Capacitor loading low-frequency miniature bridge

Abstract

The invention relates to a capacitor loading low-frequency micro bridge, which comprises a bridge structure main body formed by stacking a plurality of layers of dielectric substrates, and a coupling lead, a through hole and a capacitor are arranged in the bridge structure main body. According to the functional structure, the bridge can be divided into a top grounding layer, two coupling wires which are mutually coupled, through holes which are communicated with the wires of different levels, capacitors which are connected with the wires through the through holes, and six external ports which are arranged on the outer surface layer. The capacitor-loaded low-frequency miniature bridge has the characteristics of small size, light weight and excellent performance. The size of the capacitor loading low-frequency miniature bridge is only 3.2 * 2.5 * 1.125 mm, and the requirement for miniaturization of modern communication equipment is met. The capacitance loading low-frequency miniature bridge has the advantages of being small in size, light in weight, low in cost and suitable for mass production.

Description

Technical Field

[0001] The invention relates to the technical field of low-frequency micro-bridges, and in particular to a capacitor-loaded low-frequency micro-bridge. Background Art

[0002] Nowadays, in the era of the great prosperity of electronic communication equipment, the development of various equipment has entered the stage of miniaturization and micro-miniaturization. At the same time, corresponding miniaturization requirements are also put forward for various related devices. As one of the commonly used passive components, the bridge must also conform to the development requirements. The general low-frequency bridge adopts a series multi-layer stacking structure, which occupies a large area, is thick, and has a large overall volume, which cannot meet the current needs of miniaturization development. Summary of the invention

[0003] In order to solve the problem of large volume of low-frequency bridges, the purpose of the present invention is to provide a capacitor-loaded low-frequency micro-bridge, which meets the development demand of device miniaturization through capacitor loading technology and structural optimization.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A capacitor-loaded low-frequency micro-bridge includes a bridge structure body formed by stacking multiple layers of dielectric substrates, a wire part, a through hole and a loading capacitor arranged inside the bridge structure body, and an external port arranged on the outer surface of the bridge structure body; the top layer of the bridge structure body is a grounding layer; the wire part includes twenty layers of wires; wherein the first and second layers of the bridge structure body are each provided with a wire, and each layer of other structure body layers is provided with two wires; the twenty layers of wires and through holes are interconnected to form a main body coupling wire; the through hole is used to connect wires of different levels; the loading capacitor is connected to the corresponding wire through the through hole; the external port includes an input terminal 1, a grounding terminal 2, an isolation terminal 3, an output terminal 4, a grounding terminal 5 and an output terminal 6. The number of wire layers is different from the number of dielectric substrate layers, and the two are not one-to-one corresponding. The number of layers of the dielectric substrate with wires is 20, and the dielectric substrate has a total of 25 layers. The first and second layers of wires are not one wire. Functionally, there are only two wires in total. The wires on the 1st, 3rd, 5th, 7th, 9th, 11th, 13th, 15th, 17th, and 19th layers are connected and form one wire; the wires on the 2nd, 4th, 6th, 8th, 10th, 12th, 14th, 16th, 18th, and 20th layers are connected and form one wire.

[0006] The top layer of the bridge structure body is a grounding layer, and the grounding layer is connected to the grounding terminal 2 and the grounding terminal 5; the wires on the bridge structure body are connected in a layer-by-layer manner, so as to connect to the twentieth layer; a wire is provided in the middle part of the grounding layer, and the wire is connected to the two wires on the third layer of the bridge structure body through a through hole; a wire on the second layer of the bridge structure body is connected to the two wires on the fourth layer of the bridge structure body through a through hole; the third to twentieth layers of the bridge structure body are interconnected by two wires on each layer in a layer-by-layer manner; the wires on the third layer of the bridge structure body The two wires are connected to the two wires on the fifth layer of the bridge structure body through a through hole; the two wires on the fourth layer of the bridge structure body are connected to the two wires on the sixth layer of the bridge structure body through a through hole; the bridge structure body extends downward with the third and fourth layers as templates; one end of the two wires on the nineteenth layer of the bridge structure body is connected to the isolation port three and the output port six, and the other end is connected to the two wires on the seventeenth layer through a through hole; one end of the two wires on the twentieth layer of the bridge structure body is connected to the input port one and the output port four, and the other end is connected to the two wires on the eighteenth layer through a through hole.

