Double-layer microstrip structure electric bridge

Abstract

This utility model relates to the field of passive device technology, and in particular to a double-layer microstrip bridge structure, comprising a dielectric substrate, microstrip line modules, and a ground layer. At least one set of microstrip line modules is provided. One end of the first strip is connected to the input port, the other end of the first strip is electrically connected to one end of the third strip, and the other end of the third strip is connected to a through port. One end of the second strip is connected to an isolation port, the other end of the second strip is electrically connected to one end of the fourth strip, and the other end of the fourth strip is connected to a coupling port. Multiple sawtooths are provided on opposite sides between adjacent strips. By adjusting the sawtooth gap and the number of sawtooths on each strip, the coupling degree within the 698-960MHz frequency band can be varied between 6-13dB. By adjusting the width and length of each strip, the impedance matching and phase characteristics of the bridge can be adjusted, resulting in a VSWR ≤ 1.11 and ISO ≤ -27dB within the 698-960MHz frequency band. The bridge is simple and convenient to debug, and has lower costs.

Description

Technical Field

[0001] This utility model relates to the field of passive device technology, and in particular to a double-layer microstrip structure bridge. Background Technology

[0002] A bridge is a four-port passive device that performs power distribution and phase adjustment. It boasts excellent broadband performance, high isolation, precise orthogonality, good amplitude balance, and power handling capabilities, making it widely used in the field of communication technology. Currently, the industry commonly uses double-layer microstrip bridges and cavity suspension bridges. With the rapid development of wireless technology, green antennas have become the mainstream antennas for domestic operators, and bridges play a crucial role in adjusting the horizontal plane bandwidth of the 703-803MHz / 885-960MHz frequency bands. Cavity suspension bridges are very expensive, while ordinary microstrip bridges are difficult to debug and have poor performance due to the different horizontal plane bandwidth requirements of the 703-803MHz / 885-960MHz frequency bands. Utility Model Content

[0003] In order to address the technical deficiencies mentioned in the background art, the purpose of this utility model is to provide a double-layer microstrip structure bridge.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A dual-layer microstrip bridge structure includes a dielectric substrate, microstrip line modules disposed on one side of the dielectric substrate, and a ground layer disposed on the other side of the dielectric substrate. At least one set of microstrip line modules is provided, each module including a first, second, third, and fourth microstrip line arranged in parallel, an input port and a through port disposed at one end of the dielectric substrate, and an isolation port and a coupling port disposed at the other end of the dielectric substrate. One end of the first microstrip line is connected to the input port, and the other end of the first microstrip line is electrically connected to one end of the third microstrip line, and the other end of the third microstrip line is connected to the through port. One end of the second microstrip line is connected to the isolation port, and the other end of the second microstrip line is electrically connected to one end of the fourth microstrip line, and the other end of the fourth microstrip line is connected to the coupling port. Multiple serrations are sequentially arranged along the length of each adjacent microstrip line on opposite sides.

[0006] By adopting the above technical solution, the first, second, third, and fourth strip lines are all equipped with serrations. The coupling degree within the 698-960MHz frequency band can be varied between 6-13dB by adjusting the serration gap of each strip line. The amplitude slope can be adjusted by changing the number of serrations on each strip line, and the impedance matching and phase characteristics of the bridge can be adjusted by changing the width and length of each strip line. This results in a VSWR ≤ 1.11 and ISO ≤ -27dB within the 698-960MHz frequency band, making debugging simple and convenient, more efficient, and less costly. This application can meet the requirements of different horizontal wavewidths in the 703-803MHz / 885-960MHz frequency bands, offering strong compatibility and higher performance. Furthermore, the input port and through port are located at the same end of the dielectric substrate, making cable routing more convenient and reducing the occupied area.

[0007] Furthermore, the first and fourth strips have the same structure and are both configured as straight-line sawtooth structures, and the second and third strips have the same structure. The first, fourth, second, and third strips are rotate symmetrical about 180 degrees with respect to the center of the area they enclose, resulting in a compact structure that is easy to process and assemble, and has a low cost.

