A 1-130 GHz ultra-wideband directional coupler based on micro-coaxial technology

Abstract

The invention discloses a 1-130GHz ultra-wideband directional coupler based on a micro-coaxial process, comprising a GSG probe port and a micro-coaxial coupling line; the GSG probe port comprises an input port, a coupling port, an isolation port and a through port, the micro-coaxial coupling line comprises an outer conductor, an inner conductor and a periodic dielectric support loading structure, wherein the periodic dielectric support loading structure is SU8 with periodic holes punched in an organic material with a photosensitive property, the outer conductor is provided with a periodic process window, the input port, the coupling port, the isolation port and the through port are all coaxial line structures, the micro-coaxial coupling line is respectively separated by Y-junctions at both ends of the coupling line for mode conversion to realize coupling line-coaxial transition, impedance matching is realized by the coaxial structure, and the micro-coaxial coupling line is connected to the GSG probe port; there are two inner conductors, which do not intersect; coupling degrees of 10dB and 14dB are respectively realized, and the directivities are both above 15dB, and the ultra-wideband directional coupler with a small working frequency band size has excellent working performance.

Description

Technical Field

[0001] The invention relates to the fields of wireless communication, power monitoring, measurement system and radar technology, and in particular to a 1-130 GHz ultra-wideband directional coupler based on micro-coaxial technology. Background Art

[0002] Directional coupler is a directional power coupling device and an indispensable component in communication, radar and measurement systems. With the rapid development of the communication industry, RF equipment is required to develop in the direction of miniaturization. As an important passive device in the microwave field, the research and development of ultra-wideband and miniaturized coupler chips is crucial.

[0003] Micro-coaxial is composed of a suspended central conductor and a grounded outer conductor surrounding it. Micro-coaxial is made by micro-machining technology and additive manufacturing by stacking raw materials layer by layer. Compared with traditional planar microstrip devices, millimeter-wave devices developed based on micro-coaxial technology have the characteristics of wide bandwidth, high isolation, low loss, high power capacity, etc., while retaining the advantages of high integration of planar microstrip devices. Directional couplers based on micro-coaxial technology can achieve performance requirements such as low loss, miniaturization and wide bandwidth, and have huge application potential. Summary of the invention

[0004] In order to solve the problems existing in the prior art, the present invention provides a 1-130 GHz ultra-wideband directional coupler based on a micro-coaxial process, aiming to design an ultra-wideband directional coupler with good directivity and small size.

[0005] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present invention is: a 1-130GHz ultra-wideband directional coupler based on micro-coaxial process, including a GSG probe port and a micro-coaxial coupling line; the GSG probe port includes an input port, a coupling port, an isolation port and a through port, the micro-coaxial coupling line includes an outer conductor, an inner conductor and a periodic dielectric support loading structure, wherein the periodic dielectric support loading structure is SU8 with periodic holes of an organic material with photosensitive properties, the outer conductor opens a periodic process window, the input port, the coupling port, the isolation port and the through port are all coaxial line structures, the micro-coaxial coupling line is respectively separated by Y-junctions at both ends to perform mode conversion to realize coupling line-coaxial transition, impedance matching is realized by the coaxial structure, and is connected to the GSG probe port; there are two inner conductors, which do not intersect, the coupling port and the isolation port are connected to the same inner conductor, and the input port and the through port are connected to the same inner conductor.

[0006] The micro-coaxial coupled line is an asymmetric multi-stage impedance ladder coupler.

[0007] The cross section of the micro-coaxial coupling line gradually increases from the input port and the coupling port to the isolation port and the through port.

[0008] The micro-coaxial inner conductor leads to a trapezoidal transition structure, SU8 is added below the transition structure for the growth of the transition structure and as a supporting structure, and a first vertical and step cylinder, a second vertical and step cylinder and a third vertical and step cylinder stacked layer by layer are arranged above the trapezoidal transition structure.

[0009] The support structure of the GSG probe port is provided with a matrix of openings.

[0010] The overall structure is a layer structure, each layer has the same thickness, and the periodic medium support loading structure is arranged between the fourth layer and the fifth layer.

[0011] The Y-junction separation coupling lines are bent outwards by 180 degrees and then connected to the input port, the coupling port, the isolation port and the through port respectively.

[0012] The angle between the axes of the input port, the coupled port, the isolated port and the through port and the micro-coaxial coupling line is 45°.

