A micro coaxial load structure with ultra-wideband performance and a millimeter-wave spread spectrum module

Abstract

The present invention discloses a micro coaxial load structure with ultra-wideband performance and a millimeter-wave spread-spectrum module, belonging to the technical field of microwave and millimeter-wave. The micro coaxial load structure includes a micro coaxial package structure and a quartz substrate. The quartz substrate is arranged on the micro coaxial package structure in an inverted manner and is electrically connected to the micro coaxial package structure. The quartz substrate includes a quartz sheet, metal pads, and a thin-film resistor. The metal pads and the thin-film resistor are located on the surface of the quartz sheet, and the thin-film resistor is located between the pads. The metal pads are used to connect the micro coaxial package structure, realizing the function of an ultra-wideband load. When the signal transmission direction is parallel to the plane where the pads are located, the operating frequency range is from DC to 150 GHz. When the signal transmission direction is perpendicular to the plane where the pads are located, the operating frequency is from DC to 130 GHz. The inverted quartz substrate helps to fix the relative positions of the inner conductor and the outer conductor, enhancing the mechanical stability of the overall structure.

Description

Technical Field

[0001] The present invention relates to the technical field of microwave and millimeter wave, and particularly relates to a micro coaxial load structure with ultra-wideband performance and a millimeter wave spread spectrum module. Background Art

[0002] In the microwave and millimeter wave frequency bands, restricted by transmission line structures such as waveguides and microstrip lines, and traditional processing technologies such as CNC and PCB, it is difficult to achieve all of the indicators of low loss, high density integration, and one-piece molding. In the process of the development of microwave and millimeter wave systems towards the goals of miniaturization, integration, and lightweight, the copper-based air micro coaxial technology has emerged. This technology adopts the idea of layer-by-layer processing, integrating a variety of microfabrication processes such as photolithography, electroplating, and chemical mechanical polishing, and can process high-precision air-filled micro coaxial structures.

[0003] The loss of the micro coaxial structure is similar to that of the waveguide structure, but the size is very compact, similar to that of the microstrip line. Therefore, the micro coaxial device has the characteristics of low loss and small volume. In addition, due to the quasi-closed structure of the micro coaxial transmission line and the TEM single-mode transmission characteristics, the micro coaxial device also has the advantages of high inter-line isolation, wide operating frequency band, and easy integration with active chips, and is very suitable for designing high-performance microwave and millimeter wave microsystems. For some multi-port devices (such as couplers) and microsystems (such as millimeter wave spread spectrum modules), the unused ports need to be connected to a load structure, which is usually connected to the end of the circuit, so it is also called a terminal load or a matching load.

[0004] Radio frequency coaxial loads are widely used in radio equipment, electronic instruments, and various types of equipment, and are mainly used for the testing of radio frequency signal transmission systems and the end connection of electronic equipment systems. In the system, the radio frequency coaxial load can perform impedance matching on the spare channels and test ports of the vacant equipment, so as to ensure the impedance matching of the signal, significantly reduce the signal leakage of the vacant ports and the mutual interference between systems. As an important part of the radio frequency transmission system, its performance directly affects the comprehensive performance of the entire system.

[0005] However, the existing radio frequency coaxial load structures mainly rely on external coaxial loads or waveguide loads. Although this design can meet the basic performance requirements, it significantly increases the packaging volume of the system and limits the advantages of the micro coaxial structure in high-integration and miniaturized systems. In addition, when such load structures achieve ultra-wideband performance, they often face problems of frequency band limitation and high power consumption.

[0006] The patent application with the publication number CN118589177A proposes a high-power microwave millimeter-wave load solution with an electromagnetic field constraint structure, which consists of an electromagnetic field constraint metal carrier, a high-power load, and gold wires. The concave electromagnetic field constraint metal carrier is used to improve the load performance and reduce the influence on the frequency response of high-power microwave circuits, focusing on solving the performance problems of high-power loads in the high-frequency band, such as the working frequency range, voltage standing wave ratio, and cost, and not focusing on the ultra-wideband performance and the design of related micro-coaxial structures.

[0007] The patent application with the publication number CN202749489U discloses a radio frequency coaxial load structure, which includes components such as an inner conductor, an outer conductor, a resistor, an insulator, and a rear cover. A sheet resistor is used to reduce the volume and improve the connection reliability. This patent mainly focuses on optimizing the structure of the coaxial load to achieve miniaturization and high-reliability connection, and the pursuit of ultra-wideband performance is not its concern, and in-depth research has not been carried out on the complex design of the micro-coaxial structure and ultra-wideband frequency coverage.

