rectangular coaxial line, and a rectangular coaxial line-rectangular waveguide conversion structure 13. Based on the radiation-suppressing tip structure 10, the signal line 18 can be constrained within an electromagnetic field cavity formed by a double-layer ground wire, forcing the signal to be transmitted in a quasi-TEM mode, suppressing high-frequency radiation leakage. Simultaneously, it optimizes the stress structure of the tip, enhancing mechanical stability and reliability, and avoiding deformation and failure caused by stress concentration during high-frequency testing. Furthermore, this solution circumvents the limitations of multi-layer stacking processes in additive manufacturing, overcomes the bottleneck of processing accuracy, and allows the operating frequency to be extended to 1.1 THz.

[0039] Example 1

[0040] This invention provides a radiation-suppressing needle tip structure based on additive manufacturing, comprising a ground wire 6 and a signal line 18. The ground wires 6 are located on both sides of the signal line 18, forming a GSG needle tip structure. The two ground wires 6 are symmetrical about the signal line 18. A support structure 4 passes through the signal line 18, with the two ends of the support structure 4 embedded with the two ground wires 6. The signal line 18 is suspended between the two ground wires 6 through the support structure 4. Both the signal line 18 and the ground wires 6 include a lower nickel layer 1 and an upper copper layer 2 of the GSG needle tip structure. The lower nickel layer 1 of the GSG needle tip structure includes a gradient structure 7 of the lower nickel layer at the tip of the GSG needle tip. The upper copper layer 2 of the GSG needle tip structure includes a hollowed-out structure 3 at the root of the needle, a cantilevered shielding layer 5, and a gradient structure 9 of the upper copper layer at the tip of the GSG needle tip. A gradient structure 8 between the upper copper layer and the lower nickel layer 1 of the GSG needle tip structure is provided. The indentation length d1 of the gradient structure 7 of the nickel layer under the GSG tip and the gradient structure 8 between the upper copper layer and the lower nickel layer is 25-30 μm, and the indentation length d2 of the gradient structure 9 of the upper copper layer under the GSG tip is 40-50 μm. These features are used to increase the visibility of the tip under a vertical microscope during probe detection. The nickel layer 1 under the GSG tip structure is the part where the probe tip contacts the device under test (DUT). Increasing the thickness of the nickel layer 1 under the GSG tip structure can improve the probe's wear resistance and strength. The cantilevered shielding layer 5 can confine the signal line 18 within the electromagnetic field cavity formed by the double-layer ground wire, forcing the signal to be transmitted in quasi-TEM mode and suppressing high-frequency radiation leakage.

[0041] In the GSG tip structure described in this invention, ground line 6 is a G-pin and signal line 18 is an S-pin. The thickness of the nickel layer 1 under the GSG tip structure is 50 μm, and the thickness of the copper layer 2 on the GSG tip structure is 150 μm.

[0042] The support structure 4 uses SU8 photoresist material with a relative permittivity of 3 and a loss tangent of 0.045. It is used to support the ground wire 6, the inner conductor 14 of the rectangular coaxial line, and the transition structure 15 from the tip to the rectangular coaxial line.

[0043] Example 2

[0044] The present invention provides a two-dimensional probe comprising a radiation-suppressing tip structure 10 as described in Embodiment 1 above, a tip-to-rectangular coaxial line transition structure 15, a rectangular coaxial line outer conductor 12, a rectangular coaxial line inner conductor 14, a rectangular coaxial line-rectangular waveguide conversion structure 13, and a support structure 4. The support structure 4 passes through the rectangular coaxial line inner conductor 14, and the two end support structures 4 are embedded in the rectangular coaxial line outer conductor 12. The rectangular coaxial line inner conductor 14 is suspended within the rectangular coaxial line outer conductor 12 through the support structure 4, forming a rectangular coaxial line structure. The length of the radiation-suppressing tip structure 10 to the tip-to-rectangular coaxial line transition structure 15 determines the matching quality between the radiation-suppressing tip structure 10 and the rectangular coaxial line structure. The optimized length of the tip-to-rectangular coaxial line transition structure 15 is between 150-180 μm. The rectangular coaxial line to rectangular waveguide conversion structure 13 includes an inner conductor protrusion structure 16 and a rectangular probe 17. The rectangular coaxial line to rectangular waveguide conversion structure 13 realizes the conversion from the rectangular coaxial line TEM mode to the rectangular waveguide model. After the parameters are optimized, the probe can achieve good matching with the external connecting waveguide.