[0013] Compared with the prior art, the present invention has at least the following beneficial effects: the physical size of the coupling line is increased by Y-shaped junctions at both ends of the micro-coaxial coupling line structure, and the parasitic coupling generated by the periodic dielectric support loading structure SU8 is weakened; the micro-coaxial coupling line is separated by Y-shaped junctions at both ends to perform mode conversion to realize coupling line-coaxial transition, and then impedance matching is realized through the coaxial structure; the coupling degree is 10dB and 14dB respectively, the directivity is more than 15dB, the working frequency band is wide and the size is small, and the ultra-wideband directional coupler has excellent working performance.

[0014] Furthermore, a trapezoidal transition structure is led out from the inner conductor of the micro-coaxial structure, SU8 is added below the transition structure for the growth of the transition structure and as a supporting structure, and a first vertical and step cylinder, a second vertical and step cylinder and a third vertical and step cylinder are stacked layer by layer above the trapezoidal transition structure; the impedance of the coupling port is matched, and a step-gradient structure is used to realize the coaxial-GSG probe port structure model for on-wafer testing, so as to minimize the insertion loss.

[0015] Furthermore, a matrix of openings is provided on the support structure of the GSG probe port to avoid the generation of high-order modes at high frequencies (130 GHz). BRIEF DESCRIPTION OF THE DRAWINGS

[0016] 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.

[0017] Figure 1 A schematic diagram of an eight-layer process used in an ultra-wideband directional coupler based on a micro-coaxial process provided in an embodiment of the present invention;

[0018] Figure 2 An oblique isometric diagram of a 1-130 GHz ultra-wideband directional coupler A based on micro-coaxial technology provided in an embodiment of the present invention;

[0019] Figure 3 A cross-sectional view of a 1-130 GHz ultra-wideband directional coupler A based on micro-coaxial technology provided in an embodiment of the present invention;

[0020] Figure 4 A perspective view of a 1-130 GHz ultra-wideband directional coupler A based on micro-coaxial technology provided in an embodiment of the present invention;

[0021] Figure 5 The S-parameter simulation results of a 1-130 GHz ultra-wideband directional coupler A based on micro-coaxial technology provided in an embodiment of the present invention;

[0022] Figure 6 Directivity simulation results of a 1-130 GHz ultra-wideband directional coupler A based on micro-coaxial technology provided in an embodiment of the present invention;

[0023] Figure 7 An oblique isometric diagram of a 1-130 GHz ultra-wideband directional coupler B based on micro-coaxial technology provided in an embodiment of the present invention;

[0024] Figure 8 A cross-sectional view of a 1-130 GHz ultra-wideband directional coupler B based on micro-coaxial technology provided in an embodiment of the present invention;

[0025] Fig. 9 A perspective view of a 1-130 GHz ultra-wideband directional coupler B based on micro-coaxial technology provided in an embodiment of the present invention;

[0026] Fig.10 The S-parameter simulation results of a 1-130 GHz ultra-wideband directional coupler B based on micro-coaxial technology provided in an embodiment of the present invention;

[0027] Fig.11Directivity simulation results of a 1-130 GHz ultra-wideband directional coupler B based on micro-coaxial technology provided in an embodiment of the present invention;

[0028] Fig.12 An oblique isometric diagram of a coaxial-GSG probe port of an ultra-wideband directional coupler based on a micro-coaxial process for on-wafer testing provided by an embodiment of the present invention;

[0029] Fig.13 A cross-sectional view of a coaxial-GSG probe port for on-wafer testing of an ultra-wideband directional coupler based on a micro-coaxial process provided by an embodiment of the present invention;

[0030] Fig.14 A side view of the inner conductor of a coaxial-GSG probe port of an ultra-wideband directional coupler based on a micro-coaxial process provided by an embodiment of the present invention for on-wafer testing;

[0031] Fig.15 The return loss result of the coaxial-GSG probe port of an ultra-wideband directional coupler based on micro-coaxial technology provided in an embodiment of the present invention for on-wafer testing;

[0032] Fig.16 An oblique isometric view of a coaxial-GSG probe port of an ultra-wideband directional coupler based on a micro-coaxial process for module packaging provided by an embodiment of the present invention;

[0033] Fig.17 A cross-sectional view of a coaxial-GSG probe port of a module package of an ultra-wideband directional coupler based on a micro-coaxial process provided by an embodiment of the present invention;

[0034] Fig.18 A cross-sectional view of a vertical interconnection model of a coaxial-GSG probe-1mm coaxial connector for module packaging of an ultra-wideband directional coupler based on micro-coaxial technology provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0035] 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.

