A high directivity multilayer dielectric substrate coupler

Abstract

The application discloses a high-directivity multilayer dielectric substrate coupler, and belongs to the electronic technical field, which comprises a dielectric substrate body, an external electrode and an internal conductor; the dielectric substrate body is composed of multilayer dielectric substrate superposition, the external electrode comprises a port electrode and a grounding electrode; the internal conductor comprises a first transmission line, a second transmission line, a cancellation rod, a grounding strip and a conductor column; two transmission lines adopt a wide-side coupling form; the application creatively proposes a cancellation rod structure on the basis of a traditional coupler; the cancellation rod is parallelly coupled with the second transmission line near a coupling port to generate a signal, and then the signal is parallelly coupled with the second transmission line near an isolation port through the cancellation rod to generate a signal, finally, the signal is inversely cancelled with a leaked signal, so that the isolation degree is effectively improved, and the directivity is further improved; the grounding strip and the conductor column adjust the coupling degree by directly affecting the coupling window size of the first transmission line and the second transmission line; through three-dimensional wiring of the multilayer dielectric substrate, the device miniaturization can be realized.

Description

Technical Field

[0001] This invention belongs to the field of electronic technology, and specifically relates to a highly directional multilayer dielectric substrate coupler. Background Technology

[0002] A coupler is an important passive device in radio frequency (RF) circuits. It is a power distribution device that extracts a portion of the signal from the main signal path. A good coupler not only requires low VSWR and low loss, but also needs to meet design specifications for coupling and high directivity.

[0003] like Figure 1 As shown, the prototype circuit of the coupler consists of two closely spaced transmission lines, which couple when they are close together. These two transmission lines connect the input port and the through port to the isolation port and the coupling port, respectively. Most of the signal at the input end of the coupler flows into the through port, a portion couples to the coupling port, and a portion leaks to the isolation port. Although theoretically there is no signal at the isolation port, signal leakage is inevitable due to non-ideal factors such as reflections through the coupling port and through port, transmission line bends, end-path connections, and line radiation. The greater the leakage, the worse the isolation. The directivity of the coupler is obtained by subtracting the coupling degree from the isolation degree. Traditional couplers generally use coupled transmission lines. When designing a weakly coupled device, it is difficult to achieve high directivity because the isolation degree cannot be improved simply by modifying the prototype circuit. Furthermore, miniaturization of microwave devices has become a development trend. Multilayer dielectric substrate layout design is an effective way to achieve miniaturization. This technology allows for three-dimensional integration of transmission lines or reactive components, achieving miniaturization. Summary of the Invention

[0004] In view of this, the present invention provides a highly directional multilayer dielectric substrate coupler, which uses a cancellation rod to extract a portion of the signal from the coupling port, so that the extracted signal cancels out the signal leaked from the isolation port, thereby effectively improving the isolation and thus improving the directivity of the weakly coupled coupler. At the same time, miniaturization is achieved through three-dimensional wiring of the multilayer dielectric substrate.

[0005] This invention is achieved through the following technical solution:

[0006] A highly directional multilayer dielectric substrate coupler includes: a dielectric substrate body, external electrodes, and internal conductors;

[0007] The dielectric substrate body is composed of multiple layers of dielectric substrates stacked together;

[0008] The external electrodes are printed on the outer surface of the dielectric substrate body and include a ground electrode and four port electrodes; there is no electrical connection between the four port electrodes and the ground electrode; the coupler has four ports, namely an input port, a through port, a coupled port and an isolation port;

[0009] The internal conductor includes: a cancellation rod, a first transmission line, a second transmission line and more than two ground strips; the cancellation rod is mounted on the dielectric substrate; the first transmission line and the second transmission line are respectively mounted on two dielectric substrates of different layers; the more than two ground strips are divided into several groups, and the ground strips of different groups are respectively mounted on the dielectric substrates of different layers;

[0010] The two ends of the first transmission line are respectively connected to the input port and the through port of the coupler, the two ends of the second transmission line are respectively connected to the coupled port and the isolation port of the coupler, and a wide-side coupling form is adopted between the first transmission line and the second transmission line;

[0011] The cancellation rod is made of a conductor material and acts between the coupled port and the isolation port to cancel the signal leaked from the isolation port and improve the directivity;

[0012] Both ends of each ground strip are connected to the ground electrode and are located between the first transmission line and the second transmission line to adjust the coupling degree deviation of the coupler.

