Micro coaxial load structure with ultra wide band performance and millimeter wave spread spectrum module

Abstract

The invention discloses a micro-coaxial load structure with ultra-wideband performance and a millimeter wave spread spectrum module, and belongs to the technical field of microwave and millimeter waves, the micro-coaxial load structure comprises a micro-coaxial packaging structure and a quartz substrate, the quartz substrate is arranged on the micro-coaxial packaging structure in an inverted buckling mode, and the quartz substrate is electrically connected with the micro-coaxial packaging structure; the quartz substrate comprises a quartz plate, metal bonding pads and a thin-film resistor, the metal bonding pads and the thin-film resistor are located on the surface of the quartz plate, the thin-film resistor is located between the bonding pads, and the metal bonding pads are used for connecting the micro-coaxial packaging structure; the function of an ultra-wideband load is realized, and when the signal transmission direction is parallel to the plane where the bonding pad is located, the working frequency range is from DC to 150GHz; when the signal transmission direction is perpendicular to the plane where the bonding pad is located, the working frequency ranges from DC to 130 GHz. The inverted quartz substrate is beneficial for fixing the relative position of the inner conductor and the outer conductor, and the mechanical stability of the whole structure is enhanced.

Description

Technical Field

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

[0002] In the microwave and millimeter wave frequency band, due to the limitations of transmission line structures such as waveguides and microstrip lines and traditional processing technologies such as CNC and PCB, it is difficult to achieve low loss, high-density integration and one-piece molding. In the process of microwave and millimeter wave systems developing towards the goals of miniaturization, integration and lightweight, copper-based air micro-coaxial technology came into being. This technology adopts the idea of ​​layer-by-layer processing and integrates multiple micro-processing processes such as lithography, electroplating and chemical mechanical polishing. It 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, so the micro-coaxial device has the characteristics of low loss and small size. In addition, thanks to the quasi-closed structure and TEM single-mode transmission characteristics of the micro-coaxial transmission line, the micro-coaxial device also has the advantages of high isolation between lines, wide operating frequency band and easy integration with active chips, which is very suitable for designing high-performance microwave millimeter-wave microsystems. For some multi-port devices (such as couplers) and microsystems (such as millimeter-wave spectrum expansion modules), the unused ports need to be connected to the load structure, which is usually connected to the terminal of the circuit, so it is also called a terminal load or matching load.

[0004] RF coaxial loads are widely used in radio equipment, electronic instruments and various equipment, mainly for testing RF signal transmission systems and end connections of electronic equipment systems. In the system, RF coaxial loads can perform impedance matching on spare channels and test ports of unused equipment, thereby ensuring impedance matching of signals and significantly reducing signal leakage from unused ports and mutual interference between systems. As an important component of the RF transmission system, its performance directly affects the overall performance of the entire system.

[0005] However, the existing RF coaxial load structure mainly relies on external coaxial load or waveguide load. Although this design can meet the basic performance requirements, it significantly increases the system packaging volume and limits the advantages of micro-coaxial structure in highly integrated and miniaturized systems. In addition, this type of load structure often faces frequency band restrictions and high power consumption when achieving ultra-wideband performance.

[0006] The patent application with publication number CN118589177A proposes a high-power microwave millimeter-wave load solution with an electromagnetic field constraint structure, which is composed of an electromagnetic field constrained metal carrier, a high-power load and gold wire. The concave electromagnetic field constrained metal carrier is used to improve the load performance and reduce the impact on the frequency response of the high-power microwave circuit. It focuses on solving the performance problems of the high-power load in the high-frequency band, such as the operating frequency range, standing wave ratio and cost, and does not focus on the design of ultra-wideband performance and related micro-coaxial structures.

[0007] The patent application with 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 back cover, and uses a sheet resistor to reduce the volume and improve the connection reliability. The patent is mainly devoted to optimizing the structure of the coaxial load to achieve miniaturization and high-reliability connection. The pursuit of ultra-wideband performance is not its focus, and no in-depth research has been conducted on the complex design of the micro-coaxial structure and the ultra-wideband frequency coverage.