[0008] Furthermore, the second stripline includes a first straight segment and a first bent segment. The first straight segment and the first stripline are located on the same horizontal line, and the first bent segment is disposed on one side of the first stripline. One end of the first bent segment is connected to the first straight segment, and the other end of the first bent segment is bent so that both ends of the first bent segment are parallel to the first stripline. The third stripline includes a second straight segment and a second bent segment. The second straight segment is disposed on the side of the first bent segment away from the first stripline, and the second straight segment and the fourth stripline are located on the same horizontal line. The second bent segment is disposed between the first straight segment and the fourth stripline, and the second bent segment is symmetrically arranged with the first bent segment, resulting in a more compact structure and reduced area occupied, thereby reducing the volume of the dielectric substrate.

[0009] Furthermore, both the first and second bending sections are configured as U-shaped structures, with their openings facing each other, facilitating the welding connection of the corresponding two strips and resulting in a more compact structure.

[0010] Furthermore, the microstrip line module also includes a first defect ground structure and a second defect ground structure disposed on the other side of the dielectric substrate. One end of the first defect ground structure is electrically connected to the other end of the first stripline, and the other end of the first defect ground structure is electrically connected to one end of the third stripline. One end of the second defect ground structure is electrically connected to the other end of the second stripline, and the other end of the second defect ground structure is electrically connected to one end of the fourth stripline. Both the first and second defect ground structures are designed to avoid crossovers in the welding of multiple striplines on the dielectric substrate, facilitating cable routing and welding, and making assembly easier. From the design of the ground plane routing, the first and second defect ground structures also need to be isolated from the ground plane to prevent short circuits.

[0011] Furthermore, the microstrip line module is provided in two sets, and the two sets of microstrip line modules are arranged parallel to each other along the width direction of the dielectric substrate to facilitate the routing of the traces and to match the positive and negative polarizations of the antenna.

[0012] Furthermore, on the other side of the dielectric substrate, pads are provided at the input port, the through port, the isolation port, and the coupling port. These pads are used to connect with the outer conductor of the external coaxial cable, so that the grounding layer and the microstrip line module are electrically connected to form a complete circuit, which improves the stability of welding and fixing, and makes assembly more convenient and faster.

[0013] Furthermore, a plurality of metallized vias are provided on the other side of the dielectric substrate, and each of the pads has a metallized via on its side. The metallized vias can both effectively fix the solder joint and enable the coaxial cable's outer conductor to be grounded.

[0014] Furthermore, the grounding layer is set as a copper foil structure with a thickness of 0.03mm-0.04mm, which provides a large margin in terms of material and power resistance, and has stronger compatibility.

[0015] Furthermore, the dielectric substrate is configured as a polytetrafluoroethylene sheet structure, resulting in lower losses.

[0016] In summary, the beneficial effects of this utility model are as follows:

[0017] In this invention, the first, second, third, and fourth strips are all equipped with serrations. By adjusting the serration gap of each strip, the coupling degree within the 698-960MHz frequency band can be varied between 6-13dB. Adjusting the number of serrations on each strip allows for adjustment of the amplitude slope. Adjusting the width and length of each strip allows for adjustment of the bridge impedance matching and phase characteristics, resulting in a VSWR ≤ 1.11 and ISO ≤ -27dB within the 698-960MHz frequency band. This design offers simple and convenient debugging, higher efficiency, and lower cost. This application can meet the requirements of different horizontal wavewidths in the 703-803MHz / 885-960MHz frequency bands, exhibiting strong compatibility and higher performance. Furthermore, the input port and through port are located at the same end of the dielectric substrate, facilitating cable routing and reducing the occupied area. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of an embodiment of the double-layer microstrip bridge of this utility model.

[0019] Figure 2 This is a rear view of an embodiment of the double-layer microstrip structure bridge of this utility model.