[0007] As a further improvement of the above technical solution, the isolation port three and the output port six in the seventh layer of the bridge structure main body each extend a wire from the port along the main body coupling wire on its outer side as the port extension wire of the seventh layer. The input port one and the output port four in the eighth layer of the bridge structure main body each extend a wire from the port along the spiral structure wire on its outer side as the port extension wire of the eighth layer. The isolation port three and the output port six in the ninth layer of the bridge structure main body each extend a wire from the port along the spiral structure wire on its outer side as the port extension wire of the ninth layer. The input port one and the output port four in the tenth layer of the bridge structure main body each extend a wire from the port along the spiral structure wire on its outer side as the port extension wire of the tenth layer. The isolation port three and the output port six in the eleventh layer of the bridge structure main body each extend a wire from the port along the spiral structure wire on its outer side as the port extension wire of the eleventh layer. The input port one and the output port four in the twelfth layer of the bridge structure main body each extend a wire from the port along the spiral structure wire on its outer side as the port extension wire of the twelfth layer. The isolation port 3 and the output port 6 in the thirteenth layer of the bridge structure main body each extend a wire from the port along the spiral structure wire on the outer side thereof as the port extension wire of the thirteenth layer. The input port 1 and the output port 4 in the fourteenth layer of the bridge structure main body each extend a wire from the port along the spiral structure wire on the outer side thereof as the port extension wire of the fourteenth layer. The port extension wires are coupled to each other.

[0008] As a further improvement of the above technical solution, the input port one and the output port four form a coupling line, and the isolation port three and the output port six form a coupling line. The output amplitudes of the two coupling lines are equal and the phase difference is 90 degrees.

[0009] As a further improvement of the above technical solution, two loading capacitors are provided on the main body of the bridge structure; each loading capacitor is an embedded capacitor and adopts a VIC structure; the two ends of the capacitor are connected to the ground terminal through a through hole, and the through hole is connected to the wire; the two coupling lines of the main body of the bridge structure are both connected to a grounding capacitor.

[0010] As a further improvement of the above technical solution, the main coupling wire is divided into two left and right parts from the third layer of the bridge structure body downwards, and the two parts are arranged and wired in a spiral manner at the same time. Upward or downward through holes are provided at both ends of each layer of the wire, and the wires of different layers are connected to each other through the through holes, and the coupling wires of the double helix structure are connected in the third to twentieth layers.

[0011] As a further improvement of the above technical solution, the loading capacitor includes part A1, part A2, part A3, part A4, part A5, part A6, part A7, part A8, part A9, part A10, part A11, part A12, part A13, part B1, part B2, part B3, part B4, part B5, part B6, part B7, part B8, part B9, part B10 and part B11.

[0012] The A1 part is connected to the second ground terminal, the A2 part is connected to the through hole C1, the A3 part is connected to the second ground terminal, the A4 part is connected to the through hole C1, the A5 part is connected to the second ground terminal, the A6 part is connected to the through hole C1, the A7 part is connected to the second ground terminal, the A8 part is connected to the through hole C1, the A9 part is connected to the second ground terminal, the A10 part is connected to the through hole C1, the A11 part is connected to the through hole C1, the A12 part is connected to the second ground terminal, and the A13 part is connected to the through hole C1; the A1 part, the A2 part, the A3 part, the A4 part, the A5 part, the A6 part, the A7 part, the A8 part, the A9 part, the A10 part, the A11 part, the A12 part, and the A13 part are connected in parallel, and are connected to the second layer of the bridge structure body through the through hole C1, and are connected between the wire and the ground as a grounding capacitor.

[0013] The B1 part of the loading capacitor is connected to the through hole C2, the B2 part is connected to the ground terminal five, the B3 part is connected to the through hole C2, the B4 part is connected to the ground terminal five, the B5 part is connected to the through hole C2, the B6 part is connected to the ground terminal five, the B7 part is connected to the through hole C2, the B8 part is connected to the ground terminal five, the B9 part is connected to the through hole C2, the B10 part is connected to the ground terminal five, and the B11 part is connected to the through hole C2. The B1 part, the B2 part, the B3 part, the B4 part, the B5 part, the B6 part, the B7 part, the B8 part, the B9 part, the B10 part and the B11 part are connected to each other in parallel, and are connected to the first layer of the bridge structure body through the through hole C2, and are connected between the wire and the ground as a grounding capacitor. Only the through hole C1 and the through hole C2 are used as the capacitor part, and the capacitors are connected through multiple layers and connected to the wires.

