Miniaturized broadband 180-degree filtering coupler based on micro coaxial transmission line

Abstract

The invention discloses a miniaturized broadband 180-degree filtering coupler based on a micro coaxial transmission line. Comprising a micro-coaxial outer conductor base, a first micro-coaxial open-circuit coupling line, a second micro-coaxial open-circuit coupling line, a third micro-coaxial open-circuit coupling line, a micro-coaxial short-circuit coupling line, a first micro-coaxial filtering branch knot, a second micro-coaxial filtering branch knot, a straight-through port, a coupling port, an input port and an isolation port. The first micro coaxial open-circuit coupling line, the second micro coaxial open-circuit coupling line, the third micro coaxial open-circuit coupling line and the micro coaxial short-circuit coupling line form a 180-degree broadband coupler effect, and the filter and the 180-degree coupler are fused to replace a cascade connection mode of two independent devices in a traditional design, so that the plane size of the whole system is remarkably reduced; the novel coupler is constructed by adopting the micro coaxial coupling lines, has the advantages of miniaturization, wide bandwidth and the like, and solves the problems of narrow bandwidth, single function, large size and the like of a coupler in the prior art.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and in particular to a miniaturized broadband 180° filter coupler based on a micro coaxial transmission line. Background Technology

[0002] With the development of wireless communication technology, especially in 5G millimeter-wave communication systems, couplers are widely used due to their function of providing power distribution and phase difference. With the rapid development of millimeter-wave radio frequency technology, couplers face requirements for miniaturization, high performance, and multi-functional integration. However, existing couplers generally suffer from problems such as large size, narrow bandwidth, and low integration.

[0003] Traditional branch-line directional couplers utilize a ring structure of a quarter-wavelength transmission line to achieve different power distribution ratios and a 90° phase difference at the center frequency. However, traditional branch-line couplers are limited by narrow bandwidth, poor out-of-band suppression, and poor out-of-band isolation. Related research typically focuses on a 90° output phase difference, with limited research on 180° couplers. Couplers based on resonator structures achieve a 180° coupler effect while also providing frequency selectivity by adjusting the coupling mechanism between resonators; however, these resonator-based couplers are relatively large, hindering the miniaturization of the overall system. Therefore, a novel coupler solution that combines miniaturization, high performance, and multifunctionality is urgently needed. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing a miniaturized broadband 180° filter coupler based on a micro coaxial transmission line. This miniaturized broadband 180° filter coupler based on a micro coaxial transmission line has advantages such as miniaturization and wide bandwidth, and solves the problems of narrow bandwidth, single function and large size of the coupler in the prior art.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A miniaturized broadband 180° filter coupler based on a microcoaxial transmission line includes a microcoaxial outer conductor base, a first microcoaxial open-circuit coupling line, a second microcoaxial open-circuit coupling line, a third microcoaxial open-circuit coupling line, a microcoaxial short-circuit coupling line, a first microcoaxial filter stub, a second microcoaxial filter stub, a through port, a coupling port, an input port, and an isolation port; The microcoaxial outer conductor base includes: a microcoaxial outer conductor left arm and a microcoaxial outer conductor right arm, a microcoaxial outer conductor upper arm and a microcoaxial outer conductor lower arm, a microcoaxial outer conductor upper arm wing and a microcoaxial outer conductor lower arm wing; The left arm and right arm of the microcoaxial outer conductor are arranged relatively parallel to each other along the longitudinal direction. The upper arm and lower arm of the micro-coaxial outer conductor are arranged relatively parallel to each other in the transverse direction; The left arm, upper arm, right arm, and lower arm of the microcoaxial outer conductor are connected in sequence to form a rectangle. The upper arm of the microcoaxial outer conductor is U-shaped with a left opening, one end of which is connected to the left end of the upper arm of the microcoaxial outer conductor, and the other end is open. The lower arm of the microcoaxial outer conductor is U-shaped with a right opening. One end of the wing is connected to the right end of the lower arm of the microcoaxial outer conductor, while the other end is open. The upper arm wing and the lower arm wing of the microcoaxial outer conductor are centrally symmetrical; The micro-coaxial outer conductor base has an intermediate cavity at the centerline position along its length direction; The input port and coupling port are respectively located at the left and right corners of the upper arm of the micro-coaxial outer conductor, and the through port and isolation port are respectively located at the left and right corners of the lower arm of the micro-coaxial outer conductor; The first microcoaxial open-circuit coupling line is placed longitudinally on the left arm of the outer conductor of the microcoaxial line, with its two ends connected to the input port and the through port, respectively. The second microcoaxial open-circuit coupling line is placed longitudinally on the right arm of the outer conductor of the microcoaxial line, with its two ends connected to the coupling port and the isolation port, respectively. The third microcoaxial open-circuit coupling line is placed laterally on the upper arm of the outer conductor of the microcoaxial line, with its two ends connected to the input port and the coupling port, respectively. The microcoaxial short-circuit coupling line is placed laterally on the lower arm of the outer conductor of the microcoaxial cable, with its two ends connected to the through port and the isolation port, respectively. The first microcoaxial filter stub is placed along the path of the upper arm of the outer conductor of the microcoaxial cable, with one end connected to the input port and the other end open. The second microcoaxial filter stub is placed along the path of the lower arm of the microcoaxial outer conductor, with one end connected to the isolation port and the other end open.