[0008] Therefore, developing a compact micro-coaxial load structure with ultra-wideband characteristics is crucial for promoting the further miniaturization and high integration of microwave millimeter-wave devices and microsystems. Such a structure not only needs to achieve excellent impedance matching performance in the ultra-wide frequency band range but also needs to take into account the feasibility of the processing technology and cost control to meet the actual application requirements. The breakthrough of this technology will provide a higher-performance and higher-reliability solution for the next-generation microwave millimeter-wave system, bringing far-reaching impacts on the development of fields such as wireless communication, radar detection, and precision instruments, and having important practical significance. Summary of the Invention

[0009] The main purpose of the present invention is a micro-coaxial load structure with relatively high mechanical strength, including a micro-coaxial package and a quartz substrate. The micro-coaxial package includes an inner conductor, an outer conductor, and a dielectric support bar. The quartz substrate includes a quartz sheet, a metal pad, and a thin-film resistor. The quartz substrate is inversely welded on the inner conductor and the outer conductor of the micro-coaxial package. The inversely placed quartz substrate helps to fix the relative positions of the inner conductor and the outer conductor, enhancing the mechanical stability of the overall structure.

[0010] To achieve the above purpose, the present invention provides a micro-coaxial load structure with ultra-wideband performance, including a micro-coaxial package structure and a quartz substrate. The quartz substrate is arranged on the micro-coaxial package structure in an inverted manner, and the quartz substrate is electrically connected to the micro-coaxial package structure. The quartz substrate includes a quartz sheet, a thin-film resistor, and a metal pad. The thin-film resistor and the metal pad are arranged on the surface of the quartz sheet, and the thin-film resistor is located between the metal pads. The metal pads are used to connect the micro-coaxial package structure.

[0011] Further, there are three metal pads. The middle metal pad is electrically connected to the inner conductor, and the metal pads on both sides are electrically connected to the outer conductor.

[0012] Further, the micro coaxial load structure is formed based on the metal additive manufacturing process. The thickness of each layer is 0.1 mm, and the total thickness is 0.8 mm; the thickness of the quartz substrate is 0.127 mm.

[0013] Further, the micro coaxial package structure includes an inner conductor, an outer conductor, and dielectric support bars. The port of the micro coaxial package structure is a rectangular cross-section coaxial interface; the inner conductor is suspended inside the outer conductor through a plurality of dielectric support bars, and a plurality of dielectric support bars are arranged at intervals along the length direction of the micro coaxial package structure.

[0014] Further, the micro coaxial package structure is formed by an eight-layer process. The fifth layer is divided into an upper layer and a lower layer. The dielectric support bars are located in the lower layer of the fifth layer. The lower wall of the outer conductor is located in the first layer, the upper wall of the outer conductor is located in the eighth layer, and the side walls of the outer conductor are located in the second to seventh layers. At the position where the quartz substrate is provided, the side walls of the outer conductor extend inward to form two pads at the upper layer of the fifth layer; the pads on the inner conductor are located on the sixth layer of the inner conductor.

[0015] Further, the inner conductor is provided with a transition structure. The transition structure includes two connected transmission lines. The inner conductor of the first transmission line is located in the fourth and fifth layers, the inner conductor of the second transmission line is located in the upper layer of the fifth layer, and a pad is formed on the inner conductor where the second transmission line is located on the sixth layer.

[0016] Further, the body width of the inner conductor w 2 = 0.12 mm, the width of the inner conductors of the two transmission lines w 3 = 0.135 mm, the length of the first transmission line is l 2 = 0.4 mm, the length of the second transmission line l 3 = 0.15 mm, the length of the pad l 4 = 0.135 mm, the width of the pad w 4 = 0.1 mm.

[0017] Furthermore, the micro coaxial package structure includes an inner conductor, an outer conductor, and a dielectric support bar. The inner conductor is disposed within the outer conductor through the dielectric support bar, and the dielectric support bar is arranged circumferentially around the inner conductor. The micro coaxial package structure is formed by an eight-layer process, and both the inner conductor and the outer conductor are located in the first to eighth layers. The port of the micro coaxial package structure is a circular coaxial interface. From the first layer to the eighth layer, the diameters of the outer conductor and the inner conductor gradually decrease. The quartz substrate is located on the outer surface of the eighth layer of the outer conductor and the inner conductor.