[0014] As a further improvement of the above technical solution, the dielectric substrate adopts a ceramic substrate, and the bridge structure body adopts LTCC low temperature co-firing technology to achieve the integration of multi-layer dielectric substrates.

[0015] Compared with the prior art, the advantages of the present invention are:

[0016] (1) The capacitor-loaded low-frequency micro-bridge described in the present invention has a size of only 3.2X2.5X1.125mm, which meets the needs of miniaturization of modern communication equipment. The capacitor-loaded low-frequency micro-bridge described in the present invention has the characteristics of small size, light weight, low cost, and suitable for mass production. The traditional LTCC bridge is mainly composed of two wires, and the index setting of the bridge is completed by the two wires. The present invention adds a capacitor part and connects the two capacitors with the two wires. Not only can the bridge index be adjusted by the wire, but also the bridge index can be adjusted by the capacitor. The traditional wire distribution adopts a single spiral structure from bottom to top. The internal wire distribution in the present invention removes the first and second layers, and adopts a single spiral structure to be split into two spiral structures, and then the two structures are connected by wires, forming a quasi-arch bridge structure composed of two spiral structures as a whole. The signal enters from the input port one and spirals upward along the wire, reaches the second layer, is connected by the wire, and then enters another spiral structure wire, and then transmits from top to bottom, and finally outputs through the output port four. The wires of the traditional bridge structure are only two inseparable wires, and the indicators of the bridge are changed by adjusting the wire length, wire width and distribution. On the basis of the tradition, the present invention additionally adopts multiple segments of wires and utilizes the coupling principle of microstrip lines to form an external extension with the original two wires, so as to more effectively utilize the limited space area, reduce its operating frequency, and ensure that the phase is about 90°.

[0017] (2) The loading capacitor technology adopted by the present invention mainly solves the problem of large volume of low-frequency bridge. According to the microstrip line principle and its formula, it can be concluded that the length of the microstrip line will continue to increase as the operating frequency of the bridge decreases. The increasing line length first brings about the problem of increased volume of the bridge, accompanied by a series of problems such as increased coupling, increased isolation, and increased insertion loss. The use of loading capacitor technology can reduce the volume by nearly half, while reducing the coupling and reducing the isolation effect. The change in the distribution of the wire structure reduces the large coupling originally caused by the wire distribution, and reduces other clutter interference. The external extension of the wire further improves the wire on the basis of the wire structure distribution, increases the wire length without changing the original wire length, makes full use of the limited space, reduces its operating frequency, and ensures that the phase is around 90°.

[0018] (3) The capacitor-loaded low-frequency micro-bridge described in the present invention is mainly suitable for low-frequency working range and realizes miniaturization in the low-frequency range. In the traditional bridge design, two wires are coupled to meet the design requirements. The present invention proposes a method of loading capacitors to achieve miniaturization of the bridge volume, reduce insertion loss, optimize isolation, and optimize the internal structure to further improve the volume of the low-frequency bridge. The external extension of the wire reduces its working frequency and ensures that the phase is stable at about 90°. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the capacitor-loaded low-frequency micro-bridge in the present invention;

[0020] Figure 2 Schematic diagram of the outer surface port of the capacitor-loaded low-frequency micro-bridge in the present invention;

[0021] Figure 3 It is a structural schematic diagram of the grounding layer in the present invention;

[0022] Figure 4 This is a schematic diagram of the structure of the main coupling wire part of the present invention Figure 1 ;

[0023] Figure 5 The structure of the coupling wire part in the present invention is shown in FIG. Figure 2 ;

[0024] Figure 6 The structure of the coupling wire part in the present invention is shown in FIG. Figure 3 ;

[0025] Figure 7 The structure of the coupling wire part in the present invention is shown in FIG. Figure 4 ;

[0026] Figure 8It is a schematic diagram of the structure of the port extension wire in the present invention;

[0027] Fig. 9 It is a schematic diagram of the capacitor structure in the present invention;

[0028] Fig.10 This is a diagram of the S-parameter simulation results of the capacitor-loaded low-frequency micro-bridge in the present invention;

[0029] Fig.11 This is a phase simulation result diagram of the capacitor-loaded low-frequency micro-bridge in the present invention.

[0030] Fig.12 This is a diagram of the actual experimental results of the capacitor-loaded low-frequency micro-bridge in the present invention.