[0008] Therefore, developing a compact micro-coaxial load structure with ultra-wideband characteristics is crucial to promoting the further miniaturization and high integration of microwave millimeter wave devices and microsystems. This type of structure not only needs to achieve excellent impedance matching performance within an ultra-wide frequency band, but also needs to take into account the feasibility of the processing technology and cost control to meet the needs of practical applications. The breakthrough of this technology will provide a higher performance and higher reliability solution for the next generation of microwave millimeter wave systems, and will have a far-reaching impact on the development of wireless communications, radar detection, precision instruments and other fields, and has important practical significance. Summary of the invention

[0009] The main purpose of the present invention is to provide a micro-coaxial load structure with 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, and the quartz substrate includes a quartz sheet, a metal pad and a thin film resistor; the quartz substrate is invertedly welded to the inner conductor and the outer conductor of the micro-coaxial package, and the inverted quartz substrate helps to fix the relative position of the inner conductor and the outer conductor, thereby enhancing the mechanical stability of the overall structure.

[0010] In order to achieve the above-mentioned purpose, the present invention provides a micro-coaxial load structure with ultra-wideband performance, comprising a micro-coaxial packaging structure and a quartz substrate, 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 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, the thin film resistor is located between the metal pads, and the metal pad is used to connect the micro-coaxial packaging structure.

[0011] Furthermore, three metal pads are provided, 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] Furthermore, the micro-coaxial load structure is formed based on a metal additive manufacturing process, with a thickness of each layer of 0.1 mm and a total thickness of 0.8 mm; the thickness of the quartz substrate is 0.127 mm.

[0013] Furthermore, the micro-coaxial packaging structure includes an inner conductor, an outer conductor and a dielectric support bar, and the port of the micro-coaxial packaging structure is a rectangular cross-section coaxial interface; the inner conductor is suspended on the inner side of the outer conductor through multiple dielectric support bars, and multiple dielectric support bars are spaced apart along the length direction of the micro-coaxial packaging structure.

[0014] Furthermore, the micro-coaxial packaging structure is formed using an eight-layer process, the fifth layer is divided into an upper layer and a lower layer, the dielectric support strip is located on the lower layer of the fifth layer, the lower wall of the outer conductor is located on the first layer, the upper wall of the outer conductor is located on the eighth layer, the side wall of the outer conductor is located on the second to seventh layers, and where the quartz substrate is set, the side wall of the outer conductor at the upper layer of the fifth layer extends inward to form two pads; the pad on the inner conductor is located on the sixth layer of the inner conductor.

[0015] Furthermore, a transition structure is provided in the inner conductor, which includes two connected transmission line sections, the inner conductor of the first transmission line section is located at the fourth and fifth layers, the inner conductor of the second transmission line section is located at the upper layer of the fifth layer, and a pad is formed on the sixth layer of the inner conductor of the second transmission line section.

[0016] Furthermore, the body width of the inner conductor w 2 = 0.12 mm, the width of the inner conductor of the two transmission lines 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.

[0017] Furthermore, the micro-coaxial packaging structure includes an inner conductor, an outer conductor and a dielectric support bar. The inner conductor is arranged in the outer conductor through the dielectric support bar. The dielectric support bar is arranged along the circumference of the inner conductor. The micro-coaxial packaging structure is formed by an eight-layer process. The inner conductor and the outer conductor are both located from the first layer to the eighth layer. The port 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 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 inner conductor diameter of the first layer d3=0.342mm, the inner conductor diameter of the eighth layer d 4=0.173mm; the outer conductor diameter of the first layer d 1=0.8mm, the outer conductor diameter of the eighth layer d 2=0.4mm.