[0045] Please see Figure 1 An oblique axonometric drawing of a radiation-suppressing needle tip structure based on additive manufacturing technology is provided in this embodiment of the invention. Figure 2 This is a front detail view of a radiation-suppressing needle tip structure based on additive manufacturing technology, provided in an embodiment of the present invention. Figure 3This is a schematic diagram of the reverse structure of a radiation-suppressing needle tip structure based on additive manufacturing process provided in an embodiment of the present invention. It includes a support structure 4 and two ground wires 6. A signal line 18 is set between the two ground wires 6. The two ground wires 6 are symmetrical about the signal line 18. The two ground wires 6 and the signal line 18 form a GSG needle tip structure. The signal line 18 is suspended between the two ground wires 6 through the support structure 4. The support structure 4 passes through the signal line 18. The two ends of the support structure 4 are embedded in the ground wires 6. The signal line 18 and the two ground wires 6 both include a lower nickel layer 1 and an upper copper layer 2 of the GSG needle tip structure. A gradient structure 8 between the upper copper layer and the lower nickel layer is set between the lower nickel layer 1 and the upper copper layer 2 of the GSG needle tip structure. Its indentation length is 25μm, which can increase the visibility of the needle tip under a vertical microscope when performing probe detection. The hollowed-out structure 3 at the root of the G-pin is used to offset the mechanical differences caused by the cantilever shielding layer, ensuring consistency between the G-pin and S-pin under stress, thereby improving the consistency of pin mark depth during chip testing. A cantilever shielding layer 5 is placed above the copper layer 2 on the GSG tip structure to constrain the signal line 18 within the electromagnetic field cavity formed by the double ground wire, forcing the signal to be transmitted in quasi-TEM mode and suppressing high-frequency radiation leakage. A support structure 4 is introduced between the G-pin and S-pin to enhance the stress balance between them, further improving the mechanical performance and structural stability of the tip. In use, the tip width t of the radiation-suppressing tip structure 10 determines the contact area between the probe tip and the device under test; after optimization, the tip width t is between 10-15 μm. This invention employs specific shape and size treatments in its structural design, achieving high efficiency in the conversion from coaxial mode to waveguide model, expanding the probe's operating frequency range, and improving adaptability in the millimeter-wave to terahertz frequency bands.

[0046] Without considering the difficulty of the process, the thickness of the transition structure described in this application can change continuously from the root of the GSG needle tip structure to the tip of the GSG needle tip structure. The curve of the continuous change can be a straight line, a convex curve, or a concave curve.

[0047] The inner conductor protrusion 16 has a size of 100-150 μm, and the rectangular probe 17 has a length of 250-350 μm and a width of 130-180 μm.

[0048] Please see Figure 4 This invention provides a schematic diagram of the nickel layer 1 under a GSG tip structure based on additive manufacturing to suppress radiation. The structure includes a support structure 4 embedded in the nickel layer 1 and a gradient structure 7 of the nickel layer under the GSG tip tip. The indentation length of the gradient structure 7 is 25 μm, which increases the visibility of the tip under a vertical microscope.

[0049] Please see Figure 5The present invention provides a schematic diagram of a GSG tip structure with copper layer 2 for suppressing radiation based on additive manufacturing process. The structure includes a hollowed-out structure 3 at the root of the G-needle, a cantilevered shielding layer 5, and a copper layer gradient structure 9 on the tip of the GSG tip. The copper layer gradient structure 9 on the tip of the GSG tip has a recessed length of 50 μm, which can increase the visibility of the tip under a microscope.