[0006] Furthermore, the micro-coaxial outer conductor base is made of metal, and its intermediate cavity is filled with air.

[0007] Furthermore, the height and width dimensions of the micro-coaxial outer conductor base are set to be the same, and the width of the inner wall of the intermediate cavity is 0.53mm and the height is 0.3mm; the height of the first micro-coaxial open-circuit coupling line, the second micro-coaxial open-circuit coupling line, the third micro-coaxial open-circuit coupling line, the micro-coaxial short-circuit coupling line, the first micro-coaxial filter stub, and the second micro-coaxial filter stub is set to 0.1mm.

[0008] Furthermore, the first micro-coaxial open-circuit coupling line includes two parallel transmission lines: one transmission line is connected to the input port at one end and is open at the other end; the other transmission line is connected to the through port at one end and is open at the other end. Support bars are evenly arranged on both sides of the first micro-coaxial open-circuit coupling line, and the first micro-coaxial open-circuit coupling line is supported by the support bars at the center of its corresponding intermediate cavity. The second micro-coaxial open-circuit coupling line includes two parallel transmission lines: one transmission line is connected to the isolation port at one end and is open at the other end; the other transmission line is connected to the coupling port at one end and is open at the other end. Support bars are evenly arranged on both sides of the second micro coaxial open-circuit coupling line, and the second micro coaxial open-circuit coupling line is supported by the support bars at the center of its corresponding intermediate cavity. The third micro-coaxial open-circuit coupling line includes two parallel transmission lines: one transmission line is connected to the input port at one end and is open at the other end; the other transmission line is connected to the coupling port at one end and is open at the other end. Support bars are evenly arranged on both sides of the third micro-coaxial open-circuit coupling line 300, and the third micro-coaxial open-circuit coupling line 300 is supported by the support bars at the center of its corresponding intermediate cavity.

[0009] Furthermore, the microcoaxial short-circuit coupling line includes two parallel transmission lines: one transmission line is connected to the isolation port at one end and to the corresponding microcoaxial outer conductor base through a grounding post at the other end; the other transmission line is connected to the through port at one end and to the corresponding microcoaxial outer conductor base through a grounding post at the other end. Support bars are evenly arranged on both sides of the micro-coaxial short-circuit coupling line, and the micro-coaxial short-circuit coupling line is supported by the support bars at the center of its corresponding intermediate cavity.

[0010] Furthermore, the first microcoaxial filter stub is formed by connecting a first bent coupling line and a first bent open-circuit transmission line. The first bent coupling line is placed along the front half of the path of the upper arm wing of the microcoaxial outer conductor, and the first bent open-circuit transmission line is placed along the rear half of the path of the upper arm wing of the microcoaxial outer conductor. The second microcoaxial filter stub is formed by connecting the second bent coupling line and the second bent open-circuit transmission line. The second bent coupling line is placed along the first half of the path of the lower arm wing of the outer conductor of the microcoaxial cable, and the second bent open-circuit transmission line is placed along the second half of the path of the lower arm wing of the outer conductor of the microcoaxial cable.

[0011] Furthermore, the first bent coupling line includes two bent coupling lines arranged in parallel: one end of the bent coupling line is connected to the input port and the other end is open; the other bent coupling line is open at the end closer to the input port and connected to the first bent open transmission line at the end farther from the input port. The first micro-coaxial filter stub is evenly arranged with support bars on both sides, and the first micro-coaxial filter stub is supported by the support bars at the center of its corresponding intermediate cavity. The second bent coupling line includes two bent coupling lines arranged in parallel: one end of the bent coupling line is connected to the isolation port and the other end is open; the other bent coupling line is open at the end near the input port and connected to the second bent open transmission line at the end away from the input port. The second micro-coaxial filter stub is evenly supported by support bars on both sides, and the second micro-coaxial filter stub is supported by the support bars at the center of its corresponding intermediate cavity.