[0019] The present invention also provides a millimeter wave spectrum expansion 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: the present invention effectively fixes the positions of the inner conductor and the outer conductor through the innovative design of the inverted quartz substrate, which not only significantly improves the mechanical stability, but also enhances the reliability and processing accuracy of the load structure; the present invention improves the design of the port of the micro-coaxial broadband load structure so that it can be reliably integrated and interconnected with the peripheral circuit, making the micro-coaxial broadband load structure easier to test and integrate, and has a wide adaptability, and can be widely used in 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 to absorb the electromagnetic energy of the terminal and act as a load. The square resistance of the thin film resistor is designed to be 50Ω to achieve better impedance matching.

[0022] Furthermore, the micro-coaxial load structure provided by the present invention is small in size and uses copper-based air micro-coaxial technology 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 vertical distribution, reducing the difficulty of process manufacturing. The total thickness of 0.8 mm provides sufficient mechanical support while ensuring the miniaturization of the chip structure, ensuring that the micro-coaxial package has good structural reliability. The quartz thickness of 0.127 mm ensures the uniformity of the electric field distribution, and can maintain excellent dielectric properties in the high-frequency range, reducing interference with signal propagation.

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

[0024] Furthermore, the micro-coaxial packaging structure includes an inner conductor, an outer conductor and a dielectric support bar, and the port of the micro-coaxial load structure is a rectangular cross-section coaxial interface; the inner conductor is suspended on the inner side of the outer conductor through a plurality of dielectric support bars, and a plurality of dielectric support bars are spaced apart along the length direction of the micro-coaxial packaging structure; the direction of signal transmission is parallel to the plane where the metal pad is located, and the operating frequency range is DC to 150GHz, achieving ultra-wideband performance, which is sufficient to meet the needs of different application scenarios.

[0025] Furthermore, the body width of the inner conductor is w 2=0.12mm, the width of the inner conductor of the transition structure is w 3=0.135mm, the length of the first section of the transmission line transition structure is l 2=0.4mm, the length of the second transmission line transition structure is l 3=0.15mm, the length and width of the pad are l 4 = 0.135 mm and w 4 = 0.1 mm; the width of the inner conductor w 2 = 0.12 mm and the inner conductor width of the transition structure w The matching design of 3=0.135mm 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 between the first transmission line and the second transmission line achieves a smoother field distribution change, improving the working bandwidth and signal integrity. l 4 = 0.135 mm and width w 4=0.1mm ensures reliable welding performance, while making the contact resistance smaller, optimizing the coupling effect of RF energy and improving the stability of load terminal matching.

[0026] Furthermore, the micro-coaxial packaging structure includes an inner conductor, an outer conductor and a dielectric support bar. The inner conductor is arranged on the inner side of the outer conductor through the dielectric support bar. The dielectric support bar is arranged along the circumference of the inner conductor. The inner conductor and the outer conductor are both located in the first to eighth layers. The direction of signal transmission is perpendicular to the plane where the pad is located. The operating frequency is DC to 130GHz, achieving ultra-wideband performance, which can meet the needs of different application scenarios.

[0027] Furthermore, the inner conductor diameter of the first layer is d 3=0.342mm, the inner conductor diameter of the eighth layer is d 4=0.173mm; the outer conductor diameter of the first layer is d 1=0.8mm, the outer conductor diameter of the eighth layer is d 2=0.4mm. The inner conductor diameter of the first layer of micro-coaxial is d 3=0.342mm, the outer conductor diameter isd 1 = 0.8mm, compatible with 1mm and 0.8mm connectors. From the first layer to the eighth layer, the outer conductor is d 1=0.8mm gradually decreases to d 2=0.4mm, inner conductor from d 3 = 0.342 mm gradually decreases to d 4=0.173mm. Such a gradual 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 operating 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 transmission lines at both ends, the inner conductor of the first transmission line is located at the fourth and fifth layers, the inner conductor of the transition structure of the second transmission line is located at the upper layer of the fifth layer, a pad is formed on the inner conductor, and the body width of the inner conductor is w 2=0.12mm, the width of the inner conductor of the transition structure is w 3=0.135mm, the length of the first section of the transmission line transition structure is l 2=0.4mm, the length of the second transmission line transition structure is l 3=0.15mm, the length and width of the pad are l 4 = 0.135 mm and w 4=0.1mm; This design ensures a smooth transition of impedance, effectively reduces the reflection loss caused by mutations during transmission, and thus improves the stability of high-frequency signal transmission; the double-stage transition of the first transmission line transition structure and the second transmission line transition structure achieves a smoother field distribution change, improves the working bandwidth and signal integrity; the length of the pad l 4 = 0.135 mm and width w 4=0.1mm ensures reliable welding performance, while making the contact resistance smaller, optimizing the coupling effect of RF 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 drawings used in the embodiments or the prior art solutions are briefly introduced below. 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 work.