[0031] in:

[0032] 1. The first layer of wires, 2. The second layer of wires, 3. The third layer of wires, 4. The fourth layer of wires, 5. The fifth layer of wires, 6. The sixth layer of wires, 7. The seventh layer of wires, 8. The eighth layer of wires, 9. The ninth layer of wires, 10. The tenth layer of wires, 11. The eleventh layer of wires, 12. The twelfth layer of wires, 13. The thirteenth layer of wires, 14. The fourteenth layer of wires, 15. The fifteenth layer of wires, 16. The sixteenth layer of wires, 17. The seventeenth layer of wires, 18. The eighteenth layer of wires, 19. The nineteenth layer of wires, 20. The twentieth layer of wires; 21. Grounding capacitors, 22. Main body coupling wires, 23. External extension wires; D1-D8, E1-E8 are external extension wires; A1-A13, B1-B11 are grounding capacitors, and C1 and C2 are capacitor connecting holes. DETAILED DESCRIPTION

[0033] The present invention will be further described below in conjunction with the accompanying drawings:

[0034] like Figure 1 A capacitor-loaded low-frequency micro-bridge is shown, and the capacitor-loaded low-frequency micro-bridge includes a bridge structure body composed of a stack of multiple layers of dielectric substrates, as well as multiple layers of wires, through holes, and capacitors. The main structure of the capacitor-loaded low-frequency micro-bridge described in this embodiment is mainly a stacked structure composed of 25 layers of dielectric substrates, and LTCC low-temperature co-firing technology is used. The dielectric substrate is a ceramic substrate.

[0035] The capacitor-loaded low-frequency microbridge described in the present invention can be divided into the following according to the functional structure: a top ground layer, two mutually coupled coupling wires, through holes connecting wires of different layers, capacitors connected to the wires through the through holes, and six external ports on the outer surface. The number of wire layers is 20, except for the first and second layers, which each have one wire for connection, and the other layers each have two wires, which are connected to other layers through through holes to form two spiral coupling wires. The two spirals form two coupling wires through the connection of the first and second layers. The two wires of each layer are separated into left and right, like two spirals circling.

[0036] In this embodiment, the wires include twenty layers. The top layer of the wires, i.e., the first layer, is a grounding layer directly connected to two grounding ports. The middle part of the same layer as the grounding layer has a wire connected to two coupling wires of the third layer through a through hole. The second layer has a wire connected to two coupling wires of the fourth layer through a through hole. The two coupling wires of the third layer are connected to the two coupling wires of the fifth layer through a through hole. The two coupling wires of the fourth layer are connected to the two coupling wires of the sixth layer through a through hole. The wires are connected in a layer-by-layer manner, thereby connecting to the twentieth layer. Among them, the seventh layer input port 1 and output port 4 lead out a wire along the periphery of the coupling wire, the eighth layer isolation port 3 and output port 6 lead out a wire along the periphery of the coupling wire, the ninth layer input port 1 and output port 4 lead out a wire along the periphery of the coupling wire, the tenth layer isolation port 3 and output port 6 lead out a wire along the periphery of the coupling wire, and the same is true for the fourteenth layer. The coupling wire of the nineteenth layer is connected to the coupling wire of the seventeenth layer through a through hole, and is connected to the isolation port three and the output port four through an interconnecting wire. The coupling wire of the twentieth layer is connected to the coupling wire of the eighteenth layer through a through hole, and is connected to the input port one and the output port four through an interconnection wire.

[0037] In the capacitor-loaded low-frequency micro-bridge of the present invention, the loading capacitor is composed of two grounded capacitors, and the capacitor is an embedded capacitor, which adopts a VIC structure, which is not only better in Q value and SRF, but also has the advantage of small occupied area. The VIC structure is a multilayer structure, which connects the two ends of the capacitor to the ground terminal through a through hole, and the through hole is connected to the wire at the same time. Since there are two coupling wires, each coupling wire has a capacitor connected, so there are two capacitors.

[0038] like Figure 2 As shown, the capacitor-loaded low-frequency micro-bridge has six ports on the outer surface, namely, input port one, ground port two, isolation port three, output port four, ground port five and output port six. The input port one and output port four form a coupling line, the isolation port three and output port six form a coupling line, and the output amplitudes of the two coupling lines are equal and the phase difference is 90 degrees.