[0020] Figure 3 This is a front view of an embodiment of the microstrip line module of the double-layer microstrip structure bridge of this utility model.

[0021] Figure 4 This is a schematic diagram of the back-side mounting structure of an embodiment of the dielectric substrate of the double-layer microstrip bridge of this utility model.

[0022] Figure 5 This is a graph showing the measured amplitude slope of a bridge according to an embodiment of the double-layer microstrip structure bridge of this utility model.

[0023] Figure 6 This is a graph showing the measured isolation of the double-layer microstrip structure bridge according to an embodiment of this utility model.

[0024] Figure 7 This is a graph showing the measured standing wave of a bridge according to an embodiment of the double-layer microstrip structure bridge of this utility model.

[0025] Explanation of the reference numerals in the figure:

[0026] 1. Double-layer microstrip bridge; 2. Dielectric substrate; 21. Metallized via; 3. Microstrip module; 31. First stripline; 32. Second stripline; 321. First straight segment; 322. First bent segment; 33. Third stripline; 331. Second straight segment; 332. Second bent segment; 34. Fourth stripline; 35. Input port; 36. Through port; 37. Isolation port; 38. Coupling port; 39. Sawtooth; 310. First defective ground structure; 320. Second defective ground structure; 330. Pad; 4. Ground layer; 5. Coaxial cable. Detailed Implementation

[0027] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model are within the protection scope of the present utility model.

[0028] Those skilled in the art should understand that, in the disclosure of this utility model, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," 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 utility model 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. Therefore, the above terms should not be construed as limitations on this utility model.

[0029] In the description of this utility model, the use of terms such as "several" means one or more, with "multiple" meaning two or more. Terms like "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of terms like "first," "second," and "third" is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, the quantity of indicated technical features, or the sequential relationship between indicated technical features.

[0030] The following is in conjunction with the appendix Figure 1-7 The embodiments of this utility model will be described in further detail below.

[0031] A double-layer microstrip bridge structure 1, such as Figure 1 , Figure 2 , Figure 3As shown, it includes a dielectric substrate 2, a microstrip line module 3 disposed on one side of the dielectric substrate 2, and a ground layer 4 disposed on the other side of the dielectric substrate 2. At least one set of microstrip line modules 3 is provided, each including a first stripline 31, a second stripline 32, a third stripline 33, and a fourth stripline 34 arranged in parallel, an input port 35 and a through port 36 disposed at one end of the dielectric substrate 2, and an isolation port 37 and a coupling port 38 disposed at the other end of the dielectric substrate 2. One end of the first stripline 31 is connected to the input port 35, and the other end of the first stripline 31 is electrically connected to one end of the third stripline 33, which is connected to the through port 36. One end of the second stripline 32 is connected to the isolation port 37, and the other end of the second stripline 32 is electrically connected to one end of the fourth stripline 34, which is connected to the coupling port 38. Multiple serrations 39 are sequentially arranged along the length of each adjacent stripline on opposite sides.

[0032] The first strip 31, second strip 32, third strip 33, and fourth strip 34 are all equipped with sawtooth 39. By adjusting the gap between the sawtooth 39 on each strip, the coupling degree within the 698-960MHz frequency band can be varied between 6-13dB. Adjusting the number of sawtooth 39 on each strip allows for adjustment of the amplitude slope. Adjusting the width and length of each strip allows for adjustment of the bridge impedance matching and phase characteristics, resulting in a VSWR ≤ 1.11 and ISO ≤ -27dB within the 698-960MHz frequency band. This design simplifies debugging, increases efficiency, and reduces cost. This application meets the requirements for different horizontal wavewidths in the 703-803MHz / 885-960MHz frequency bands, offering strong compatibility and higher performance. Furthermore, the input port 35 and the through port 36 are located at the same end of the dielectric substrate 2, facilitating cable routing and reducing the footprint.