[0013] Further, the dielectric substrate body is composed of multiple dielectric substrates with different layer thicknesses stacked together.

[0014] Further, the distance between the two transmission lines is adjusted by adjusting the number of layers of the dielectric substrate.

[0015] Further, the distance between the cancellation rod and the second transmission line is less than the distance between the cancellation rod and the first transmission line.

[0016] Further, let the two ends of the cancellation rod be the A end and the B end respectively, where the distance between the A end and the isolation port is less than the distance from the A end to the coupled port, and the distance between the B end and the coupled port is less than the distance from the B port to the isolation port;

[0017] The line segment at the A end of the cancellation rod is parallel to the line segment at the isolation port of the second transmission line and generates coupling; the line segment at the B end of the cancellation rod is parallel to the line segment at the coupled port of the second transmission line and generates coupling.

[0018] Further, by changing the position and line width of the ground strip, the size of the coupling window between the two transmission lines and the coupling degree between the two transmission lines can be adjusted;

[0019] Where the position of the ground strip is the distance between every two adjacent ground strips in each group of ground strips or the distance between the ground strips in different groups.

[0020] Furthermore, the internal circuit also includes one or more conductor posts; the conductor posts are arranged along the thickness direction of the multilayer dielectric substrate, and different groups of grounding bars are connected by conductor posts, which are used to enhance the effect of the grounding bars.

[0021] Beneficial effects:

[0022] (1) A highly directional multilayer dielectric substrate coupler of the present invention includes a dielectric substrate body, an external electrode, and an internal electrode. The external electrode is printed on the outer surface of the dielectric substrate body. The internal electrode includes a first transmission line, a second transmission line, a canceling rod, and two or more grounding bars. The first transmission line and the second transmission line are coupled in a wide-edge manner. The two ends of the first transmission line are respectively connected to an input port and a through port. The two ends of the second transmission line are respectively connected to a coupling port and an isolation port. The canceling rod acts between the coupling port and the isolation port. The grounding bars are located between the two transmission lines. The highly directional multilayer dielectric substrate coupler can cancel the signal leakage of the isolation port through the coupling effect of the canceling rod, thereby improving the isolation and achieving high directivity. The highly directional multilayer dielectric substrate coupler achieves three-dimensional integration through multilayer dielectric substrates, which can realize the miniaturization of the coupler. Different groups of grounding bars are respectively installed on different layers of dielectric substrates and located between the first transmission line and the second transmission line. The coupling deviation of the coupler can be adjusted through the grounding bars, so that the coupling of the coupler meets the requirements.

[0023] (2) A highly directional multilayer dielectric substrate coupler of the present invention is composed of multiple dielectric substrates of different thicknesses stacked together. By using dielectric substrates of different thicknesses, the coupling degree can be easily adjusted and the design thickness can be easily adjusted.

[0024] (3) In a high-directivity multilayer dielectric substrate coupler of the present invention, the line segment at end A of the cancelling rod is parallel to and coupled with the line segment at the isolation port of the second transmission line, and the line segment at end B of the cancelling rod is parallel to and coupled with the line segment at the coupling port of the second transmission line. A portion of the signal is generated by the parallel coupling between the cancelling rod and the coupling port, and the portion of the signal is transmitted to the isolation port through the cancelling rod and coupled with the isolation port again. The generated signal cancels out the signal leaked by the isolation port, effectively improving the isolation and thus improving the directivity.

[0025] (4) The high-directivity multilayer dielectric substrate coupler of the present invention has a grounding bar whose position and line width can be changed. By changing the position and line width of the grounding bar, the size of the coupling window of the two transmission lines can be controlled, thereby adjusting the coupling degree between the two transmission lines and thus adjusting the coupling degree of the coupler.

