Bidirectional coupler

Abstract

The present invention provides a bidirectional coupler and a radio frequency module. The bidirectional coupler includes a silicon oxide layer, an insulating layer, a first metal layer, a second metal layer, and a third metal layer that are sequentially stacked and fixed, a transmission line fixed in the third metal layer, a patch cord fixed in the second metal layer, a coupling line fixed in the first metal layer, a connection hole penetrating from the first metal layer to the second metal layer, and a connection line; the area of the positive projection of the first metal layer on the third metal layer is 30-40% of the side area of the third metal layer; the width of the coupling line is less than 10 μm, the distance between the patch cord and the transmission line is less than 5 μm, and the distance between the patch cord and the coupling line is less than 5 μm. The present invention can improve the coupling degree and isolation degree of the bidirectional coupler, reduce its insertion loss, achieve large bandwidth and miniaturization, and at the same time achieve high-density integration in radio frequency components.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technologies, and particularly to a bidirectional coupler. Background Art

[0002] In a wireless communication system, the efficient transmission and precise monitoring of radio frequency signals are one of the key factors to ensure the system performance. As an important radio frequency component in the communication system, the bidirectional coupler has now been widely used in fields such as signal monitoring, power measurement, and antenna matching.

[0003] The bidirectional coupler is usually implemented by using microstrip line or waveguide technology, but it often faces problems such as high insertion loss, insufficient isolation, and large volume in high-frequency band and broadband applications, making it difficult to meet the requirements of high-performance radio frequency components.

[0004] With the development of SOI (Silicon on Insulator) technology, radio frequency components based on SOI materials have been widely used due to their advantages such as low parasitic capacitance, high isolation, and easy integration. The SOI material consists of a top layer of silicon, a buried oxide layer (BOX), and a supporting substrate. The buried oxide layer provides a natural electrical isolation effect, which helps to improve the isolation and directivity of the device. In addition, the SOI technology also allows multiple radio frequency components to be integrated on the same chip, greatly reducing the volume and complexity of the radio frequency components.

[0005] Although the bidirectional coupler based on SOI technology has advantages such as high isolation, high directivity, small volume, and easy integration. It still has several disadvantages: the first disadvantage is that too high coupling degree will lead to increased insertion loss or insufficient isolation resulting in signal interference; the second disadvantage is that the covered frequency range is too narrow; the third disadvantage is that it is impossible to further reduce its size and achieve high-density integration with other radio frequency components while ensuring performance. Summary of the Invention

[0006] Aiming at the above deficiencies of the prior art, the present invention proposes a bidirectional coupler and a radio frequency module with high coupling degree, high isolation, low insertion loss, large bandwidth, miniaturization, and high-density integration in radio frequency components.

[0007] To solve the above technical problems, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a bidirectional coupler, which includes a silicon oxide layer, an insulating layer formed on one side of the silicon oxide layer, a first metal layer formed on the side of the insulating layer away from the silicon oxide layer, a second metal layer formed on the side of the first metal layer away from the insulating layer and insulated from the first metal layer, a third metal layer formed on the side of the second metal layer away from the first metal layer and insulated from the second metal layer, a transmission line buried and fixed in the third metal layer and insulated from the third metal layer, a jumper wire buried and fixed in the second metal layer and insulated from the second metal layer, a coupling wire buried and fixed in the first metal layer and insulated from the first metal layer, a connection hole penetrating from the side of the first metal layer away from the second metal layer to the side of the second metal layer away from the first metal layer, and a connection wire; the coupling wire is coupled with the transmission line, both ends of the jumper wire are respectively connected to the transmission line and the coupling wire, both ends of the connection hole are respectively connected to the transmission line and the coupling wire, and both ends of the transmission line are respectively used as the signal input end and the signal output end of the bidirectional coupler; the connection hole and the connection wire each include two, one end of each of the two connection wires is respectively connected to the two connection holes, and the other end of each of the two connection wires is respectively used as the isolation end and the coupling end of the bidirectional coupler;

[0009] The area of the positive projection of the first metal layer on the third metal layer is 30-40% of the area of the side of the third metal layer close to the first metal layer; the width of the coupling wire is less than 10 μm.

[0010] Preferably, the width of the coupling wire is 6 μm.

[0011] Preferably, both the first metal layer and the second metal layer are made of copper; the third metal layer is made of aluminum.

[0012] Preferably, the thickness of the first metal layer is 0.29 μm; the thickness of the second metal layer is 0.32 μm; the thickness of the third metal layer is 4 μm.

[0013] Preferably, the transmission line is U-shaped; the jumper wire includes two and is arranged at intervals; the coupling wire includes a first coupling wire and a second coupling wire arranged at intervals;

[0014] The first coupling line includes a first vertical section and a first U-shaped section that is bent and extended from one end of the first vertical section and is U-shaped; one end of the first vertical section away from the first U-shaped section is connected to one of the connection holes, and one end of the first U-shaped section away from the first vertical section is connected to one of the patch cords. The orthographic projection of the first vertical section and the first U-shaped section onto the transmission line is completely located on the transmission line.