[0012] Furthermore, the first microcoaxial open-circuit coupling line, the second microcoaxial open-circuit coupling line, the third microcoaxial open-circuit coupling line, the microcoaxial short-circuit coupling line, the first microcoaxial filter stub, and the second microcoaxial filter stub are made of metal; the support strip is made of SU-8 photoresist.

[0013] Furthermore, the inner conductors of the two transmission lines of the first micro-coaxial open-circuit coupling line have the same dimensions, with the length and width of the inner conductor of each transmission line being 3.16 mm and 0.04 mm, respectively, and the distance between the inner conductors of the two transmission lines being 0.02 mm; The inner conductors of the two transmission lines of the second micro-coaxial open-circuit coupling line have the same dimensions. The length and width of the inner conductor of each transmission line are 3.16 mm and 0.04 mm, respectively, and the distance between the inner conductors of the two transmission lines is 0.02 mm. The inner conductors of the two transmission lines of the third micro-coaxial open-circuit coupling line have the same dimensions. The length and width of the inner conductor of each transmission line are 3.06 mm and 0.04 mm, respectively, and the distance between the inner conductors of the two transmission lines is 0.02 mm. The inner conductors of the two transmission lines of the micro-coaxial short-circuit coupling line have the same dimensions. The length and width of the inner conductor of each transmission line are 3.06 mm and 0.03 mm, respectively, and the distance between the inner conductors of the two transmission lines is 0.02 mm. The length, width and height of the grounding post are 0.03 mm, 0.03 mm and 0.1 mm, respectively.

[0014] Furthermore, the two parallel bent coupling lines at the first bent coupling line have the same dimensions, with the length and width of the conductor inside each bent coupling line being 3mm and 0.02mm respectively, and the spacing between the conductors inside the two parallel bent coupling lines being 0.03mm; the length and width of the first bent open-circuit transmission line are 3mm and 0.05mm respectively. The two parallel bent coupling lines at the second bend coupling line have the same dimensions. The length and width of the conductor inside each bent coupling line are 3mm and 0.02mm, respectively, and the spacing between the conductors inside the two parallel bent coupling lines is 0.03mm. The length and width of the second bend open-circuit transmission line are 3mm and 0.05mm, respectively.

[0015] The present invention has the following beneficial effects: 1. This invention proposes a miniaturized broadband 180° filter coupler based on microcoaxial transmission lines. It achieves a 180° broadband coupler effect through a first microcoaxial open-circuit coupling line, a second microcoaxial open-circuit coupling line, a third microcoaxial open-circuit coupling line, and a microcoaxial short-circuit coupling line. The filter and 180° coupler are integrated, replacing the cascaded approach of two independent devices in traditional designs, significantly reducing the overall system's planar size. This invention uses microcoaxial coupling lines to construct a novel coupler, offering advantages such as miniaturization and wide bandwidth, solving problems such as narrow bandwidth, limited functionality, and large size in existing couplers.

[0016] 2. The isolation port of this invention has excellent isolation, preventing reflected signals from interfering with the front-end circuit, reducing potential instability caused by reflected signals, and improving the working efficiency and reliability of the entire communication system. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a miniaturized broadband 180° filter coupler based on a micro coaxial transmission line according to the present invention.

[0018] Figure 2 This is a top view of the structure of a miniaturized broadband 180° filter coupler based on a micro coaxial transmission line according to the present invention.

[0019] Figure 3(a) shows the S-parameter results of each input and output port when the input port of the miniaturized broadband 180° filter coupler based on micro-coaxial transmission line of the present invention is excited; Figure 3(b) shows the S-parameter results of each input and output port when the isolation port of the miniaturized broadband 180° filter coupler based on micro-coaxial transmission line of the present invention is excited.

[0020] Figure 4 This invention relates to the phase difference results between the output ports of a miniaturized broadband 180° filter coupler based on a micro coaxial transmission line.

[0021] These include: 100 First microcoaxial open-circuit coupling line, 200 Second microcoaxial open-circuit coupling line, 300 Third microcoaxial open-circuit coupling line, 400 Microcoaxial short-circuit coupling line, grounding post 430, first microcoaxial filter stub 500, 510 First bent coupling line, 520 First bent open-circuit transmission line, second microcoaxial filter stub 600, 610 Second bent coupling line, 620 Second bent open-circuit transmission line, input port 710, isolation port 720, through port 810, coupling port 820, and 900 microcoaxial outer conductor base. Detailed Implementation

[0022] The present invention will now be described in further detail with reference to the accompanying drawings and specific preferred embodiments.