[0033] In some embodiments, please refer to Figure 1 , Figure 3 The first strip 31 and the fourth strip 34 have the same structure and are both designed as straight-line sawtooth 39 structures. The second strip 32 and the third strip 33 have the same structure. The first strip 31, the fourth strip 34, the second strip 32, and the third strip 33 are 180-degree rotationally symmetrical about the center of the area they enclose. The structure is compact, easy to process and assemble, and has a low cost.

[0034] Preferably, the second strip 32 includes a first straight segment 321 and a first bent segment 322. The first straight segment 321 and the first strip 31 are located on the same horizontal line, and the first bent segment is disposed on one side of the first strip 31. One end of the first bent segment 322 is connected to the first straight segment 321, and the other end of the first bent segment 322 is bent so that both ends of the first bent segment 322 are parallel to the first strip 31. The third strip 33 includes a second straight segment 331 and a second bent segment 332. The second straight segment 331 is disposed on the side of the first bent segment 322 away from the first strip 31, and the second straight segment 331 and the fourth strip 34 are located on the same horizontal line. The second bent segment 332 is disposed between the first straight segment 321 and the fourth strip 34. The second bent segment 332 and the first bent segment 322 are symmetrically arranged, resulting in a more compact structure and reduced area occupied, thereby reducing the volume of the dielectric substrate 2.

[0035] Specifically, both the first bending segment 322 and the second bending segment 332 are designed as U-shaped structures, with the openings of the first bending segment 322 and the second bending segment 332 facing each other, which facilitates the welding connection of the corresponding two strips and makes the structure more compact.

[0036] In some embodiments, please refer to Figure 2 , Figure 4 The microstrip module 3 also includes a first defect ground structure 310 and a second defect ground structure 320 disposed on the other side of the dielectric substrate 2. One end of the first defect ground structure 310 is electrically connected to the other end of the first strip 31, and the other end of the first defect ground structure 310 is electrically connected to one end of the third strip 33. One end of the second defect ground structure 320 is electrically connected to the other end of the second strip 32, and the other end of the second defect ground structure 320 is electrically connected to one end of the fourth strip 34. Both the first defect ground structure 310 and the second defect ground structure 320 are designed to avoid the crossover of multiple strips on the dielectric substrate 2 during soldering, facilitating cable routing and soldering, and making assembly easier. Due to the design of the grounding layer 4, the first defect ground structure 310 and the second defect ground structure 320 also need to be isolated from the grounding layer 4 to prevent short circuits.

[0037] In some embodiments, please refer to Figure 1 The microstrip line module 3 is provided in two sets, and the two sets of microstrip line modules 3 are arranged parallel to each other along the width direction of the dielectric substrate 2 to facilitate the routing of the lines and to match the positive and negative polarizations of the antenna.

[0038] In some embodiments, please refer to Figure 1 , Figure 2On the other side of the dielectric substrate 2, there are pads 330 at the input port 35, through port 36, isolation port 37 and coupling port 38. The pads 330 are used to connect with the outer conductor of the external coaxial cable 5, so that the grounding layer 4 and the microstrip module 3 are electrically connected to form a complete circuit, which improves the stability of welding and fixing, and makes assembly more convenient and faster.

[0039] Preferably, a plurality of metallized vias 21 are provided on the other side of the dielectric substrate 2, and a metallized via 21 is provided on the side of each pad 330. The metallized vias 21 can not only effectively fix the solder joint, but also enable the grounding of the outer conductor of the coaxial cable 5 through the metallized vias 21.

[0040] In some embodiments, the grounding layer 4 is configured as a copper foil structure with a thickness of 0.03mm-0.04mm, preferably 0.035mm or thicker, which provides a large margin in terms of material and power resistance, and enhances compatibility.

[0041] In some embodiments, the dielectric substrate 2 is configured as a polytetrafluoroethylene (PTFE) sheet structure, resulting in lower losses. Preferably, the dielectric substrate 2 is a polytetrafluoroethylene (PTFE) sheet with a dielectric constant DK = 2.2 F / m and a thickness of 0.762 mm.