[0050] Please see Figure 6 This invention provides an isometric view of a two-dimensional probe structure based on additive manufacturing, comprising a radiation-suppressing tip structure 10, a tip-to-rectangular coaxial line transition structure 15, an outer conductor 12 of the rectangular coaxial line, an inner conductor 14 of the rectangular coaxial line, a rectangular coaxial line-rectangular waveguide conversion structure 13, and a positioning hole 11 for positioning the probe and fixture. The radiation-suppressing tip structure 10 confines the signal line 18 within an electromagnetic field cavity formed by a double-layer ground wire, forcing the signal to be transmitted in quasi-TEM mode, suppressing high-frequency radiation leakage. It also optimizes the stress structure of the tip, enhancing mechanical stability and reliability, and preventing deformation and failure due to stress concentration during high-frequency testing. The inner conductor 14 of the rectangular coaxial line is suspended within the outer conductor 12 of the rectangular coaxial line via a support structure 4. The rectangular coaxial line-rectangular waveguide conversion structure 13 is connected to an external rectangular waveguide to achieve a good match between the probe and the external connecting waveguide.

[0051] Please see Figure 7 This invention provides a cross-sectional view of a two-dimensional probe structure based on additive manufacturing, showing a micro-coaxial transmission line. The white portions L1, L2-U, and L3 are copper, and the black portions L2-L and L2-DS are nickel. The mechanical properties of the probe tip can be altered by changing the thickness of the nickel layer. When using this probe, the nickel layer 1 of the GSG probe structure repeatedly contacts the DUT (Device Under Test) of the chip.

[0052] Please see Figure 8 In this embodiment of the invention, a is a partial marked schematic diagram of the transition structure 15 from the tip to the rectangular coaxial line of a two-dimensional probe structure based on additive manufacturing process, and b is a magnified view of the partial details of the transition structure 15 from the tip to the rectangular coaxial line. The inner conductor of the transition structure 15 from the tip to the rectangular coaxial line is a rectangular structure with a gradually changing width along the axial direction. By changing the gradual length of the inner conductor, a good match is achieved between the radiation-suppressing tip structure 10 and the inner conductor 14 of the rectangular coaxial line.

[0053] Please see Figure 9In this embodiment, a is a schematic diagram of the position of the rectangular coaxial line-rectangular waveguide conversion structure 13 in a two-dimensional probe structure based on additive manufacturing technology provided by the present invention, and b is a magnified schematic diagram of a local detail of the rectangular coaxial line-rectangular waveguide conversion structure 13. The rectangular coaxial line-rectangular waveguide conversion structure 13 includes an inner conductor protrusion structure 16 and a rectangular probe 17. By optimizing the length and width of the inner conductor protrusion structure 16 and the rectangular probe 17, a good match between the two-dimensional probe and the external rectangular waveguide is achieved.

[0054] This invention proposes a radiation-suppressing tip structure and a two-dimensional probe: Based on additive manufacturing, a cantilevered shielding layer 5 is added to the probe's ground wire 6, constraining the signal line 18 within an electromagnetic field cavity formed by the double-layer ground wire. This forces the signal to be transmitted in quasi-TEM mode, suppressing high-frequency radiation leakage. Simultaneously, by rationally adjusting the length and other shape of the ground wire 6, not only can the electromagnetic field distribution characteristics be further improved, but the stress structure of the tip can also be optimized, enhancing mechanical stability and reliability, and avoiding deformation and failure caused by stress concentration during high-frequency testing. This radiation-suppressing tip structure 10 can be used in frequencies of 75 to 110 GHz, 110 to 170 GHz, 140 to 220 GHz, 170 to 260 GHz, 220 to 325 GHz, 330 to 500 GHz, and 500 to 1100 GHz.