[0023] In the description of this invention, it should be understood that the terms "left side," "right side," "upper part," "lower part," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. "First," "second," etc., do not indicate the importance of the components, and therefore should not be construed as a limitation of this invention. The specific dimensions used in this embodiment are only for illustrating the technical solution and do not limit the scope of protection of this invention.

[0024] A miniaturized broadband 180° filter coupler based on a microcoaxial transmission line includes a microcoaxial outer conductor base 900, a first microcoaxial open-circuit coupling line 100, a second microcoaxial open-circuit coupling line 200, a third microcoaxial open-circuit coupling line 300, a microcoaxial short-circuit coupling line 400, a first microcoaxial filter stub 500, a second microcoaxial filter stub 600, a through port 810, a coupling port 820, an input port 710, and an isolation port 720.

[0025] like Figure 2 As shown, the microcoaxial outer conductor base 900 includes: a microcoaxial outer conductor left arm and a microcoaxial outer conductor right arm, a microcoaxial outer conductor upper arm and a microcoaxial outer conductor lower arm, a microcoaxial outer conductor upper arm wing and a microcoaxial outer conductor lower arm wing; The left arm and right arm of the microcoaxial outer conductor are arranged relatively parallel to each other along the longitudinal direction. The upper arm and lower arm of the micro-coaxial outer conductor are arranged relatively parallel to each other in the transverse direction; The left arm, upper arm, right arm, and lower arm of the microcoaxial outer conductor are connected in sequence to form a rectangle. The upper arm of the microcoaxial outer conductor is U-shaped with a left opening, one end of which is connected to the left end of the upper arm of the microcoaxial outer conductor, and the other end is open. The lower arm of the microcoaxial outer conductor is U-shaped with a right opening. One end of the wing is connected to the right end of the lower arm of the microcoaxial outer conductor, while the other end is open. The upper arm wing and the lower arm wing of the microcoaxial outer conductor are centrally symmetrical; The microcoaxial outer conductor base has an intermediate cavity at the centerline position along its length direction. Specifically, the left arm, right arm, upper arm, and lower arm of the microcoaxial outer conductor have intermediate cavities at the centerline position along their respective length directions; the upper arm wing and lower arm wing of the microcoaxial outer conductor also have intermediate cavities at the centerline position along their respective length directions.

[0026] The input port 710 and the coupling port 820 are respectively located at the left and right corners of the upper arm of the micro coaxial outer conductor, and the through port 810 and the isolation port 720 are respectively located at the left and right corners of the lower arm of the micro coaxial outer conductor.

[0027] The isolation port of this invention has excellent isolation, preventing reflected signals from interfering with the preceding circuitry, reducing potential instability caused by reflected signals, and improving the overall efficiency and reliability of the communication system.

[0028] Furthermore, the micro-coaxial outer conductor base is made of metal, and its intermediate cavity is filled with air.

[0029] Furthermore, the third microcoaxial open-circuit coupling line 300 is placed laterally on the upper arm of the microcoaxial outer conductor, with its two ends connected to the input port 710 and the coupling port 820, respectively. The microcoaxial short-circuit coupling line 400 is placed laterally on the lower arm of the outer conductor of the microcoaxial cable, and its two ends are connected to the through port 810 and the isolation port 720 respectively. The first microcoaxial open-circuit coupling line 100 is placed longitudinally on the left arm of the outer conductor of the microcoaxial line, and its two ends are connected to the input port 710 and the through port 810, respectively. The second microcoaxial open-circuit coupling line 200 is placed longitudinally on the right arm of the outer conductor of the microcoaxial line, and its two ends are connected to the coupling port 820 and the isolation port 720 respectively. The ring structure formed by the first micro-coaxial open-circuit coupling line, the second micro-coaxial open-circuit coupling line, the third micro-coaxial open-circuit coupling line, and the micro-coaxial short-circuit coupling line achieves a 180° coupler effect over a wide frequency band, and its planar dimensions are more compact than those of traditional broadband couplers.

[0030] The first microcoaxial filter stub 500 is placed along the path of the upper arm of the microcoaxial outer conductor, with one end connected to the input port 710 and the other end open. The second microcoaxial filter stub 600 is placed along the path of the lower arm of the microcoaxial outer conductor, with one end connected to the isolation port 720 and the other end open.