[0042] Based on the actual measurement results, please refer to... Figure 5 In the curve of the measured amplitude slope of the bridge circuit, the vertical axis (from -5 to -20 dB on the left) represents the transmission loss (dB). The more negative the value, the greater the loss (the smaller the signal). The horizontal axis (0.698, 0.798, 0.898, 0.96 GHz at the bottom) represents the frequency (GHz). The test frequency band is 698 MHz to 960 MHz. As can be seen from the curve of the measured amplitude slope of the bridge circuit, within the 698 MHz to 960 MHz frequency band, the transmission loss exhibits a gentle negative slope as the frequency increases, with a peak-to-peak amplitude change of approximately 1.17 dB.

[0043] Please refer to Figure 6 Bridge isolation refers to the degree of signal leakage between two ports in a bridge that should be isolated. Isolation is one of the key indicators for evaluating bridge performance. A higher (more negative) isolation value is better, indicating less signal leakage. The vertical axis (left side -27 to -32dB) represents isolation (dB), and the horizontal axis (bottom 0.698, 0.798, 0.898, 0.96GHz) represents frequency (GHz). The test frequency band was 698MHz to 960MHz. The actual isolation curve shown in the figure indicates that the bridge's isolation in the 0.7-0.96GHz band is between -27dB and -32dB, with ISO ≤ -27dB, demonstrating excellent performance. Combined with the measured amplitude slope curve of the bridge, this bridge exhibits good performance in terms of transmission loss and excellent isolation performance.

[0044] Please refer to Figure 7 VSWR (Voltage Standing Wave Ratio) is a key parameter for measuring port impedance matching; a perfectly matched VSWR is 1.0. As can be seen from the measured VSWR curves of the bridge circuit, the VSWR ≤ 1.11 in the frequency range of 698-960MHz.

[0045] Therefore, this dual-layer microstrip bridge 1 can achieve a coupling strength of 6-13dB in the 698-960MHz frequency band by adjusting the coupling gap of the sawtooth 39 strip lines, allowing for flexible adjustment of the antenna's horizontal wavewidth to meet different performance requirements. By adjusting the width of each strip line, the VSWR is ≤1.11 and ISO ≤-27dB within the 698-960MHz frequency range. The input port 35 and the through port 36 are located at the same end of the dielectric substrate 2, eliminating the need for cross-soldering of cables and simplifying operation.

[0046] The microstrip line module 3 has four ports: an input port 35, a through port 36, a coupling port 38, and an isolation port 37. The solder joints for each port are located on the other side of the dielectric substrate 2, and are connected to the microstrip line on the dielectric substrate 2 via coaxial cables. The serrated 39-shaped microstrip line is part of the main transmission path. Four serrated 39-shaped microstrip lines are placed side-by-side, allowing electromagnetic energy to couple from one end of the microstrip line to the other. The coupling strength between adjacent microstrip lines can be adjusted by changing the gap between each microstrip line; the coupling strength can range from 6dB to 13dB. The slope of the amplitude can be adjusted by changing the number of serrations 39 on each microstrip line. The impedance matching and phase characteristics can be optimized by adjusting the width of each microstrip line. The ground layer 4 on the other side of the dielectric substrate 2 has a first defective ground structure 310 and a second defective ground structure 320. These two defective ground structures prevent intersections between the two microstrip lines and must also be isolated from the ground plane to prevent short circuits. This double-layer microstrip bridge 1 adopts a back-feed method. The dielectric substrate 2 has a pad 330 on the side away from the strip line. The ground layer 4 is connected to the four strip lines through a coaxial line to form a complete circuit. The power supply method can be adjusted according to actual use.

[0047] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Identical components are represented by the same reference numerals. Therefore, all equivalent changes made to the structure, shape, and principle of this application should be covered within the scope of protection of this application.