[0036] In the description of the embodiments of the present invention, it needs to be understood that the orientations or positional relationships indicated by terms such as "top surface", "bottom surface", "left side", "right side", "horizontal direction" and "vertical direction" are 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.

[0037] In the description of the embodiments of the present invention, the structural dimensions given are preferred parameters. With reference to the embodiments of the present invention, the dimensional parameters of each component may be modified to further obtain the actual required performance.

[0038] See also Figure 1 , Figure 1 The eight-layer process schematic diagram of an ultra-wideband directional coupler based on a micro-coaxial process provided in an embodiment of the present invention, wherein the ultra-wideband directional coupler A comprises: a GSG probe port, a micro-coaxial coupling line, and a coupling line-coaxial transition structure, wherein the end of the micro-coaxial coupling line forms a GSG probe port through the coupling line-coaxial transition structure; the GSG probe port comprises an input port 1, a coupling port 2, an isolation port 3, and a through port 4, the micro-coaxial coupling line comprises an outer conductor 5, an inner conductor 6, and a periodic dielectric support loading structure 7, wherein the inner conductor 6 is two and does not intersect, and the coupling port 2 The same inner conductor 6 is connected to the isolation port 3, and the same inner conductor is connected to the input port 1 and the through port 4; wherein the periodic dielectric support loading structure is SU8 with periodic holes in an organic material having photosensitive properties, and the outer conductor 5 has a periodic process window, and the input port 1, the coupling port 2, the isolation port 3 and the through port 4 are all coaxial line structures, and the coupling line-coaxial transition structure separates the coupling line through a Y-shaped junction, and the end of the micro-coaxial coupling line structure is converted into two separate transmission lines to achieve mode conversion: the coupling line mode is converted into a coaxial mode, thereby achieving a coupling line-coaxial transition. The physical size of the coupling line is also increased by the Y-shaped junction at both ends of the micro-coaxial coupling line structure, which weakens the parasitic coupling generated by the periodic dielectric support loading structure SU8.

[0039] The micro-coaxial coupling line is an asymmetric multi-stage impedance ladder directional coupler designed by MATLAB and CST. The dimensions of the first and last sections of the multi-section directional coupler obtained by comprehensive design, that is, the characteristic impedance of the odd and even modes of the coupling line (determined by the distance g between the inner conductors, the distance l between the inner conductor and the outer conductor, and the width w of the inner conductor), the curve of the change of various parameters of the coupler is designed, the dimensions of other sections are directly obtained by interpolation, and rapid modeling is achieved by joint simulation of MATLAB and CST. The periodic dielectric support loading structure is SU8 with periodic perforations, which balances the mechanical and electrical properties of SU8 on the coupler.

[0040] The height of all couplers in the embodiment of the present invention is h1 equal to 0.8 mm, so the height of each layer is 0.1 mm, and the inner core height of the coupler is 0.2 mm. The thickness of all SU8 is 0.02 mm, the periodic hole size of SU8 is 0.04×0.04 mm, and SU8 is embedded in the center layer of the inner and outer conductors.

[0041] Figure 2 An oblique isometric diagram of a 1-130 GHz ultra-wideband directional coupler A based on micro-coaxial technology provided in an embodiment of the present invention, Figure 3 A cross-sectional view of a 1-130 GHz ultra-wideband directional coupler A based on micro-coaxial technology provided in an embodiment of the present invention, Figure 4 A perspective view of a 1-130 GHz ultra-wideband directional coupler A based on micro-coaxial technology provided in an embodiment of the present invention.

[0042] The 1-130 GHz ultra-wideband directional coupler A based on micro-coaxial technology has a total length of 30.2 mm and a width of 6.9 mm. Four release holes are opened on the outer conductor at intervals of 0.7 mm to facilitate cleaning of the photoresist.

[0043] Figure 5 The coupling degree, return loss, isolation and insertion loss of a 1-130GHz ultra-wideband directional coupler A based on micro-coaxial technology provided by the embodiment of the present invention are simulated and tested. Figure 6 The directivity simulation results of a 1-130 GHz ultra-wideband directional coupler A based on micro-coaxial technology provided in an embodiment of the present invention show that the coupling degree is all maintained at 10 dB and the directivity is above 15 dB, indicating that the coupler has good performance.

[0044] In order to improve the overall aspect ratio of the coupler, the port of the ultra-wideband directional coupler A is bent once to obtain the ultra-wideband directional coupler B.