[0031] The first and second microcoaxial filter stubs introduce out-of-band zeros, enhancing the out-of-band selectivity of the coupler and improving the out-of-band suppression level.

[0032] In one embodiment, the height and width of the microcoaxial outer conductor base are set to be the same, and the width of the inner wall of the intermediate cavity is 0.53 mm and the height is 0.3 mm; the height of the first microcoaxial open-circuit coupling line 100, the second microcoaxial open-circuit coupling line 200, the third microcoaxial open-circuit coupling line 300, the microcoaxial short-circuit coupling line 400, the first microcoaxial filter stub 500, and the second microcoaxial filter stub 600 are all set to 0.1 mm.

[0033] The first micro-coaxial open-circuit coupling line 100 includes two parallel transmission lines: one transmission line is connected to the input port 710 at one end and is open at the other end; the other transmission line is connected to the through port 810 at one end and is open at the other end. Support bars are evenly arranged on both sides of the first micro coaxial open-circuit coupling line 100, and the first micro coaxial open-circuit coupling line 100 is supported by the support bars at the center of its corresponding intermediate cavity. Furthermore, the first micro-coaxial open-circuit coupling line is made of metal, and the support strip is made of SU-8 photoresist; In one embodiment, the inner conductors of the two transmission lines of the first micro-coaxial open-circuit coupling line 100 are of the same size, with the length and width of the inner conductor of each transmission line being 3.16 mm and 0.04 mm, respectively, and the distance between the inner conductors of the two transmission lines being 0.02 mm. The second micro coaxial open-circuit coupling line 200 includes two parallel transmission lines: one transmission line is connected to the isolation port 720 at one end and is open at the other end; the other transmission line is connected to the coupling port 820 at one end and is open at the other end. The second micro coaxial open-circuit coupling line 200 is evenly arranged with support bars on both sides, and the second micro coaxial open-circuit coupling line 200 is supported by the support bars at the center of its corresponding intermediate cavity. Furthermore, the second micro-coaxial open-circuit coupling line is made of metal, and the support strip is made of SU-8 photoresist; In one embodiment, the inner conductors of the two transmission lines of the second micro-coaxial open-circuit coupling line 200 are of the same size, with the length and width of the inner conductor of each transmission line being 3.16 mm and 0.04 mm, respectively, and the distance between the inner conductors of the two transmission lines being 0.02 mm. The third micro-coaxial open-circuit coupling line 300 includes two parallel transmission lines: one transmission line is connected to the input port 710 at one end and is open at the other end; the other transmission line is connected to the coupling port 820 at one end and is open at the other end. The third micro-coaxial open-circuit coupling line 300 is evenly arranged with support bars on both sides, and the third micro-coaxial open-circuit coupling line 300 is supported by the support bars at the center of its corresponding intermediate cavity. Furthermore, the third micro-coaxial open-circuit coupling line is made of metal, and the support strip is made of SU-8 photoresist. In one embodiment, the inner conductors of the two transmission lines of the third micro-coaxial open-circuit coupling line 300 are of the same size, with the length and width of the inner conductor of each transmission line being 3.06 mm and 0.04 mm, respectively, and the distance between the inner conductors of the two transmission lines being 0.02 mm. The microcoaxial short-circuit coupling line 400 includes two parallel transmission lines: one transmission line is connected at one end to the isolation port 720 and at the other end to the corresponding microcoaxial outer conductor base via the grounding post 430; the other transmission line is connected at one end to the through port 810 and at the other end to the corresponding microcoaxial outer conductor base via the grounding post 430. Support bars are evenly arranged on both sides of the micro-coaxial short-circuit coupling line 400, and the micro-coaxial short-circuit coupling line 400 is supported by the support bars at the center of its corresponding intermediate cavity. Furthermore, the micro-coaxial short-circuit coupling line 400 is made of metal, and the support strip is made of SU-8 photoresist; In one embodiment, the inner conductors of the two transmission lines of the micro-coaxial short-circuit coupling line 400 are of the same size, with the length and width of the inner conductor of each transmission line being 3.06 mm and 0.03 mm, respectively, and the distance between the inner conductors of the two transmission lines being 0.02 mm; the length, width, and height of the grounding post 430 are 0.03 mm, 0.03 mm, and 0.1 mm, respectively. The first microcoaxial filter stub 500 is formed by connecting the first bent coupling line 510 and the first bent open-circuit transmission line 520. The first bent coupling line 510 is placed along the front half of the path of the upper arm wing of the microcoaxial outer conductor, and the first bent open-circuit transmission line 520 is placed along the rear half of the path of the upper arm wing of the microcoaxial outer conductor. The first bent coupling line 510 includes two bent coupling lines arranged in parallel: one end of the bent coupling line is connected to the input port 710 and the other end is open; the other bent coupling line is open at the end near the input port 710 and connected to the first bent open transmission line 520 at the end away from the input port 710. The first micro-coaxial filter stub 500 is evenly provided with support bars on both sides, and the first micro-coaxial filter stub 500 is supported by the support bars at the center of its corresponding intermediate cavity. Furthermore, the first micro-coaxial filter stub 500 is made of metal, and the support strip is made of SU-8 photoresist; At the first bent coupling line 510, the two parallel bent coupling lines have the same dimensions. The length and width of the conductor inside each bent coupling line are 3 mm and 0.02 mm, respectively, and the spacing between the conductors inside the two parallel bent coupling lines is 0.03 mm. The length and width of the first bent open-circuit transmission line 520 are 3 mm and 0.05 mm, respectively. The second microcoaxial filter stub 600 is formed by connecting the second bent coupling line 610 and the second bent open-circuit transmission line 620. The second bent coupling line 610 is placed along the first half of the path of the lower arm wing of the microcoaxial outer conductor, and the second bent open-circuit transmission line 620 is placed along the second half of the path of the lower arm wing of the microcoaxial outer conductor.