[0039] like Figure 3 As shown, the top ground layer and coupling wires are deployed on the first layer. The ground layer and the coupling wires are combined into one layer, which not only improves the performance but also improves the space utilization. The top ground layer is connected to two ground ports.

[0040] from Figures 4 to 7 It can be seen that the detailed disassembly process of the coupling wire and the through-hole composition is that the coupling wire is divided into two parts, left and right, from the third layer downwards. These two parts are arranged in a spiral manner at the same time, with through-holes at both ends of each layer of wires, either upward or downward. The wires of different layers are interconnected through the through-holes, and the main coupling wires of the double helix structure are connected in the third to the twentieth layers. Figure 7 One end of the two wires in the 20th layer connects input port 1 and output port 4, and the other end connects to the two wires in the 18th layer through a through hole. One end of the two wires in the 19th layer connects isolation port 3 and output port 6, and the other end connects to the two wires in the 17th layer through a through hole. The two wires in the 18th layer are connected to the two wires in the 16th layer through a through hole. The two wires in the 17th layer are connected to the two wires in the 15th layer through a through hole. The two coupling lines in the third to 20th layers are connected to each other one layer at a time. Figure 4 There is only one wire in the second layer, and the through holes at both ends of the wire are connected to the left and right wires of the fourth layer, connecting the input port one with the output port four to form a coupling line. There is only one wire in the first layer, and the through holes at both ends of the wire are connected to the left and right wires of the third layer, connecting the isolation port three with the output port six to form a coupling line.

[0041] Figure 8 The D1-D8 and E1-E8 shown are port extension wires. In the seventh layer of the wires, the isolation port three and the output port six each extend a wire from the port along the spiral structure wire on the outer side thereof; in the eighth layer, the input port one and the output port four each extend a wire from the port along the spiral structure wire on the outer side thereof; in the ninth layer, the isolation port three and the output port six each extend a wire from the port along the spiral structure wire on the outer side thereof; in the tenth layer, the input port one and the output port four each extend a wire from the port along the spiral structure wire on the outer side thereof; in the eleventh layer, the isolation port three and the output port four each extend a wire from the port along the spiral structure wire on the outer side thereof; Output port six each extends a wire from the port along the spiral structure wire on its outer side; in the twelfth layer, input port one and output port four each extend a wire from the port along the spiral structure wire on its outer side; in the thirteenth layer, isolation port three and output port six each extend a wire from the port along the spiral structure wire on its outer side; in the fourteenth layer, input port one and output port four each extend a wire from the port along the spiral structure wire on its outer side; these port extension wires are coupled to each other, and are coupled at the same time under the influence of the spiral structure wire in the middle, which has the effect of increasing the overall wire length.

[0042] Fig. 9 This is a schematic diagram of the capacitor part of the capacitor-loaded low-frequency microbridge, such as Fig. 9 As shown, the A1 capacitor part is connected to the ground port, the A2 capacitor part is connected to the through hole C1, the A3 capacitor part is connected to the ground port, the A4 capacitor part is connected to the through hole C1, the A5 capacitor part is connected to the ground port, the A6 capacitor part is connected to the through hole C1, the A7 capacitor part is connected to the ground port, the A8 capacitor part is connected to the through hole C1, the A9 capacitor part is connected to the ground port, the A10 capacitor part is connected to the through hole C1, the A11 capacitor part is connected to the through hole C1, the A12 capacitor part is connected to the ground port, and the A13 capacitor part is connected to the through hole C1. These multiple capacitors are connected in parallel to increase the capacitance as a whole, and are connected to the second layer through the through hole C1, and are connected between the wire and the ground as a grounding capacitor. The B1 capacitor part is connected to the through hole C2, the B2 capacitor part is connected to the ground port, the B3 capacitor part is connected to the through hole C2, the B4 capacitor part is connected to the ground port, the B5 capacitor part is connected to the through hole C2, the B6 capacitor part is connected to the ground port, the B7 capacitor part is connected to the through hole C2, the B8 capacitor part is connected to the ground port, the B9 capacitor part is connected to the through hole C2, the B10 capacitor part is connected to the ground port, and the B11 capacitor part is connected to the through hole C2. They are connected to each other in parallel and connected to the No. 1 layer through the through hole C2, and are connected between the wire and the ground as a grounding capacitor.