[0030] Figure 1A schematic diagram of an eight-layer process used in a micro-coaxial load structure with ultra-wideband performance provided by an embodiment of the present invention; Figure 2 A schematic diagram of an overall model of a first design of a micro-coaxial load structure with ultra-wideband performance provided by an embodiment of the present invention; Figure 3a A first design of a micro-coaxial package outer conductor and a dielectric support strip of a micro-coaxial load structure with ultra-wideband performance provided by an embodiment of the present invention, Figure 3b A first design of a micro-coaxial package inner conductor and a dielectric support strip of a micro-coaxial load structure with ultra-wideband performance provided by an embodiment of the present invention; Figure 4 The S parameter simulation result of the first design of a micro-coaxial load structure with ultra-wideband performance provided by an embodiment of the present invention, in which the horizontal axis is the operating frequency (Frequency) and the vertical axis is the return loss (S11) of the micro-coaxial load structure; Figure 5 A schematic diagram of an overall model of a second design of a micro-coaxial load structure with ultra-wideband performance provided by an embodiment of the present invention; Figure 6a A bottom view schematic diagram of a micro-coaxial package of a second design of a micro-coaxial load structure with ultra-wideband performance provided by an embodiment of the present invention, Figure 6b A schematic top view of a micro-coaxial package of a second design of a micro-coaxial load structure with ultra-wideband performance provided by an embodiment of the present invention; Figure 7 A cross-sectional view of a micro-coaxial package of a second design of a micro-coaxial load structure with ultra-wideband performance provided by an embodiment of the present invention; Figure 8 The S parameter simulation results of the second design of a micro-coaxial load structure with ultra-wideband performance provided by an embodiment of the present invention, in which the horizontal axis is the operating frequency (Frequency) and the vertical axis is the return loss (S11) of the micro-coaxial load structure.

[0031] In the attached figure, 1, inner conductor; 2, outer conductor; 3, dielectric support bar; 4, quartz sheet; 5, thin film resistor; 6, metal pad; 7, port. DETAILED DESCRIPTION

[0032] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. It should be noted that the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0033] In the description of the embodiments of the present invention, it needs to be understood that the terms "top surface", "bottom surface", "left side", "right side", "horizontal direction", "vertical direction", "up" and "down" indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and it cannot be determined that the indicated elements or devices are in a specific orientation.

[0034] It should be noted that in the description of the embodiments of the present invention, the orientation or positional relationship indicated by the terms "top surface", "bottom surface", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the embodiments of the present invention and simplifying the description, and it cannot be determined that the indicated elements or devices are in a specific orientation.

[0035] In the description of the embodiments of the present invention, the given structural dimensions are preferred parameters. With reference to the embodiments of the present invention, the dimensional parameters of each component can be modified to further obtain the actual required performance. The above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit it; although the present invention is described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features can be replaced by equivalents; 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.