[0034] The second bent coupling line 610 includes two bent coupling lines arranged in parallel: one end of the bent coupling line is connected to the isolation port 720 and the other end is open; the other bent coupling line is open at the end near the input port 710 and connected to the second bent open transmission line 620 at the end away from the input port 710. The second micro coaxial filter stub 600 is evenly provided with support bars on both sides, and the second micro coaxial filter stub 600 is supported by the support bars at the center of its corresponding intermediate cavity. Furthermore, the second micro-coaxial filter stub 600 is made of metal, and the support strip is made of SU-8 photoresist; At the second bent coupling line 610, the two parallel bent coupling lines have the same dimensions. The length and width of the conductor inside each bent coupling line are 3 mm and 0.02 mm, respectively, and the spacing between the conductors inside the two parallel bent coupling lines is 0.03 mm. The length and width of the second bent open-circuit transmission line 620 are 3 mm and 0.05 mm, respectively. As shown in Figure 3(a), the curves in the figure represent the S-parameters of each input and output port when the input port 710 is excited; the curves in Figure 3(b) represent the S-parameters of each input and output port when the isolation port 720 is excited. Figure 4 This represents the phase difference between each output port.

[0035] In use, when the input port 710 is energized, the coupling of the miniaturized broadband 180° filter coupler based on the micro coaxial transmission line of this application is 3dB, and the phase difference between the through port 810 and the coupled port 820 is 0°; when the isolation port 720 is energized, the coupling of the miniaturized broadband 180° filter coupler based on the micro coaxial transmission line of this application is 0dB, and the phase difference between the through port 810 and the coupled port 820 is 180°.

[0036] It can be seen that the coupler achieves a coupling degree of 3dB, and the amplitude and phase difference fluctuations at the output port are minimal over a wide bandwidth.

[0037] In summary, this invention proposes a miniaturized broadband 180° filter coupler based on microcoaxial transmission lines. It achieves a 180° broadband coupler effect through a first microcoaxial open-circuit coupling line, a second microcoaxial open-circuit coupling line, a third microcoaxial open-circuit coupling line, and a microcoaxial short-circuit coupling line. The filter and 180° coupler are integrated, replacing the cascaded approach of two independent devices in traditional designs, significantly reducing the overall system's planar size. This invention utilizes microcoaxial coupling lines to construct a novel coupler, offering advantages such as miniaturization and wide bandwidth, solving problems such as narrow bandwidth, limited functionality, and large size in existing couplers.

[0038] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0039] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and these equivalent transformations all fall within the protection scope of the present invention.