[0018] Furthermore, the diameter of the inner conductor in the first layer d 3 = 0.342 mm, and the diameter of the inner conductor in the eighth layer d 4 = 0.173 mm; the diameter of the outer conductor in the first layer d 1 = 0.8 mm, and the diameter of the outer conductor in the eighth layer d 2 = 0.4 mm.

[0019] The present invention also provides a millimeter-wave spread-spectrum module, which adopts the micro coaxial load structure with ultra-wideband performance as described above.

[0020] Compared with the prior art, the micro coaxial load structure provided by the present invention has at least the following beneficial effects: Through the innovative design of the inverted quartz substrate, the positions of the inner conductor and the outer conductor are effectively fixed, which not only significantly improves the mechanical stability, but also enhances the reliability and processing accuracy of the load structure. By improving the design of the port of the micro coaxial broadband load structure, it can be reliably integrated and interconnected with the peripheral circuit, making the micro coaxial broadband load structure easier to test, easier to integrate, with wide adaptability, and can be widely applied to various terminal load scenarios such as multi-port devices and millimeter-wave spread-spectrum modules.

[0021] Furthermore, three metal pads are provided. The middle metal pad is welded to the inner conductor, and the metal pads on both sides are welded to the outer conductor. The thin-film resistor is located between the pads and is used to absorb the electromagnetic energy of the terminal, acting as a load. The sheet resistance of the thin-film resistor is designed to be 50 Ω to achieve better impedance matching.

[0022] Furthermore, the micro coaxial load structure provided by the present invention is small in volume. The copper-based air micro coaxial technology is used to achieve a micron-level three-dimensional structure, with a maximum length of several millimeters and a height of only 0.8 mm. The layer thickness of 0.1 mm makes the chip structure more uniform in the vertical distribution, reducing the difficulty of the manufacturing process. The total thickness of 0.8 mm provides sufficient mechanical support while ensuring the miniaturization of the chip structure, ensuring good structural reliability of the micro coaxial package. The quartz thickness of 0.127 mm not only ensures the uniformity of the electric field distribution but also can maintain excellent dielectric properties in the high-frequency range, reducing the interference to signal propagation.

[0023] Furthermore, the inner conductor diameter of the first layer is d 3 = 0.342 mm, and the inner conductor diameter of the eighth layer is d 4 = 0.173 mm; the outer conductor diameter of the first layer is d 1 = 0.8 mm, and the outer conductor diameter of the eighth layer is d 2 = 0.4 mm. Its high integration makes the micro coaxial load structure have good compatibility with modern miniaturized systems.

[0024] Furthermore, the micro coaxial package structure includes an inner conductor, an outer conductor, and dielectric support bars. The port of the micro coaxial load structure is a rectangular cross-section coaxial interface; the inner conductor is suspended inside the outer conductor through multiple dielectric support bars, and multiple dielectric support bars are arranged at intervals along the length direction of the micro coaxial package structure; the signal transmission direction is parallel to the plane where the metal pads are located, and the operating frequency range is from DC to 150 GHz, achieving ultra-wideband performance and meeting the requirements of different application scenarios.

[0025] Furthermore, the body width of the inner conductor is w 2 = 0.12 mm, the width of the inner conductor of the transition structure is w 3 = 0.135 mm, the length of the first-stage transmission line transition structure is l 2 = 0.4 mm, the length of the second-stage transmission line transition structure is l 3 = 0.15 mm, and the length and width of the pads are l 4 = 0.135 mm and w 4 = 0.1 mm; the body width of the inner conductor w 2 = 0.12 mm and the width of the inner conductor of the transition structure w 3 = 0.135 mm of the matching design ensures a smooth transition of impedance, effectively reducing the reflection loss caused by mutations during transmission, thereby improving the stability of high-frequency signal transmission; the two-stage transition of the first-stage transmission line and the second-stage transmission line realizes a smoother change in the field distribution, improving the working bandwidth and signal integrity. The length l 4 = 0.135 mm and width w 4=0.1mm ensures reliable welding performance, while keeping the contact resistance small, optimizing the coupling effect of radio frequency energy, and improving the stability of load terminal matching.