[0055] Example 3

[0056] Please see Figure 10 In this diagram, a is an oblique axonometric view of a two-dimensional probe structure integrated with a CNC fixture based on additive manufacturing process provided in an embodiment of the present invention, and b is a schematic diagram of the positions of the waveguide resonant cavity 20 and the two-dimensional probe structure. The CNC machining fixture 19 includes an outer conductor and a waveguide resonant cavity 20. The depth parameter of the waveguide resonant cavity 20 determines the intrinsic resonance mode of the cavity. By optimizing the design of the depth of the waveguide resonant cavity 20, it is made to match the waveguide cutoff frequency and resonance conditions of the target operating frequency band, thereby ensuring that the probe output signal can be efficiently excited and achieve complete energy coupling within the required frequency range.

[0057] This invention also proposes a probe structure that employs a design strategy combining a two-dimensional planar configuration with a hybrid manufacturing process. Specifically, the conductive portion of the two-dimensional probe is integrally formed into a two-dimensional planar structure using additive manufacturing, achieving complex micron-level features. The outer conductor, which serves as shielding and grounding, and the waveguide resonant cavity 20 are precision-machined into an independent CNC machining fixture 19. A probe mounting slot is formed at the bottom of the CNC machining fixture 19, and the waveguide resonant cavity 20 is formed on the probe mounting slot. The waveguide resonant cavity 20 extends into the waveguide channel of the CNC machining fixture 19. The CNC machining fixture 19 not only provides mechanical support and positioning for the two-dimensional probe body, but also acts as an equivalent rectangular coaxial outer conductor, forming a complete transmission system together with the built-in signal body. This decoupled process design avoids the machining accuracy bottlenecks of traditional single additive manufacturing processes when vertically stacked, such as minimum linewidth limitations, insufficient sidewall steepness, and internal stress problems. It fully utilizes the advantages of CNC machining in ultra-high precision and excellent surface finish, thus successfully extending the upper limit of the probe's reliable operating frequency to 1.1THz while ensuring excellent high-frequency performance. This solution can be used for waveguide testing from 75 GHz to 110 GHz, 110 GHz to 170 GHz, 140 GHz to 220 GHz, 170 GHz to 260 GHz, 220 GHz to 325 GHz, 330 GHz to 500 GHz, and 500 GHz to 1100 GHz. Through innovations in both structural reconstruction and process decoupling, the problems of high-frequency radiated crosstalk and terahertz band adaptation are systematically solved.

[0058] The radiation-suppressing needle tip structure of this invention adopts the GSG form. The signal line 18 and the ground line 6 are cantilevered. A gradient structure is set between the nickel layer 1 under the GSG needle tip structure and the copper layer 2 on the GSG needle tip structure to improve visibility and wear resistance. The G needle is equipped with a cantilevered shielding layer to suppress radiation, and the difference in mechanical properties is offset by hollowing out the copper layer at the base end. A support structure 4 is set between the G needle and the S needle to enhance the consistency of force. The S needle is transitioned to the inner conductor 14 of the rectangular coaxial line through the needle tip to the rectangular coaxial line transition structure 15. The inner conductor 14 of the rectangular coaxial line is suspended in the outer conductor 12 of the rectangular coaxial line by the support structure 4. The inner conductor of the rectangular coaxial line to rectangular waveguide conversion structure 13 achieves broadband impedance matching through the inner conductor protrusion structure 16 and shape optimization, which can avoid the limitations of multi-layer stacking process, improve processing accuracy, support frequency extension to 1.1THz, and is suitable for Asia-Pacific Hertz and Terahertz testing and applications.