Claims

1. A miniaturized broadband 180° filter coupler based on a micro coaxial transmission line, characterized in that: It includes a microcoaxial outer conductor base, a first microcoaxial open-circuit coupling line, a second microcoaxial open-circuit coupling line, a third microcoaxial open-circuit coupling line, a microcoaxial short-circuit coupling line, a first microcoaxial filter stub, a second microcoaxial filter stub, a through port, a coupling port, an input port, and an isolation port; The microcoaxial outer conductor base includes: a microcoaxial outer conductor left arm and a microcoaxial outer conductor right arm, a microcoaxial outer conductor upper arm and a microcoaxial outer conductor lower arm, a microcoaxial outer conductor upper arm wing and a microcoaxial outer conductor lower arm wing; The left arm and right arm of the microcoaxial outer conductor are arranged relatively parallel to each other along the longitudinal direction. The upper arm and lower arm of the micro-coaxial outer conductor are arranged relatively parallel to each other in the transverse direction; The left arm, upper arm, right arm, and lower arm of the microcoaxial outer conductor are connected in sequence to form a rectangle. The upper arm of the microcoaxial outer conductor is U-shaped with a left opening, one end of which is connected to the left end of the upper arm of the microcoaxial outer conductor, and the other end is open. The lower arm of the microcoaxial outer conductor is U-shaped with a right opening. One end of the wing is connected to the right end of the lower arm of the microcoaxial outer conductor, while the other end is open. The upper arm wing and the lower arm wing of the microcoaxial outer conductor are centrally symmetrical; The micro-coaxial outer conductor base has an intermediate cavity at the centerline position along its length direction; The input port and coupling port are respectively located at the left and right corners of the upper arm of the micro-coaxial outer conductor, and the through port and isolation port are respectively located at the left and right corners of the lower arm of the micro-coaxial outer conductor; The first microcoaxial open-circuit coupling line is placed longitudinally on the left arm of the outer conductor of the microcoaxial line, with its two ends connected to the input port and the through port, respectively. The second microcoaxial open-circuit coupling line is placed longitudinally on the right arm of the outer conductor of the microcoaxial line, with its two ends connected to the coupling port and the isolation port, respectively. The third microcoaxial open-circuit coupling line is placed laterally on the upper arm of the outer conductor of the microcoaxial line, with its two ends connected to the input port and the coupling port, respectively. The microcoaxial short-circuit coupling line is placed laterally on the lower arm of the outer conductor of the microcoaxial cable, with its two ends connected to the through port and the isolation port, respectively. The first microcoaxial filter stub is placed along the path of the upper arm of the outer conductor of the microcoaxial cable, with one end connected to the input port and the other end open. The second microcoaxial filter stub is placed along the path of the lower arm of the microcoaxial outer conductor, with one end connected to the isolation port and the other end open.

2. The miniaturized broadband 180° filter coupler based on a micro-coaxial transmission line according to claim 1, characterized in that: The microcoaxial outer conductor base is made of metal, and its intermediate cavity is filled with air.

3. The miniaturized broadband 180° filter coupler based on a micro-coaxial transmission line according to claim 1, characterized in that: The height and width of the microcoaxial outer conductor base are set to be the same, and the width of the inner wall of the intermediate cavity is 0.53mm and the height is 0.3mm. The height of the first microcoaxial open-circuit coupling line, the second microcoaxial open-circuit coupling line, the third microcoaxial open-circuit coupling line, the microcoaxial short-circuit coupling line, the first microcoaxial filter stub, and the second microcoaxial filter stub is set to 0.1mm.

4. The miniaturized broadband 180° filter coupler based on a micro-coaxial transmission line according to claim 1, characterized in that: The first micro-coaxial open-circuit coupling line includes two parallel transmission lines: one transmission line is connected to the input port at one end and is open at the other end; the other transmission line is connected to the through port at one end and is open at the other end. Support bars are evenly arranged on both sides of the first micro-coaxial open-circuit coupling line, and the first micro-coaxial open-circuit coupling line is supported by the support bars at the center of its corresponding intermediate cavity. The second micro-coaxial open-circuit coupling line includes two parallel transmission lines: one transmission line is connected to the isolation port at one end and is open at the other end; the other transmission line is connected to the coupling port at one end and is open at the other end. Support bars are evenly arranged on both sides of the second micro coaxial open-circuit coupling line, and the second micro coaxial open-circuit coupling line is supported by the support bars at the center of its corresponding intermediate cavity. The third micro-coaxial open-circuit coupling line includes two parallel transmission lines: one transmission line is connected to the input port at one end and is open at the other end; the other transmission line is connected to the coupling port at one end and is open at the other end. Support bars are evenly arranged on both sides of the third micro-coaxial open-circuit coupling line 300, and the third micro-coaxial open-circuit coupling line 300 is supported by the support bars at the center of its corresponding intermediate cavity.