[0026] Furthermore, the micro coaxial package structure includes an inner conductor, an outer conductor, and a dielectric support bar. The inner conductor is arranged inside the outer conductor through the dielectric support bar. The dielectric support bar is arranged along the circumference of the inner conductor. Both the inner conductor and the outer conductor are located in the first layer to the eighth layer. The direction of signal transmission is perpendicular to the plane where the pad is located, and the operating frequency is from DC to 130 GHz, achieving ultra-wideband performance and meeting the requirements of different application scenarios.

[0027] Furthermore, the diameter of the inner conductor in the first layer is d 3 =0.342mm, and the diameter of the inner conductor in the eighth layer is d 4 =0.173mm; the diameter of the outer conductor in the first layer is d 1 =0.8mm, and the diameter of the outer conductor in the eighth layer is d 2 =0.4mm. The diameter of the inner conductor in the first layer of the micro coaxial is d 3 =0.342mm, and the diameter of the outer conductor is d 1 =0.8mm, which can be compatible with 1mm and 0.8mm connectors. From the first layer to the eighth layer, the outer conductor gradually decreases from d 1 =0.8mm to d 2 =0.4mm, and the inner conductor gradually decreases from d 3 =0.342mm to d 4 =0.173mm. Such a gradient design ensures the continuous change of the impedance of the transmission line, reduces the reflection loss caused by impedance mutation, improves the matching effect, thereby expanding the working frequency range. In terms of mechanical stability, the layer-by-layer transition design between the port and the outer conductor and the inner conductor avoids stress concentration, improves the mechanical stability of the structure, and ensures the reliability of the welding area.

[0028] Furthermore, the inner conductor is provided with a transition structure. The transition structure includes two-section transmission lines. The inner conductor of the first-section transmission line is located in the fourth and fifth layers, and the inner conductor of the second-section transmission line transition structure is located above the fifth layer. A pad is formed on the inner conductor. The width of the main body of the inner conductor is w 2 =0.12mm, and the width of the inner conductor of the transition structure is w 3= 0.135 mm, the length of the first-stage transmission line transition structure is l 2 = 0.4 mm, the length of the second-stage transmission line transition structure is l 3 = 0.15 mm, the length and width of the pad are l 4 = 0.135 mm and w 4 = 0.1 mm; This design ensures a smooth transition of impedance, effectively reducing the reflection loss caused by mutations during transmission, thereby improving the stability of high-frequency signal transmission; The double-stage transition of the first-stage transmission line transition structure and the second-stage transmission line transition structure realizes a smoother change in field distribution, increasing the working bandwidth and signal integrity; The length l 4 = 0.135 mm and width w 4 = 0.1 mm ensure reliable soldering performance, while having a small contact resistance, optimizing the coupling effect of radio frequency energy, and improving the stability of load terminal matching. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the prior art solutions, the following will briefly introduce the drawings used in the embodiments or the prior art solutions. It should be noted that the drawings described below are only some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without creative efforts.

[0030] Figure 1 Schematic diagram of an eight-layer process used for a microcoaxial load structure with ultra-wideband performance provided by an embodiment of the present invention;

[0031] Figure 2 Overall model schematic diagram of the first design of a microcoaxial load structure with ultra-wideband performance provided by an embodiment of the present invention;

[0032] Figure 3a Microcoaxial package outer conductor and dielectric support strip of the first design of a microcoaxial load structure with ultra-wideband performance provided by an embodiment of the present invention, Figure 3b Microcoaxial package inner conductor and dielectric support strip of the first design of a microcoaxial load structure with ultra-wideband performance provided by an embodiment of the present invention;

[0033] Figure 4The simulation result of S-parameters for the first design of a micro-coaxial load structure with ultra-wideband performance provided by an embodiment of the present invention. In the figure, the horizontal axis is the operating frequency (Frequency), and the vertical axis is the return loss (S11) of the micro-coaxial load structure.

[0034] Figure 5 Schematic diagram of the overall model for the second design of a micro-coaxial load structure with ultra-wideband performance provided by an embodiment of the present invention;

[0035] Figure 6a Bottom view schematic diagram of the micro-coaxial package for the second design of a micro-coaxial load structure with ultra-wideband performance provided by an embodiment of the present invention, Figure 6b Top view schematic diagram of the micro-coaxial package for the second design of a micro-coaxial load structure with ultra-wideband performance provided by an embodiment of the present invention;

[0036] Figure 7 Cross-sectional view of the micro-coaxial package for the second design of a micro-coaxial load structure with ultra-wideband performance provided by an embodiment of the present invention;

[0037] Figure 8 The simulation result of S-parameters for the second design of a micro-coaxial load structure with ultra-wideband performance provided by an embodiment of the present invention. In the figure, the horizontal axis is the operating frequency (Frequency), and the vertical axis is the return loss (S11) of the micro-coaxial load structure.