[0036] See also Figure 1 , Figure 1 Schematic diagram of an eight-layer process used in a micro-coaxial load structure with ultra-wideband performance provided by an embodiment 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 on the inner side of the outer conductor 2, the inner conductor 1 is suspended on the inner side of the outer conductor 2 through a plurality of dielectric support bars 3, and a plurality of dielectric support bars 3 are arranged at intervals along the length direction of the micro-coaxial transmission line; the structure can be divided into eight layers, and the thickness of each layer is h av =0.1mm, total thickness h tot =0.8mm. For the convenience of description, the fifth layer can be divided into the upper layer and the lower layer. Figure 1 Shown L51 For the lower layer of the fifth layer and L 52 The dielectric support strip 3 is located at the lower layer of the fifth layer, and the dielectric support strip 3 has a thickness of H SU8 =0.04mm.

[0037] The present invention provides two structural designs. The quartz substrate is flip-chip welded on the sixth inner conductor 1 and outer conductor 2 of the micro-coaxial package. The direction of signal transmission is parallel to the plane where the pad is located, realizing the function of ultra-wideband load, and the operating frequency range is DC to 150GHz; the quartz substrate is flip-chip welded on the eighth inner conductor 1 and outer conductor 2 of the micro-coaxial package. The direction of signal transmission is perpendicular to the plane where the pad is located, and the function of ultra-wideband load is also realized, and the operating frequency is DC to 130GHz; the inverted quartz substrate helps to fix the relative position of the inner conductor 1 and the outer conductor 2, and enhances the mechanical stability of the overall structure. During the processing, in order to ensure the processing accuracy and consistency of the structure, based on the metal additive manufacturing process, the metal additive manufacturing process is combined with photolithography, electroplating and chemical mechanical polishing processes, which can enable the details of the micro-coaxial package structure to be designed and manufactured with high precision. For example, the thickness of the dielectric support strip 3 in the fifth layer is only 0.04mm, but its uniformity and mechanical properties play a vital role in the stability of the overall performance.

[0038] Example 1, please refer to Figure 2 , Figure 3a , Figure 3b and Figure 4 , Figure 2 A schematic diagram of an overall model of a first design of a micro-coaxial load structure with ultra-wideband performance provided by an embodiment of the present invention; Figure 3a A schematic diagram of the structure of the outer conductor 2 and the dielectric support strip 3 of a micro-coaxial packaging structure of a first design of a micro-coaxial load structure with ultra-wideband performance provided by an embodiment of the present invention, Figure 3b A schematic diagram of the structure of the inner conductor 1 and the dielectric support strip 3 of a micro-coaxial packaging structure of a first design of a micro-coaxial load structure with ultra-wideband performance provided by an embodiment of the present invention; Figure 4 The S parameter simulation results of the first design of a micro-coaxial load structure with ultra-wideband performance provided by an embodiment of the present invention, where the horizontal axis is the operating frequency and the vertical axis is the return loss S11.

[0039] The first micro-coaxial load structure includes a micro-coaxial packaging structure and a quartz substrate, the quartz substrate is arranged on the micro-coaxial packaging structure, and the quartz substrate is electrically connected to the micro-coaxial packaging structure, such as Figure 2As shown, the micro-coaxial packaging structure complies with the design specifications of the eight-layer process. The micro-coaxial packaging structure includes an inner conductor 1, an outer conductor 2 and a dielectric support strip 3. A plurality of release holes are provided on the outer conductor 2 for washing the glue. The quartz substrate is integrated with the micro-coaxial package by flip-down welding. 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. Three metal pads 6 are provided. The middle metal pad 6 is welded to the inner conductor 1, and the metal pads 6 on both sides are welded to the outer conductor 2. The thin film resistor 5 is located between the metal pads 6 to absorb the electromagnetic energy of the terminal and act as a load. The square resistance of the thin film resistor 5 is 50Ω. The metal pad 6 can be made of gold.