[0026] (5) The present invention provides a highly directional multilayer dielectric substrate coupler, the internal circuit of which also includes conductor pillars. The conductor pillars can enhance the effect of the grounding bar, so that the coupling degree of the coupler is within the design specifications. Attached Figure Description

[0027] Figure 1 The circuit diagram is shown for the prototype circuit of the coupler in the background art.

[0028] Figure 2 This is a schematic diagram of the packaging of the present invention;

[0029] Figure 3 This is a schematic diagram of the conductor structure of the present invention;

[0030] Figure 4 The test results for the return loss of this invention;

[0031] Figure 5 The results are the test results of the insertion loss of this invention;

[0032] Figure 6 The results of the coupling degree test for this invention;

[0033] Figure 7 The test results are for the directionality of this invention;

[0034] Among them, 1-input port, 2-through port, 3-coupled port, 4-isolation port, 5-ground electrode, 6-cancellation rod, 7-second transmission line, 8-grounding bar, 9-conductor post, 10-first transmission line, 11-top electrode, and 12-bottom electrode. Detailed Implementation

[0035] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0036] This embodiment provides a highly directional multilayer dielectric substrate coupler, including: a dielectric substrate body, external electrodes, and internal conductors;

[0037] The dielectric substrate body is composed of multiple layers of dielectric substrates with the same or different layer thicknesses stacked together. In this embodiment, the dielectric substrate body is composed of 18 layers of dielectric substrates stacked together according to the height of the coupler. The 18 layers of dielectric substrates are C01 layer to C18 layer from bottom to top. In this embodiment, multiple layers of dielectric substrates with different layer thicknesses are used. The dielectric substrates include two thicknesses: 0.044mm and 0.108mm. Since the coupler adopts a wide-edge coupling method, the use of dielectric substrates with two thicknesses stacked together can facilitate the adjustment of both the coupling degree and the design thickness. The process of the multilayer dielectric substrate can be realized by any multilayer, three-dimensional structure. By using the multilayer dielectric substrate process, the miniaturization design of the coupler can be achieved. In this embodiment, the dielectric substrate is made of LTCC material.

[0038] like Figure 2 As shown, a plurality of solderable metal conductor surfaces are printed on the outer surface of the dielectric substrate body, and the solderable metal conductor surfaces form the external electrodes 5. Figure 2 The external electrodes are indicated by slashes; the external electrodes 5 include: such as Figure 2 As shown, there are four port electrodes and a ground electrode 5. Each of the four port electrodes and the ground electrode 5 is composed of a top electrode 11, a bottom electrode 12, and a side electrode. There is a gap between the four port electrodes and the ground electrode 5, and there is no electrical connection between them.

[0039] The highly directional multilayer dielectric substrate coupler includes four ports, with four port electrodes corresponding to the four ports respectively; the four ports are: input port 1, through port 2, coupling port 3, and isolation port 4; in this embodiment, the solderable metal conductor surface is made of silver, and the four port electrodes are respectively located at the four edges of the dielectric substrate body, and the side markings forming the four port electrodes are semi-circular.