[0038] In the drawings, 1, inner conductor; 2, outer conductor; 3, dielectric support bar; 4, quartz sheet; 5, thin film resistor; 6, metal pad; 7, port. Detailed implementation manners

[0039] To make the objectives, features, and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. It should be noted that the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts fall within the protection scope of the present invention.

[0040] In the description of the embodiments of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "top surface", "bottom surface", "left side", "right side", "horizontal direction", "vertical direction", "up", and "down" are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than being construed as indicating that the indicated elements or devices are in a specific orientation.

[0041] It should be noted that in the description of the embodiments of the present invention, the orientation or positional relationship indicated by terms such as "top surface" and "bottom surface" is based on the orientation or positional relationship shown in the drawings. This is only for the convenience of describing the embodiments of the present invention and simplifying the description, and should not be construed as indicating that the indicated elements or devices are in a specific orientation.

[0042] In the description of the embodiments of the present invention, the given structural dimensions 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. The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

[0043] Please refer to Figure 1 , Figure 1 which is a schematic diagram of an eight-layer process used for a micro coaxial load structure with ultra-wideband performance provided by the embodiments of the present invention. The micro coaxial transmission line includes an inner conductor 1, an outer conductor 2, and a dielectric support bar 3. The inner conductor 1 is arranged inside the outer conductor 2, and the inner conductor 1 is suspended inside the outer conductor 2 through a plurality of dielectric support bars 3. A plurality of dielectric support bars 3 are arranged at intervals along the length direction of the micro coaxial transmission line; structurally, it can be divided into eight layers, and the thickness of each layer structure h av = 0.1 mm, and the total thickness h tot = 0.8 mm. For convenience of description, the fifth layer can be divided into an upper layer and a lower layer, Figure 1 as shown L 51 is the lower layer of the fifth layer and L 52 is the upper layer of the fifth layer. The dielectric support bar 3 is located in the lower layer of the fifth layer, and the thickness of the dielectric support bar 3 H SU8 = 0.04 mm.

[0044] The present invention provides two structural designs. The quartz substrate is flip-chip welded to the inner conductor 1 and the outer conductor 2 on the sixth layer of the micro-coaxial package. The signal transmission direction is parallel to the plane where the pads are located, realizing the function of an ultra-wideband load with a working frequency range from DC to 150 GHz. The quartz substrate is flip-chip welded to the inner conductor 1 and the outer conductor 2 on the eighth layer of the micro-coaxial package. The signal transmission direction is perpendicular to the plane where the pads are located, also realizing the function of an ultra-wideband load with a working frequency from DC to 130 GHz. The inverted quartz substrate helps to fix the relative positions of the inner conductor 1 and the outer conductor 2, enhancing the mechanical stability of the overall structure. During the processing, to ensure the processing accuracy and consistency of the structure, based on the metal additive manufacturing process, the metal additive manufacturing process combined with photolithography, electroplating, and chemical mechanical polishing processes can enable high-precision design and manufacturing of the details of the micro-coaxial package structure. For example, the thickness of the dielectric support bar 3 in the fifth layer is only 0.04 mm, but its uniformity and mechanical properties play a crucial role in the stability of the overall performance.

[0045] Example 1, please refer to Figure 2 、 Figure 3a 、 Figure 3b and Figure 4 , Figure 2 which is a schematic diagram of the overall model of the first design of a micro-coaxial load structure with ultra-wideband performance provided by the embodiment of the present invention; Figure 3a which is a schematic diagram of the structure of the outer conductor 2 and the dielectric support bar 3 of the micro-coaxial package structure of the first design of a micro-coaxial load structure with ultra-wideband performance provided by the embodiment of the present invention, Figure 3b which is a schematic diagram of the structure of the inner conductor 1 and the dielectric support bar 3 of the micro-coaxial package structure of the first design of a micro-coaxial load structure with ultra-wideband performance provided by the embodiment of the present invention; Figure 4 which is the S-parameter simulation result of the first design of a micro-coaxial load structure with ultra-wideband performance provided by the embodiment of the present invention. The abscissa is the working frequency, and the ordinate is the return loss S11.