[0040] The port 7 of the micro-coaxial packaging structure is located at Figure 2 At the far right side of the position shown, the type of port 7 is a rectangular cross-section coaxial interface, and the welding position of the micro-coaxial packaging structure is on the upper surface of the sixth layer inner conductor 1 and outer conductor 2, as shown in FIG. Figure 3a Specifically, the bottom surface of the outer conductor 2 of the micro-coaxial packaging structure is located at the first layer, the top surface of the outer conductor 2 is located at the eighth layer, the side wall of the outer conductor 2 is located at the second to seventh layers, and at the location where the quartz substrate is set, the outer conductor 2 of the upper layer of the fifth layer extends inward to form two pads, and the length and width of the pad formed by the outer conductor 2 extending inward are respectively l 1 = 0.135 mm and w 1=0.065mm. The direction of signal transmission is parallel to the plane where the pad is located. Figure 3b As shown, the inner conductor 1 transitions from the fourth and fifth layers to the sixth layer using a transition structure, and then forms a pad 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 at the fourth and fifth layers, the inner conductor 1 of the second section of the transmission line is located at the upper layer of the fifth layer, and the sixth layer of the inner conductor 1 where the second section of the transmission line is located forms a pad. The width of the inner conductor 1 body is w 2=0.12mm, the width of the inner conductor 1 of the two transmission lines is w 3=0.135mm, the length of the first transmission line is l 2=0.4mm, the length of the second transmission line is l 3=0.15mm, the length and width of the pad are l 4 = 0.135 mm and w 4 = 0.1 mm. Width of the inner conductor 1 w 2 = 0.12 mm and the width of the inner conductor 1 of the transition structure wThe matching design of 3=0.135mm 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 transmission line transition structure and the second transmission line transition structure achieves a smoother field distribution change, improving the working bandwidth and signal integrity. The length of the pad l 4 = 0.135 mm and width w 4=0.1mm ensures reliable welding performance, while making the contact resistance smaller, optimizing the coupling effect of RF energy and improving the stability of load terminal matching.

[0041] The simulation results of the first micro-coaxial load structure are shown in Figure 4 As shown 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 in the broadband frequency range from DC to 150GHz, the return loss of port 7 is higher than 23.5dB, and the wave absorption performance is good. Therefore, the first micro-coaxial load structure can be used as a miniaturized terminal load.

[0042] Example 2, please refer to Figures 5 to 8 , Figure 5 A schematic diagram of an overall model of a second design of a micro-coaxial load structure with ultra-wideband performance provided by an embodiment of the present invention; Figure 6a A bottom view schematically shows a micro-coaxial packaging structure of a second design of a micro-coaxial load structure with ultra-wideband performance provided by an embodiment of the present invention, Figure 6b A schematic top view of a micro-coaxial packaging structure of a second design of a micro-coaxial load structure with ultra-wideband performance provided by an embodiment of the present invention; Figure 7 A cross-sectional view of a micro-coaxial package of a second design of a micro-coaxial load structure with ultra-wideband performance provided by an embodiment of the present invention; Figure 8 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 horizontal axis is the operating frequency, and the vertical axis is the return loss S11.

[0043] The second micro-coaxial load structure also consists of a micro-coaxial packaging structure and a quartz substrate. The quartz substrate is arranged on the micro-coaxial packaging structure, and the quartz substrate is electrically connected to the micro-coaxial packaging structure. Figure 5As shown, the micro-coaxial packaging structure is based on a metal additive manufacturing process and is formed using an eight-layer process, including an inner conductor 1, an outer conductor 2 and a dielectric support strip 3. A release hole is provided on the outer conductor 2 for easy glue washing. The quartz substrate is integrated with the micro-coaxial package by flip-flop welding. 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 welded to the inner conductor 1, and the metal pads 6 on both sides are welded to the outer conductor 2. The thin film resistor 5 is located between the pads to absorb the electromagnetic energy of the terminal and act as a load. The square resistance of the thin film resistor 5 is also designed to be 50Ω.