[0045] Figure 7 An oblique axonometric diagram of a 1-130 GHz ultra-wideband directional coupler B based on micro-coaxial technology provided in an embodiment of the present invention, Figure 8 A cross-sectional view of a 1-130 GHz ultra-wideband directional coupler B based on micro-coaxial technology provided in an embodiment of the present invention, Fig. 9 A perspective view of a 1-130 GHz ultra-wideband directional coupler B based on micro-coaxial technology provided in an embodiment of the present invention.

[0046] In directional coupler B, the Y-junction separation coupling line is bent outward 180° and then connected to input port 1, coupling port 2, isolation port 3 and through port 4 respectively. The angle between the axis of input port 1, coupling port 2, isolation port 3 and through port 4 and the micro-coaxial coupling line is 45°.

[0047] The 1-130 GHz ultra-wideband directional coupler B based on micro-coaxial technology has a total length of 27.2 mm and a width of 13.1 mm.

[0048] The S-parameter simulation and test results of the coupling degree, return loss, isolation degree and insertion loss of the 1-130GHz ultra-wideband directional coupler B based on micro-coaxial technology are shown in Fig.10 . Fig.11 The directivity simulation result of a 1-130 GHz ultra-wideband directional coupler B based on micro-coaxial technology provided in an embodiment of the present invention shows that the coupling degree is basically maintained at 14 dB, and the directivity is above 15 dB, indicating that the coupler has good performance.

[0049] Fig.12 An oblique isometric view of a coaxial-GSG probe port of an ultra-wideband directional coupler based on a micro-coaxial process for on-wafer testing provided by an embodiment of the present invention, Fig.13 A cross-sectional view of a coaxial-GSG probe port of an ultra-wideband directional coupler based on a micro-coaxial process for on-wafer testing provided by an embodiment of the present invention, Fig.14 A side view of the inner conductor of a coaxial-GSG probe port of an ultra-wideband directional coupler based on a micro-coaxial process provided by an embodiment of the present invention for on-wafer testing;

[0050] The ultra-wideband directional coupler based on micro-coaxial process is used for the coaxial-GSG probe port of on-chip testing. The size of the micro-coaxial port is designed according to the size of the directional coupler port, and the size of the coaxial interface is designed according to the size of the 50Ω coaxial. A trapezoidal transition structure 8 is led out from the micro-coaxial inner conductor for impedance matching. The height of the trapezoidal transition structure 8 is 0.1 mm. SU8 is added below the transition structure for growth of the transition structure 8 and as a supporting structure. The first vertical and step cylinder 9, the second vertical and step cylinder 10 and the third vertical and step cylinder 11 are stacked layer by layer above the trapezoidal transition structure 8; the diameters of the first vertical and step cylinder 9, the second vertical and step cylinder 10 and the third vertical and step cylinder 11 are 0.09 mm, 0.11 mm, 0.25 mm, respectively, and the heights are 0.1 mm, 0.1 mm and 0.2 mm, respectively.

[0051] The coupler port size for on-wafer testing is designed according to the 1-130GHz 50Ω GSG probe port size, and adopts a stepped gradient structure. Through a trapezoidal transition structure, vertical and step cylinders, and a micro-coaxial line structure, a good impedance matching from the coaxial line to the GSG port is achieved, and a lower insertion loss is introduced. The SU8 design with an opening is used at the GSG probe port to avoid the generation of high-order modes at high frequencies (130GHz).

[0052] The trapezoidal transition structure refers to a gradual change in the width of the inner conductor from the inner conductor 6 to the step cylinder, and the plane projection of this section on the directional coupler is trapezoidal.

[0053] The echo of the coaxial-GSG probe port of the 1-130GHz ultra-wideband directional coupler based on micro-coaxial technology is as follows: Fig.15 As shown, its return loss can be less than 20dB in the 1-130GHz frequency band.

[0054] Fig.16 An oblique isometric view of a coaxial-GSG probe port of an ultra-wideband directional coupler based on a micro-coaxial process for module packaging provided by an embodiment of the present invention, Fig.17 A cross-sectional view of a coaxial-GSG probe port of an ultra-wideband directional coupler based on a micro-coaxial process for module packaging provided by an embodiment of the present invention, Fig.18 A cross-sectional view of a vertical interconnection model of a coaxial-GSG probe-1mm coaxial connector for module packaging of an ultra-wideband directional coupler based on micro-coaxial technology provided in an embodiment of the present invention.