[0043] The design principle of the capacitor-loaded low-frequency microbridge described in the present invention is:

[0044] Capacitor-loaded low-frequency microbridge, since the length of the coupling wire of the bridge is one quarter of the wavelength, that is, Among them, l is the length of the wire, c is the propagation speed of light in air, ε r is the relative dielectric constant of the dielectric substrate, and f0 is the working center frequency of the bridge. It can be seen that the low-frequency bridge has a longer line length than other general bridges, and the longer line length directly leads to the disadvantage of large volume. There are three ways to overcome this disadvantage. The first is to use a dielectric substrate with a high relative dielectric constant as the material, the second is to optimize the internal wire structure, and the third is to load capacitance on the wire.

[0045] For the above problems, the present invention reduces the volume of the low-frequency bridge by using a method of loading capacitors, one end of the capacitor is connected to the coupling wire through a through hole, and the other end of the capacitor is directly connected to the ground port. In order to further reduce the volume, the present invention optimizes the internal structure of the bridge. The layout of the wire is structurally changed, and the wire is divided into two parts for wiring, wherein both parts are wired in a double spiral ascending manner, and finally the wire uses a wire in the first layer and the second layer to connect the two parts of the two coupling wires, so that the two ends of the two coupling wires are connected. In addition, a wire is led out along the periphery of the coupling wire at the seventh layer input port and output port, a wire is led out along the periphery of the coupling wire at the eighth layer isolation port and output port, a wire is led out along the periphery of the coupling wire at the ninth layer input port and output port, and a wire is led out along the periphery of the coupling wire at the tenth layer isolation port and output port, and wires are added alternately until the fourteenth layer is completed.

[0046] like Figure 10-12 As shown, after testing, the capacitor-loaded low-frequency micro-bridge described in the present invention has an insertion loss of less than 1dB, a return loss of less than -23dB, an isolation lower than -20dB, and a phase of 90°±3° within the working range of the low-frequency state, and has a relatively superior low-frequency bridge performance.

[0047] The above-described embodiments are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the scope of protection determined by the claims of the present invention.

Claims

1. A capacitor-loaded low-frequency microbridge, characterized in that: The capacitor-loaded low-frequency micro bridge comprises a bridge structure body formed by stacking multiple layers of dielectric substrates, a wire part, a through hole and a loading capacitor arranged inside the bridge structure body, and an external port arranged on the outer surface of the bridge structure body; the top layer of the bridge structure body is a ground layer; the wire part comprises twenty layers of wires; wherein the first layer and the second layer of the bridge structure body are each provided with a wire, and each layer of other structure body layers is provided with two wires; the twenty layers of wires and through holes are interconnected to form a main body coupling wire; the through hole is used to connect wires of different levels; the loading capacitor is connected to the corresponding wire through the through hole; the external port comprises an input terminal one, a ground terminal two, an isolation terminal three, an output terminal four, a ground terminal five and an output terminal six; The top layer of the bridge structure body is a grounding layer, and the grounding layer is connected to the grounding terminal 2 and the grounding terminal 5; the wires on the bridge structure body are connected in a layer-by-layer manner, so as to connect to the twentieth layer; a wire is provided in the middle part of the grounding layer, and the wire is connected to the two wires on the third layer of the bridge structure body through a through hole; a wire on the second layer of the bridge structure body is connected to the two wires on the fourth layer of the bridge structure body through a through hole; the third to twentieth layers of the bridge structure body are interconnected by two wires on each layer in a layer-by-layer manner; the wires on the third layer of the bridge structure body The two wires are connected to the two wires on the fifth layer of the bridge structure body through a through hole; the two wires on the fourth layer of the bridge structure body are connected to the two wires on the sixth layer of the bridge structure body through a through hole; the bridge structure body extends downward with the third and fourth layers as templates; one end of the two wires on the nineteenth layer of the bridge structure body is connected to the isolation port three and the output port six, and the other end is connected to the two wires on the seventeenth layer through a through hole; one end of the two wires on the twentieth layer of the bridge structure body is connected to the input port one and the output port four, and the other end is connected to the two wires on the eighteenth layer through a through hole.