[0044] Port 7 of the micro-coaxial package structure is located at Figure 6a and Figure 7 The lower surface of the first layer inner conductor 1 and outer conductor 2 is shown in the orientation, and the type of port 7 is a 1mm circular coaxial interface, such as Figure 6a As shown, the welding position of the micro-coaxial packaging structure is on the upper surface of the inner conductor 1 and the outer conductor 2 of the eighth layer, as shown in FIG. Figure 6b The first to eighth layers of the structure all have an inner conductor 1 and an outer conductor 2. In order to match the position of the metal pads 6 on both sides of the quartz substrate, the diameter of the outer conductor 2 gradually decreases from the first layer to the eighth layer. The diameter of the outer conductor 2 of the first layer is d 1=0.8mm, the diameter of the outer conductor 2 of the eighth layer is d 2=0.4mm; the diameter of the inner conductor 1 gradually decreases, and the diameter of the inner conductor 1 of the first layer is d 3=0.342mm, the diameter of the inner conductor 1 of the eighth layer is d 4=0.173mm. The direction of signal transmission is perpendicular to the plane where the metal pad 6 is located. Figure 7 In order to be compatible with 1mm and 0.8mm diameter connectors, the inner conductor 1 of the first layer of the micro-coaxial d 3=0.342mm, the diameter of the outer conductor 2 is d 1=0.8mm. From the first layer to the eighth layer, the outer conductor is d 1=0.8mm gradually decreases to d 2 = 0.4mm, inner conductor 1 from d 3 = 0.342 mm gradually decreases to d 4=0.173mm. Such a gradual change 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 operating frequency range. In terms of mechanical stability, the layer-by-layer transition design between port 7 and the outer conductor 2 and the inner conductor 1 avoids stress concentration, improves the mechanical stability of the structure, and ensures the reliability of the welding area.

[0045] The simulation results of the second micro-coaxial load structure are shown in Figure 8As shown 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 in the broadband frequency range from DC to 130GHz, the return loss of port 7 is higher than 20.5dB, and the wave absorption performance is good. Therefore, the second micro-coaxial load structure can also be used as a miniaturized terminal load.

[0046] The present invention can provide a millimeter wave spectrum expansion module, which uses the above two micro-coaxial load structures with ultra-wideband performance as terminal loads or matching loads, which helps to promote further miniaturization and high integration of microwave millimeter wave devices and microsystems.

[0047] The above is a 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 illustrates the principle and efficacy of the present invention, and is not used to limit the present invention. For those skilled in the art, according to the ideas of the embodiments of the present invention, there will be changes in the specific implementation methods and scope of application. Anyone familiar with this technology can modify or change the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas 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 understood as a limitation on 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), wherein 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.

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 micro-coaxial load structure is formed based on the metal additive manufacturing process, with a total thickness of 0.8 mm; the thickness of the quartz substrate is 0.127 mm.

4. The micro-coaxial load structure with ultra-wideband performance according to claim 3, characterized in that: The micro-coaxial packaging structure comprises an inner conductor (1), an outer conductor (2) and a dielectric support strip (3); a 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); a plurality of dielectric support strips (3) are arranged at intervals along the length direction of the micro-coaxial packaging structure.

5. The micro-coaxial load structure with ultra-wideband performance according to claim 4, characterized in that: The micro-coaxial packaging structure is formed by an eight-layer process, the fifth layer is divided into an upper layer and a lower layer, the dielectric support strip (3) is located in the lower layer of the fifth layer, the lower wall of the outer conductor (2) is located in the first layer, the upper wall of the outer conductor (2) is located in the eighth layer, the side wall of the outer conductor (2) is located in the second to seventh layers, and at the location where the quartz substrate is provided, the side wall of the outer conductor (2) at the upper layer of the fifth layer extends inward to form two pads; the pad on the inner conductor (1) is located in the sixth layer of the inner conductor (1).

6. The micro-coaxial load structure with ultra-wideband performance according to claim 4, characterized in that: 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) of the second transmission line is located at the sixth layer to form a pad.

7. The micro-coaxial load structure with ultra-wideband performance according to claim 6, 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.

8. The micro-coaxial load structure with ultra-wideband performance according to claim 3, characterized in that: 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).

9. The micro-coaxial load structure with ultra-wideband performance according to claim 8, 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.

10. 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 9 is adopted.

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