[0046] The first micro-coaxial load structure includes a micro-coaxial package structure and a quartz substrate. The quartz substrate is disposed on the micro-coaxial package structure and is electrically connected to the micro-coaxial package structure, as Figure 2As shown, the micro-coaxial package structure follows the design specifications of an eight-layer process. The micro-coaxial package structure includes an inner conductor 1, an outer conductor 2, and a dielectric support bar 3. Multiple release holes are provided on the outer conductor 2 for washing the glue. The quartz substrate is integrated with the micro-coaxial package by means of reverse soldering. The quartz substrate includes a quartz sheet 4, a thin-film resistor 5, and a metal pad 6. The thin-film resistor 5 and the metal pad 6 are located on the surface of the quartz sheet 4. There are three metal pads 6. The middle metal pad 6 is soldered to the inner conductor 1, and the metal pads 6 on both sides are soldered to the outer conductor 2. The thin-film resistor 5 is located between the metal pads 6 and is used to absorb the electromagnetic energy at the terminal, acting as a load. The sheet resistance of the thin-film resistor 5 is 50 Ω. The metal pad 6 can be made of gold.

[0047] The port 7 of the micro-coaxial package structure is located at the rightmost side in the orientation shown in Figure 2 The type of the port 7 is a rectangular cross-section coaxial interface. The soldering position of the micro-coaxial package structure is on the upper surfaces of the inner conductor 1 and the outer conductor 2 in the sixth layer, as shown in Figure 3a Specifically, the bottom surface of the outer conductor 2 of the micro-coaxial package structure is located in the first layer, the top surface of the outer conductor 2 is located in the eighth layer, and the side walls of the outer conductor 2 are located in the second to seventh layers. At the location where the quartz substrate is provided, the outer conductor 2 on the upper layer of the fifth layer extends inward to form two pads. The length and width of the outer conductor 2 that extends inward to form the pads are l 1 = 0.135 mm and w 1 = 0.065 mm. The direction of signal transmission is parallel to the plane where the pads are located, as shown in Figure 3b The inner conductor 1 transitions from the fourth layer and the fifth layer to the sixth layer using a transition structure, and then a pad is formed on the inner conductor 1. The transition structure includes two sections of transmission lines. The inner conductor 1 of the first section of the transmission line is located in the fourth and fifth layers, and the inner conductor 1 of the second section of the transmission line is located on the upper layer of the fifth layer. The inner conductor 1 of the second section of the transmission line forms a pad in the sixth layer. The width of the body of the inner conductor 1 is w 2 = 0.12 mm, the width of the inner conductor 1 of the two sections of the transmission lines is w 3 = 0.135 mm, the length of the first section of the transmission line is l 2 = 0.4 mm, the length of the second section of the transmission line is l 3 = 0.15 mm, and the length and width of the pad are l 4 = 0.135 mm and w 4 = 0.1 mm. The width of the body of the inner conductor 1 w 2= 0.12 mm and the width of the inner conductor 1 of the transition structure w 3 The matching design with = 0.135 mm ensures a smooth transition of impedance, effectively reducing the reflection loss caused by mutations during transmission, thereby improving the stability of high-frequency signal transmission. The double-stage transition of the first-stage transmission line transition structure and the second-stage transmission line transition structure achieves a smoother change in the field distribution, improving the working bandwidth and signal integrity. The length of the pad l 4 = 0.135 mm and the width w 4 = 0.1 mm ensure reliable soldering performance, while having a relatively small contact resistance, optimizing the coupling effect of radio frequency energy, and improving the stability of load terminal matching.

[0048] The simulation results of the first type of micro coaxial load structure are as shown in Figure 4 In the figure, the horizontal axis is the operating frequency (Frequency), and the vertical axis is the return loss (S11) of the micro coaxial load structure. It is found that within the broadband frequency range from DC to 150 GHz, the return loss of port 7 is higher than 23.5 dB, and the wave absorption performance is good. Therefore, the first type of micro coaxial load structure can be used as a miniaturized terminal load.