5. The miniaturized broadband 180° filter coupler based on a micro-coaxial transmission line according to claim 1, characterized in that: The microcoaxial short-circuit coupling line includes two parallel transmission lines: one transmission line is connected to the isolation port at one end and to the corresponding microcoaxial outer conductor base through a grounding post at the other end; the other transmission line is connected to the through port at one end and to the corresponding microcoaxial outer conductor base through a grounding post at the other end. Support bars are evenly arranged on both sides of the micro-coaxial short-circuit coupling line, and the micro-coaxial short-circuit coupling line is supported by the support bars at the center of its corresponding intermediate cavity.

6. The miniaturized broadband 180° filter coupler based on a micro-coaxial transmission line according to claim 1, characterized in that: The first microcoaxial filter stub is formed by connecting a first bent coupling line and a first bent open-circuit transmission line. The first bent coupling line is placed along the front half of the path of the upper arm wing of the microcoaxial outer conductor, and the first bent open-circuit transmission line is placed along the rear half of the path of the upper arm wing of the microcoaxial outer conductor. The second microcoaxial filter stub is formed by connecting the second bent coupling line and the second bent open-circuit transmission line. The second bent coupling line is placed along the first half of the path of the lower arm wing of the outer conductor of the microcoaxial cable, and the second bent open-circuit transmission line is placed along the second half of the path of the lower arm wing of the outer conductor of the microcoaxial cable.

7. The miniaturized broadband 180° filter coupler based on a micro-coaxial transmission line according to claim 6, characterized in that: The first bent coupling line includes two bent coupling lines arranged in parallel: one end of the bent coupling line is connected to the input port and the other end is open; the other bent coupling line is open at the end closer to the input port and connected to the first bent open transmission line at the end farther from the input port. The first micro-coaxial filter stub is evenly arranged with support bars on both sides, and the first micro-coaxial filter stub is supported by the support bars at the center of its corresponding intermediate cavity. The second bent coupling line includes two bent coupling lines arranged in parallel: one end of the bent coupling line is connected to the isolation port and the other end is open; the other bent coupling line is open at the end near the input port and connected to the second bent open transmission line at the end away from the input port. The second micro-coaxial filter stub is evenly supported by support bars on both sides, and the second micro-coaxial filter stub is supported by the support bars at the center of its corresponding intermediate cavity.

8. The miniaturized broadband 180° filter coupler based on a micro-coaxial transmission line according to claim 1, characterized in that: The first microcoaxial open-circuit coupling line, the second microcoaxial open-circuit coupling line, the third microcoaxial open-circuit coupling line, the microcoaxial short-circuit coupling line, the first microcoaxial filter stub, and the second microcoaxial filter stub are made of metal; the support strip is made of SU-8 photoresist.

9. The miniaturized broadband 180° filter coupler based on a micro-coaxial transmission line according to claim 4, 5, or 7, characterized in that: The inner conductors of the two transmission lines of the first micro-coaxial open-circuit coupling line have the same dimensions. The length and width of the inner conductor of each transmission line are 3.16 mm and 0.04 mm, respectively, and the distance between the inner conductors of the two transmission lines is 0.02 mm. The inner conductors of the two transmission lines of the second micro-coaxial open-circuit coupling line have the same dimensions. The length and width of the inner conductor of each transmission line are 3.16 mm and 0.04 mm, respectively, and the distance between the inner conductors of the two transmission lines is 0.02 mm. The inner conductors of the two transmission lines of the third micro-coaxial open-circuit coupling line have the same dimensions. The length and width of the inner conductor of each transmission line are 3.06 mm and 0.04 mm, respectively, and the distance between the inner conductors of the two transmission lines is 0.02 mm. The inner conductors of the two transmission lines of the micro-coaxial short-circuit coupling line have the same dimensions. The length and width of the inner conductor of each transmission line are 3.06 mm and 0.03 mm, respectively, and the distance between the inner conductors of the two transmission lines is 0.02 mm. The length, width and height of the grounding post are 0.03 mm, 0.03 mm and 0.1 mm, respectively.

10. The miniaturized broadband 180° filter coupler based on a micro-coaxial transmission line according to claim 9, characterized in that: At the first bend coupling line, the two parallel bend coupling lines have the same dimensions. The length and width of the conductor inside each bend coupling line are 3mm and 0.02mm, respectively, and the spacing between the conductors inside the two parallel bend coupling lines is 0.03mm. The length and width of the first bend open-circuit transmission line are 3mm and 0.05mm, respectively. The two parallel bent coupling lines at the second bend coupling line have the same dimensions. The length and width of the conductor inside each bent coupling line are 3mm and 0.02mm, respectively, and the spacing between the conductors inside the two parallel bent coupling lines is 0.03mm. The length and width of the second bend open-circuit transmission line are 3mm and 0.05mm, respectively.

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