[0059] The above describes a solution for a radiation-suppressing tip structure and a two-dimensional probe based on additive manufacturing technology provided by the present invention. For those skilled in the art, based on the ideas of the embodiments of the present invention, there will be changes in specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A needle tip structure for suppressing radiation, characterized in that, It includes a ground wire (6) and a signal wire (18). The ground wire (6) forms a GSG needle tip structure on both sides of the signal wire (18). A support structure (4) is set between the ground wire (6) and the signal wire (18). A cantilever shielding layer (5) is set above the ground wire (6). A G-pin root hollowing structure (3) is opened near the root of the GSG needle tip structure in the cantilever shielding layer (5). Both the ground wire (6) and the signal wire (18) include a nickel layer (1) under the GSG needle tip structure and a copper layer (2) on the GSG needle tip structure. A transition structure is set at the tip of the ground wire (6). The thickness of the transition structure gradually decreases from the root of the GSG needle tip structure to the tip.

2. The needle tip structure for suppressing radiation according to claim 1, characterized in that, Both the ground wire (6) and the signal wire (18) adopt a cantilever structure.

3. The needle tip structure for suppressing radiation according to claim 1, characterized in that, The cantilever shielding layer (5) is located above the copper layer (2) on the GSG tip structure.

4. The needle tip structure for suppressing radiation according to claim 1, characterized in that, The transition structure includes a gradient structure of the nickel layer under the GSG tip (7), a gradient structure between the upper copper layer and the lower nickel layer (8), and a gradient structure of the upper copper layer at the GSG tip (9). The gradient structure of the nickel layer under the GSG tip (7), the gradient structure between the upper copper layer and the lower nickel layer (8), and the gradient structure of the upper copper layer at the GSG tip (9) are all stepped structures.

5. The needle tip structure for suppressing radiation according to claim 1, characterized in that, The thickness of the transition structure changes continuously from the root of the GSG needle structure to the tip of the GSG needle structure.

6. The needle tip structure for suppressing radiation according to claim 1, characterized in that, At the hollowed-out structure (3) at the root of the G needle, the ground wire (6) retains the nickel layer (1) under the GSG needle tip structure.

7. A two-dimensional probe structure, characterized in that, The system includes a tip-to-rectangular coaxial line transition structure (15), an inner conductor (14) of the rectangular coaxial line, an outer conductor (12) of the rectangular coaxial line, a rectangular coaxial line-rectangular waveguide conversion structure (13), and a tip structure (10) for suppressing radiation as described in any one of claims 1-6. The inner conductor (14) of the rectangular coaxial line is suspended in the outer conductor (12) of the rectangular coaxial line through a support structure (4). The ground wire (6) is connected to the outer conductor (12) of the rectangular coaxial line, and the signal line (18) is connected to the inner conductor (14) of the rectangular coaxial line through the tip-to-rectangular coaxial line transition structure (15). The rectangular coaxial line-rectangular waveguide conversion structure (13) includes a rectangular probe (17) and an inner conductor protrusion structure (16). The rectangular probe (17) is connected to the inner conductor (14) of the rectangular coaxial line through the inner conductor protrusion structure (16). The outer conductor (12) of the rectangular coaxial line has a waveguide cavity, and the outer side of the rectangular probe (17) is suspended in the waveguide cavity.

8. The two-dimensional probe structure according to claim 7, characterized in that, The width of the transition structure (15) from the tip to the rectangular coaxial line gradually increases from the connection point with the signal line (18) toward the inner conductor (14) of the rectangular coaxial line.

9. The two-dimensional probe structure according to claim 7, characterized in that, The inner conductor of the rectangular coaxial line (14), the transition structure from the tip to the rectangular coaxial line (15), the rectangular probe (17), and the protruding structure of the inner conductor (16) are all made of copper and nickel layers, with the copper layer located above the nickel layer.

10. A probe structure, characterized in that, The invention includes a CNC machining fixture (19) and a two-dimensional probe structure as described in any one of claims 7-9, wherein a probe mounting groove is provided at the bottom end of the CNC machining fixture (19), and a waveguide resonant cavity (20) is provided on the probe mounting groove.

11. A microwave testing system, characterized in that, Includes the two-dimensional probe structure as described in any one of claims 7-9 or the probe structure as described in claim 10.

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