[0049] Example 2, please refer to Figures 5 to 8 , Figure 5 is a schematic diagram of the overall model of the second design of a micro coaxial load structure with ultra-wideband performance provided by an embodiment of the present invention; Figure 6a is a bottom view schematic diagram of the micro coaxial package structure of the second design of a micro coaxial load structure with ultra-wideband performance provided by an embodiment of the present invention, Figure 6b is a top view schematic diagram of the micro coaxial package structure of the second design of a micro coaxial load structure with ultra-wideband performance provided by an embodiment of the present invention; Figure 7 is a cross-sectional view of the micro coaxial package of the second design of a micro coaxial load structure with ultra-wideband performance provided by an embodiment of the present invention; Figure 8 is the S-parameter simulation result of the second design of a micro coaxial load structure with ultra-wideband performance provided by an embodiment of the present invention. The abscissa is the operating frequency, and the ordinate is the return loss S11.

[0050] The second type of micro coaxial load structure is also composed of a micro coaxial package structure and a quartz substrate. The quartz substrate is arranged on the micro coaxial package structure, and the quartz substrate is electrically connected to the micro coaxial package structure, as shown in Figure 5As shown, the micro - coaxial package structure is based on the metal additive manufacturing process and is formed by an eight - layer process. It includes an inner conductor 1, an outer conductor 2, and a dielectric support bar 3. Release holes are provided on the outer conductor 2 for washing the glue. The quartz substrate is integrated with the micro - coaxial package by means of reverse soldering. The quartz substrate includes a quartz sheet 4, a thin - film resistor 5, and a metal pad 6. The thin - film resistor 5 and the metal pad 6 are located on the surface of the quartz sheet 4. The middle metal pad 6 is soldered to the inner conductor 1, and the metal pads 6 on both sides are soldered to the outer conductor 2. The thin - film resistor 5 is located between the pads and is used to absorb the electromagnetic energy at the terminal, acting as a load. The sheet resistance of the thin - film resistor 5 is also designed to be 50Ω.

[0051] The position of the port 7 of the micro - coaxial package structure is at Figure 6a and Figure 7 the lower surfaces of the inner conductor 1 and the outer conductor 2 of the first layer in the shown orientation. The type of the port 7 is a 1 - mm circular coaxial interface, as Figure 6a shown, the soldering positions of the micro - coaxial package structure are on the upper surfaces of the inner conductor 1 and the outer conductor 2 of the eighth layer, as Figure 6b shown. There are inner conductor 1 and outer conductor 2 in the structures from the first layer to the eighth layer. In order to match the positions of the metal pads 6 on both sides of the quartz substrate, from the first layer to the eighth layer, the diameter of the outer conductor 2 gradually decreases. The diameter of the outer conductor 2 in the first layer is d 1 = 0.8mm, and the diameter of the outer conductor 2 in the eighth layer is d 2 = 0.4mm; the diameter of the inner conductor 1 also gradually decreases. The diameter of the inner conductor 1 in the first layer is d 3 = 0.342mm, and the diameter of the inner conductor 1 in the eighth layer is d 4 = 0.173mm. The direction of signal transmission is perpendicular to the plane where the metal pads 6 are located, as Figure 7 shown. In order to be compatible with connectors with diameters of 1mm and 0.8mm, the diameter of the inner conductor 1 in the first layer of the micro - coaxial is d 3 = 0.342mm, and the diameter of the outer conductor 2 is d 1 = 0.8mm. From the first layer to the eighth layer, the outer conductor decreases from d 1 = 0.8mm gradually to d 2 = 0.4mm, and the inner conductor 1 decreases from d 3 = 0.342mm gradually to d 4= 0.173 mm. Such a gradient design ensures the continuous change of the impedance of the transmission line, reduces the reflection loss caused by impedance mutation, improves the matching effect, and thus expands the working frequency range. In terms of mechanical stability, the layer-by-layer transition design between port 7, outer conductor 2, and inner conductor 1 avoids stress concentration, improves the mechanical stability of the structure, and ensures the reliability of the welding area.

[0052] The simulation results of the second type of micro coaxial load structure are as Figure 8 shown. In the figure, the horizontal axis is the working frequency (Frequency), and the vertical axis is the return loss (S11) of the micro coaxial load structure. It is thus found that within the broadband frequency range from DC to 130 GHz, the return loss of port 7 is higher than 20.5 dB, and the wave absorption performance is good. Therefore, the second type of micro coaxial load structure can also be used as a miniaturized termination load.