Claims

1. A double-layer microstrip bridge structure, characterized in that, The system includes a dielectric substrate (2), a microstrip line module (3) disposed on one side of the dielectric substrate (2), and a ground layer (4) disposed on the other side of the dielectric substrate (2); the microstrip line module (3) is provided in at least one set, and the microstrip line module (3) includes a first stripline (31), a second stripline (32), a third stripline (33), and a fourth stripline (34) disposed in parallel, an input port (35) and a through port (36) disposed at one end of the dielectric substrate (2), and an isolation port (37) and a coupling port (38) disposed at the other end of the dielectric substrate (2); the first stripline... One end of the first wire (31) is connected to the input port (35), and the other end of the first wire (31) is electrically connected to one end of the third wire (33), and the other end of the third wire (33) is connected to the through port (36); one end of the second wire (32) is connected to the isolation port (37), and the other end of the second wire (32) is electrically connected to one end of the fourth wire (34), and the other end of the fourth wire (34) is connected to the coupling port (38); multiple serrations (39) are sequentially arranged on the opposite side of two adjacent wires along the length direction of the wire.

2. The double-layer microstrip bridge according to claim 1, characterized in that, The first strip (31) and the fourth strip (34) have the same structure and are both set as straight sawtooth (39) structures. The second strip (32) and the third strip (33) have the same structure. The first strip (31), the fourth strip (34), the second strip (32), and the third strip (33) are 180 degrees rotationally symmetrical about the center of the area they enclose.

3. The double-layer microstrip bridge according to claim 2, characterized in that, The second strip (32) includes a first straight segment (321) and a first bent segment (322); the first straight segment (321) and the first strip (31) are located on the same horizontal line, and the first bent segment is disposed on one side of the first strip (31); one end of the first bent segment (322) is connected to the first straight segment (321), and the other end of the first bent segment (322) is bent so that both ends of the first bent segment (322) are parallel to the first strip (31); the first The three-band line (33) includes a second straight segment (331) and a second bent segment (332). The second straight segment (331) is located on the side of the first bent segment (322) away from the first band line (31). The second straight segment (331) and the fourth band line (34) are located on the same horizontal line. The second bent segment (332) is located between the first straight segment (321) and the fourth band line (34). The second bent segment (332) and the first bent segment (322) are symmetrically arranged.

4. The double-layer microstrip bridge according to claim 3, characterized in that, Both the first bending segment (322) and the second bending segment (332) are configured as U-shaped structures, and the openings of the first bending segment (322) and the second bending segment (332) are arranged facing each other.

5. The double-layer microstrip bridge according to claim 1, characterized in that, The microstrip module (3) further includes a first defect ground structure (310) and a second defect ground structure (320) disposed on the other side of the dielectric substrate (2); one end of the first defect ground structure (310) is electrically connected to the other end of the first strip (31), and the other end of the first defect ground structure (310) is electrically connected to one end of the third strip (33); one end of the second defect ground structure (320) is electrically connected to the other end of the second strip (32), and the other end of the second defect ground structure (320) is electrically connected to one end of the fourth strip (34).

6. The double-layer microstrip bridge according to claim 1, characterized in that, The microstrip line module (3) is provided in two sets, and the two sets of microstrip line modules (3) are arranged parallel to each other along the width direction of the dielectric substrate (2).

7. The double-layer microstrip bridge according to claim 1, characterized in that, On the other side of the dielectric substrate (2), pads (330) are provided at the input port (35), the through port (36), the isolation port (37) and the coupling port (38). The pads (330) are used to connect with the outer conductor of the external coaxial cable (5) so that the ground layer (4) is electrically connected to the microstrip module (3) to form a complete path.

8. The double-layer microstrip bridge according to claim 7, characterized in that, A plurality of metallized vias (21) are provided on the other side of the dielectric substrate (2), and each pad (330) is provided with a metallized via (21) on its side.

9. The double-layer microstrip bridge according to claim 1, characterized in that, The grounding layer (4) is configured as a copper foil structure with a thickness of 0.03mm-0.04mm.

10. The double-layer microstrip bridge according to claim 1, characterized in that, The dielectric substrate (2) is configured as a polytetrafluoroethylene sheet structure.

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