[0055] The coupler port size for module packaging is designed according to the 1-130GHz 50Ω GSG probe port size, and a good impedance matching from the coaxial line to the GSG port is achieved through two-stage trapezoidal transition structure, a single vertically upward cylinder and a micro coaxial line structure. Then the designed coaxial-GSG probe port model for module packaging is interconnected with the designed 1mm coaxial connector model, and finally the packaging structure model of the ultra-wideband directional coupler is obtained.

[0056] The ultra-wideband directional coupler based on micro-coaxial process is used for the coaxial-GSG probe port of the module package. The size of the micro-coaxial port is designed according to the size of the directional coupler port, and the size of the coaxial interface is designed according to the size of the 50Ω coaxial. Two sections of trapezoidal transitions are drawn from the micro-coaxial core for impedance matching. The height of the trapezoidal transition structure is 0.1mm. SU8 is added below the transition structure for growth of the transition structure and as a supporting structure. A single vertically upward cylinder is used above the trapezoidal transition structure for interconnection between the coupler port and the designed 1mm coaxial connector model, and finally the packaging structure model of the ultra-wideband directional coupler is obtained, wherein the height of the cylinder is 0.2mm and the diameter is 0.43mm.

[0057] The above is a description of an ultra-wideband directional coupler and a manufacturing method thereof provided by the present invention. For those skilled in the art, according to the concept of the embodiments of the present invention, there may be changes in the specific implementation and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A 1-130 GHz ultra-wideband directional coupler based on micro-coaxial technology, characterized in that: Includes GSG probe port and micro-coaxial coupling line; The GSG probe port comprises an input port (1), a coupling port (2), an isolation port (3) and a through port (4); the micro-coaxial coupling line comprises an outer conductor (5), an inner conductor (6) and a periodic dielectric support loading structure (7); the periodic dielectric support loading structure is SU8 with periodic holes made of an organic material having photosensitive properties; the outer conductor (5) has a periodic process window; the input port (1), the coupling port (2), the isolation port (3) and the through port (4) are all coaxial line structures; the micro-coaxial coupling line is respectively separated by Y-shaped junctions at both ends to perform mode conversion to realize coupling line-coaxial transition, and impedance matching is realized through the coaxial structure, and the micro-coaxial coupling line is connected to the GSG probe port; there are two inner conductors (6) that do not intersect; the coupling port (2) and the isolation port (3) are connected to the same inner conductor (6); the input port (1) and the through port (4) are connected to the same inner conductor.

2. The 1-130 GHz ultra-wideband directional coupler based on micro-coaxial technology according to claim 1, characterized in that: The micro-coaxial coupled line is an asymmetric multi-stage impedance ladder coupler.

3. The 1-130 GHz ultra-wideband directional coupler based on micro-coaxial technology according to claim 1, characterized in that: The cross section of the micro-coaxial coupling line gradually increases from the input port (1) and the coupling port (2) to the isolation port (3) and the through port (4).

4. The 1-130 GHz ultra-wideband directional coupler based on micro-coaxial technology according to claim 1, characterized in that: A micro-coaxial inner conductor leads to a trapezoidal transition structure (8), SU8 is added below the transition structure to serve as the growth of the transition structure (8) and as a supporting structure, and a first vertical and step cylinder (9), a second vertical and step cylinder (10) and a third vertical and step cylinder (11) are arranged above the trapezoidal transition structure (8) in layers.

5. The 1-130 GHz ultra-wideband directional coupler based on micro-coaxial technology according to claim 4, characterized in that: The support structure of the GSG probe port is provided with a matrix of openings.

6. The 1-130 GHz ultra-wideband directional coupler based on micro-coaxial technology according to claim 1, characterized in that: The overall structure is (8) layers, each layer has the same thickness, and the periodic medium support loading structure is arranged between the fourth layer and the fifth layer.

7. The 1-130 GHz ultra-wideband directional coupler based on micro-coaxial technology according to claim 1, characterized in that: The Y-junction separation coupling lines are bent outwards by 180 degrees and then respectively connected to the input port (1), the coupling port (2), the isolation port (3) and the through port (4).

8. The 1-130 GHz ultra-wideband directional coupler based on micro-coaxial technology according to claim 1, characterized in that: The angle between the axes of the input port (1), the coupling port (2), the isolation port (3) and the through port (4) and the micro-coaxial coupling line is 45 degrees.

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