[0053] The present invention can provide a millimeter-wave spread-spectrum module. By using the above two types of micro coaxial load structures with ultra-wideband performance as the termination load or matching load, it helps to promote the further miniaturization and high integration of microwave and millimeter-wave devices and microsystems.

[0054] The above is the description of a design method and a manufacturing method of a micro coaxial load structure with ultra-wideband performance provided by the present invention, which only illustratively explains the principle and efficacy of the present invention, rather than limiting the present invention. For those skilled in the art, according to the idea of the embodiments of the present invention, there will be changes in the specific implementation manner and application scope. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention. In summary, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A micro-coaxial load structure with ultra-wideband performance, characterized in that: The invention comprises a micro-coaxial packaging structure and a quartz substrate, wherein the quartz substrate is arranged on the micro-coaxial packaging structure in an inverted manner, and the quartz substrate is electrically connected to the micro-coaxial packaging structure; the quartz substrate comprises a quartz plate (4), a thin film resistor (5) and a metal pad (6), the thin film resistor (5) and the metal pad (6) are arranged on the surface of the quartz plate (4), the thin film resistor (5) is located between the metal pads (6), and the metal pad (6) is used to connect the micro-coaxial packaging structure; the micro-coaxial load structure is formed based on a metal additive manufacturing process; the micro-coaxial packaging structure comprises an inner conductor (1), an outer conductor (2) and a dielectric support strip (3), the port (7) of the micro-coaxial packaging structure is a coaxial interface with a rectangular cross-section; the inner conductor (1) is suspended on the inner side of the outer conductor (2) through a plurality of dielectric support strips (3), and a plurality of dielectric support strips (3) are arranged at intervals along the length direction of the micro-coaxial packaging structure; the inner conductor (1) is provided with a transition structure, the transition structure comprising two connected transmission lines, the inner conductor (1) of the first transmission line is located at the fourth and fifth layers, the inner conductor (1) of the second transmission line is located at the upper layer of the fifth layer, and the inner conductor (1) where the second transmission line is located forms a pad on the sixth layer.

2. The micro-coaxial load structure with ultra-wideband performance according to claim 1, characterized in that: Three metal pads (6) are provided, the middle metal pad (6) is electrically connected to the inner conductor (1), and the metal pads (6) on both sides are electrically connected to the outer conductor (2).

3. The micro-coaxial load structure with ultra-wideband performance according to claim 1, characterized in that: The total thickness is 0.8mm; the thickness of the quartz substrate is 0.127mm.

4. The micro-coaxial load structure with ultra-wideband performance according to claim 1, characterized in that: The body width of the inner conductor (1) w 2 = 0.12 mm, the width of the inner conductor (1) of the two transmission line segments w 3=0.135mm, the length of the first transmission line is l 2=0.4mm, the length of the second transmission line l 3=0.15mm, length of the pad l 4=0.135mm, width of pad w 4=0.1mm.

5. The micro-coaxial load structure with ultra-wideband performance according to claim 1, characterized in that: The micro-coaxial packaging structure is replaced with the following solution: the micro-coaxial packaging structure comprises an inner conductor (1), an outer conductor (2) and a dielectric support strip (3); the inner conductor (1) is arranged in the outer conductor (2) via the dielectric support strip (3); the dielectric support strip (3) is arranged along the circumference of the inner conductor (1); the micro-coaxial packaging structure is formed by an eight-layer process; the inner conductor (1) and the outer conductor (2) are both located in the first layer to the eighth layer; the port (7) of the micro-coaxial packaging structure is a circular coaxial interface; from the first layer to the eighth layer, the diameters of the outer conductor (2) and the inner conductor (1) gradually decrease; and the quartz substrate is located on the outer surface of the eighth layer of the outer conductor (2) and the inner conductor (1).

6. The micro-coaxial load structure with ultra-wideband performance according to claim 5, characterized in that: Diameter of the inner conductor (1) of the first layer d 3 = 0.342 mm, the diameter of the inner conductor (1) of the eighth layer d 4 = 0.173 mm; diameter of the outer conductor (2) of the first layer d 1 = 0.8 mm, the diameter of the outer conductor (2) of the eighth layer d 2=0.4mm.

7. A millimeter wave spectrum spreading module, characterized in that: A micro-coaxial load structure with ultra-wideband performance as described in any one of claims 1 to 6 is adopted.

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