[0040] The internal conductor is disposed within the dielectric substrate body, such as Figure 3As shown, the internal conductor includes: a canceling rod 6, several grounding strips 8, several conductor pillars 9, and a pair of coupling lines composed of two transmission lines; the two transmission lines are coupled in a wide-side coupling form, and the two transmission lines are respectively disposed on dielectric substrates of different layers. The distance between the two transmission lines is controlled by adjusting the number of layers of the dielectric substrate (the distance between the two transmission lines is changed by adjusting the number of layers of the dielectric substrate, thereby controlling the magnitude of the coupling); let the two transmission lines be the first transmission line 10 and the second transmission line 7; wherein the two ends of the first transmission line 10 are respectively connected to the input port 1 and the through port 2, and the two ends of the second transmission line 7 are respectively connected to the coupling port 3 and the isolation port 4; in this embodiment, the first transmission line 10 is disposed on the dielectric substrate of the C04 layer, and the second transmission line 7 is disposed on the dielectric substrate of the C14 layer; several grounding strips 8 are respectively disposed on the dielectric substrate between the C04 layer and the C14 layer, and are located between the first transmission line 10 and the second transmission line 7; several grounding strips 8 are strip-shaped, each Both ends of each grounding bar 8 are connected to the grounding electrode 5 on the side of the dielectric substrate body; the grounding bars 8 are divided into several groups, and the grounding bars 8 in different groups are respectively installed on two dielectric substrates on different layers; the grounding bars 8 are used to adjust the coupling degree of the coupler. By adjusting the position and line width of the grounding bars 8, the size of the coupling window of the two transmission lines can be adjusted, the coupling degree deviation between the first transmission line 10 and the second transmission line 7 can be adjusted, and the isolation degree can also be improved to a certain extent; the position of the grounding bars 8 includes the distance between every two adjacent grounding bars 8 in each group and the distance between grounding bars 8 in different groups; the grounding bars 8 in different groups are connected by conductor posts 9; the conductor posts 9 are used to enhance the effect of the grounding bars 8, so that the coupling degree of the coupler is within the design specifications; this embodiment includes three groups of grounding bars 8, and the grounding bars 8 in different groups are respectively located on the C07, C09 and C11 layers; the coupler in this embodiment is a weak coupling device, and the coupling index of the coupler, i.e., the coupling degree, is 30dB;

[0041] The cancelling rod 6 is made of a conductor material. The distance between the cancelling rod 6 and the second transmission line 7 is less than the distance between the cancelling rod 6 and the first transmission line 10. The cancelling rod 6 acts between the coupling port 3 and the isolation port 4. Let the two ends of the cancelling rod 6 be end A and end B, where the distance between end A and the isolation port 4 is less than the distance from port A to the coupling port 3, and the distance between end B and the coupling port 3 is less than the distance from port B to the isolation port 4. The line segment at end A of the cancelling rod 6 is parallel to and coupled with the line segment at the isolation port 4 of the second transmission line 7. The line segment at end B of the cancelling rod 6 is parallel to and coupled with the line segment at the coupling port 3 of the second transmission line 7. The closer the distance between the line segments of the cancelling rod 6 and the second transmission line 7 that are coupled, and the longer the coupling area, the greater the coupling degree. The cancelling rod 6 can be located on the dielectric substrate on which the second transmission line 7 is set or on any dielectric substrate close to the second transmission line 7. To prevent interference from other effects and due to size limitations, in this embodiment, the cancelling rod 6 is set on layer C16 (not on the same layer as the second transmission line 7).

[0042] This design operates at a frequency of 2GHz-4GHz, with a VSWR of <1.2, a coupling requirement of 30dB±1.5dB, an insertion loss of <0.2dB, and a directivity of >25dB. The parameters of the coupler after installing the cancellation rod 6 are as follows: Figures 4 to 7 As shown, Figures 4 to 7 The return loss, insertion loss, coupling degree, and directivity of the coupler in this embodiment are represented in turn. Figure 4 The four line segments contained herein represent the return losses of the four ports, where S(1,1) represents the return loss of input port 1, S(2,2) represents the return loss of through port 2, S(3,3) represents the return loss of coupled port 3, and S(4,4) represents the return loss of isolation port 4; for example Figure 6 As shown, the coupling degree of the coupler is about 30dB, which belongs to the category of weakly coupled couplers; Figure 7 As shown, the directivity of the weakly coupled coupler is higher than 25dB. Test data shows that the coupler has good electrical performance and the high directivity of the coupler can be effectively achieved by introducing the cancelling rod 6.

[0043] In this embodiment, the dielectric substrate uses LTCC material, the device package size requirement is 3.18mm × 2.54mm, and the actual size of the coupler is 3.18mm × 2.54mm × 1.3mm.