2. The capacitor-loaded low-frequency microbridge according to claim 1, characterized in that: The isolation port 3 and the output port 6 in the seventh layer of the bridge structure body each extend a wire from the port along the main body coupling wire on the outer side thereof as a port extension wire of the seventh layer; The input port 1 and the output port 4 in the eighth layer of the bridge structure main body each extend a wire from the port along the spiral structure wire on the outer side thereof as a port extension wire of the eighth layer; The isolation port 3 and the output port 6 in the ninth layer of the bridge structure main body each extend a wire from the port along the spiral structure wire on the outer side thereof as a port extension wire of the ninth layer; The input port 1 and the output port 4 in the tenth layer of the bridge structure main body each extend a wire from the port along the spiral structure wire on the outer side thereof as a port extension wire of the tenth layer; The isolation port 3 and the output port 6 in the eleventh layer of the bridge structure body each extend a wire from the port along the spiral structure wire on the outer side thereof as a port extension wire of the eleventh layer; The input port 1 and the output port 4 in the twelfth layer of the bridge structure body each extend a wire from the port along the spiral structure wire on the outer side thereof as a port extension wire of the twelfth layer; The isolation port 3 and the output port 6 in the thirteenth layer of the bridge structure main body each have a wire extending from the port along the spiral structure wire on the outer side thereof as a port extension wire of the thirteenth layer; The input port 1 and the output port 4 in the fourteenth layer of the bridge structure main body each extend a wire from the port along the spiral structure wire on the outer side thereof as a port extension wire of the fourteenth layer; The extension wires of each port are coupled to each other.

3. The capacitor-loaded low-frequency microbridge according to claim 1, characterized in that: The input port 1 and the output port 4 form a coupling line, and the isolation port 3 and the output port 6 form a coupling line. The output amplitudes of the two coupling lines are equal and the phase difference is 90 degrees.

4. The capacitor-loaded low-frequency microbridge according to claim 1, characterized in that: There are two loading capacitors on the main body of the bridge structure; each loading capacitor is an embedded capacitor and adopts a VIC structure; the two ends of the capacitor are connected to the ground terminal through a through hole, and the through hole is connected to the wire; the two coupling lines of the main body of the bridge structure are both connected to a grounding capacitor.

5. The capacitor-loaded low-frequency microbridge according to claim 1, characterized in that: The main coupling wire is divided into two left and right parts from the third layer of the bridge structure body downwards. The two parts are arranged and wired in a spiral manner at the same time. Upward or downward through holes are provided at both ends of each layer of the wire. The wires of different layers are connected to each other through the through holes, and the coupling wires of the double helix structure are connected in the third to twentieth layers.

6. The capacitor-loaded low-frequency microbridge according to claim 4, characterized in that: The loading capacitor includes part A1, part A2, part A3, part A4, part A5, part A6, part A7, part A8, part A9, part A10, part A11, part A12, part A13, part B1, part B2, part B3, part B4, part B5, part B6, part B7, part B8, part B9, part B10 and part B11; The A1 part is connected to the second ground terminal, the A2 part is connected to the through hole C1, the A3 part is connected to the second ground terminal, the A4 part is connected to the through hole C1, the A5 part is connected to the second ground terminal, the A6 part is connected to the through hole C1, the A7 part is connected to the second ground terminal, the A8 part is connected to the through hole C1, the A9 part is connected to the second ground terminal, the A10 part is connected to the through hole C1, the A11 part is connected to the through hole C1, the A12 part is connected to the second ground terminal, and the A13 part is connected to the through hole C1; the A1 part, the A2 part, the A3 part, the A4 part, the A5 part, the A6 part, the A7 part, the A8 part, the A9 part, the A10 part, the A11 part, the A12 part, and the A13 part are connected in parallel, and are connected to the second layer of the bridge structure body through the through hole C1, and are connected between the wire and the ground as a grounding capacitor; Part B1 of the loading capacitor is connected to through hole C2, part B2 is connected to ground terminal five, part B3 is connected to through hole C2, part B4 is connected to ground terminal five, part B5 is connected to through hole C2, part B6 is connected to ground terminal five, part B7 is connected to through hole C2, part B8 is connected to ground terminal five, part B9 is connected to through hole C2, part B10 is connected to ground terminal five, and part B11 is connected to through hole C2. Part B1, part B2, part B3, part B4, part B5, part B6, part B7, part B8, part B9, part B10 and part B11 are connected to each other in parallel, and are connected to layer No. 1 of the bridge structure body through through hole C2, and are connected between the wire and the ground as a grounding capacitor.

7. The capacitor-loaded low-frequency microbridge according to claim 1, characterized in that: The dielectric substrate is a ceramic substrate, and the bridge structure body adopts LTCC low temperature co-firing technology to achieve the integration of multi-layer dielectric substrates.

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