[0044] Working principle:

[0045] Let S0 be a portion of the signal leaked from isolation port 4 in the circular circuit; the conductor segment at end B of the cancelling rod 6 is coupled with the conductor segment parallel to the coupling port 3 of the second transmission line 7, generating a coupling signal, which is transmitted to end A of the cancelling rod 6 through the cancelling rod 6; the conductor segment parallel to the isolation port 4 is coupled with end A of the cancelling rod 6, and the coupling signal is coupled to the isolation port 4, which is denoted as S1; the magnitude and phase of S1 are adjusted by adjusting the position, length, line width, and other parameters of the cancelling rod 6, so that S1 and S0 are equal in magnitude but opposite in phase, thus canceling each other out; the magnitude of S1 is adjusted by adjusting the coupling distance and length between the cancelling rod 6 and the second transmission line 7, and the phase of S1 is adjusted by adjusting the length of the cancelling rod 6.

[0046] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A highly directional multilayer dielectric substrate coupler, characterized in that, include: Dielectric substrate body, external electrodes and internal conductors; The dielectric substrate body is composed of multiple layers of dielectric substrates stacked together; External electrodes are printed on the outer surface of the dielectric substrate body, including a ground electrode and four port electrodes; There is no electrical connection between the four port electrodes and the ground electrode; The coupler has four ports: an input port, a pass-through port, a coupling port, and an isolation port. The internal conductor includes: a canceling rod, a first transmission line, a second transmission line, and two or more grounding bars; the canceling rod is mounted on a dielectric substrate; the first transmission line and the second transmission line are respectively mounted on two dielectric substrates of different layers; the two or more grounding bars are divided into several groups, and the grounding bars of different groups are respectively mounted on dielectric substrates of different layers; The first transmission line is connected to the input port and the through port of the coupler at both ends, and the second transmission line is connected to the coupling port and the isolation port of the coupler at both ends. The first transmission line and the second transmission line are coupled in a wide-side coupling manner. The cancelling rod is made of conductive material and acts between the coupling port and the isolation port to cancel out the signal leakage at the isolation port and improve directivity; Each grounding bar is connected to a grounding electrode at both ends and is located between the first and second transmission lines to adjust the coupling deviation of the coupler.

2. The highly directional multilayer dielectric substrate coupler as described in claim 1, characterized in that, The dielectric substrate body is composed of multiple dielectric substrates of different thicknesses stacked together.

3. The highly directional multilayer dielectric substrate coupler as described in claim 1, characterized in that, The distance between the first transmission line and the second transmission line is adjusted by adjusting the number of layers in the dielectric substrate.

4. The highly directional multilayer dielectric substrate coupler as described in claim 1, characterized in that, The distance between the canceling rod and the second transmission line is less than the distance between the canceling rod and the first transmission line.

5. The highly directional multilayer dielectric substrate coupler as described in claim 4, characterized in that, Let the two ends of the canceling rod be end A and end B, respectively, wherein the distance between end A and the isolation port is less than the distance between end A and the coupling port, and the distance between end B and the coupling port is less than the distance between port B and the isolation port. The line segment at end A of the cancelling rod is parallel to and coupled with the line segment at the isolation port of the second transmission line; the line segment at end B of the cancelling rod is parallel to and coupled with the line segment at the coupling port of the second transmission line.

6. The highly directional multilayer dielectric substrate coupler as described in claim 1, characterized in that, By changing the position and width of the grounding bar, the size of the coupling window between the two transmission lines can be adjusted, and the coupling degree between the two transmission lines can be adjusted. The position of the grounding bar is the distance between any two adjacent grounding bars in each group or the distance between grounding bars in different groups.

7. A highly directional multilayer dielectric substrate coupler as described in any one of claims 1-6, characterized in that, The internal conductor also includes one or more conductor posts; the conductor posts are arranged along the thickness direction of the multilayer dielectric substrate, and different groups of grounding bars are connected by conductor posts, which are used to enhance the effect of the grounding bars.

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