[0015] The second coupling line includes a second vertical section, a second U-shaped section that is bent and extended from one end of the second vertical section and is U-shaped, an inclined section that is bent and extended from one end of the second U-shaped section away from the second vertical section towards the second vertical section, and a surrounding section that is bent and extended from one end of the inclined section away from the second U-shaped section and extends around the inner sides of the first U-shaped section and the second U-shaped section and has a rectangular structure with an opening. One end of the second vertical section away from the second U-shaped section is connected to the connection hole, and one end of the surrounding section away from the inclined section is connected to the other patch cord. The orthographic projections of the first vertical section and the inclined section onto the transmission line are both completely located on the transmission line. The orthographic projection of the part of the second U-shaped section facing the transmission line onto the transmission line is completely located on the transmission line. The orthographic projection of the part of the surrounding section facing the transmission line onto the transmission line is completely located on the transmission line.

[0016] Preferably, the distance between the first coupling line and the second coupling line is less than 5 μm.

[0017] In a second aspect, the present invention provides a radio frequency module, which includes the bidirectional coupler as described above.

[0018] Compared with the prior art, in the bidirectional coupler of the present invention, by optimizing the arrangement and connection methods of the silicon oxide layer, the insulating layer, the first metal layer, the second metal layer, the third metal layer, the transmission line, the patch cord, the coupling line, the connection hole, and the connection line, and defining that the orthographic projection area of the first metal layer on the third metal layer is 30 - 40% of the side area of the third metal layer facing the first metal layer, and the width of the coupling line is less than 10 μm, the coupling degree and isolation degree of the bidirectional coupler can be improved, its insertion loss can be reduced, large bandwidth and miniaturization can be achieved, and high-density integration can be realized in the radio frequency component. Furthermore, after being applied to the radio frequency component, the overall performance can be improved. Description of the Drawings

[0019] The present invention will be described in detail below with reference to the drawings. Through the detailed description in combination with the following drawings, the above or other aspects of the present invention will become clearer and easier to understand. In the drawings:

[0020] Figure 1Schematic diagram of the three-dimensional structure of the transmission line, patch cord, coupling line, connection hole and the connection hole after connection in the bi-directional coupler provided by the embodiment of the present invention;

[0021] Figure 2 Top view of the transmission line, patch cord, coupling line, connection hole and the connection hole after connection in the bi-directional coupler provided by the embodiment of the present invention;

[0022] Figure 3 Side view of the transmission line, patch cord, coupling line, connection hole and the connection hole after connection in the bi-directional coupler provided by the embodiment of the present invention;

[0023] Figure 4 Stacking diagram of the bi-directional coupler provided by the embodiment of the present invention;

[0024] Figure 5 Simulation result diagram of the coupling coefficient and isolation coefficient of the bi-directional coupler provided by the embodiment of the present invention.

[0025] Among them, 100, bi-directional coupler; 1, silicon oxide layer; 2, insulating layer; 3, first metal layer; 4, second metal layer; 5, third metal layer; 6, transmission line; 7, patch cord; 8, coupling line; 81, first coupling line; 811, first vertical section; 812, first U-shaped section; 82, second coupling line; 821, second vertical section; 822, second U-shaped section; 823, inclined section; 824, surrounding section; 9, connection hole; 91, first connection hole; 92, second connection hole; 10, connecting line. Detailed implementation manners

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above drawings are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the specification and claims of this application or the above drawings are used to distinguish different objects and not to describe a specific order.

[0027] Reference to "embodiment" herein means that a particular feature, structure or characteristic described in connection with the embodiment can be included in at least one embodiment of this application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0028] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0029] Embodiment 1

[0030] An embodiment of the present invention provides a bidirectional coupler 100, which includes a silicon oxide layer 1, an insulating layer 2 formed on one side of the silicon oxide layer 1, a first metal layer 3 formed on the side of the insulating layer 2 away from the silicon oxide layer 1, a second metal layer 4 formed on the side of the first metal layer 3 away from the insulating layer 2 and insulated from the first metal layer 3, a third metal layer 5 formed on the side of the second metal layer 4 away from the first metal layer 3 and insulated from the second metal layer 4, a transmission line 6 buried and fixed in the third metal layer 5 and insulated from the third metal layer 5, a jumper wire 7 buried and fixed in the second metal layer 4 and insulated from the second metal layer 4, a coupling wire 8 buried and fixed in the first metal layer 3 and insulated from the first metal layer 3, a connection hole 9 penetrating from the side of the first metal layer 3 away from the second metal layer 4 to the side of the second metal layer 4 away from the first metal layer 3, and a connection wire 10.

[0031] Among them, the coupling wire 8 is coupled to the transmission line 6, both ends of the jumper wire 7 are respectively connected to the transmission line 6 and the coupling wire 8, both ends of the connection hole 9 are respectively connected to the transmission line 6 and the coupling wire 8, and both ends of the transmission line 6 are respectively used as the signal input end and the signal output end of the bidirectional coupler 100; the connection hole 9 and the connection wire 10 each include two, one end of each of the two connection wires 10 is respectively connected to the two connection holes 9, and the other end of each of the two connection wires 10 is respectively used as the isolation end and the coupling end of the bidirectional coupler 100.

[0032] The area of the positive projection of the first metal layer 3 on the third metal layer 5 is 30-40% of the area of the side of the third metal layer 5 close to the first metal layer 3.

[0033] Both the first metal layer 3 and the second metal layer 4 are made of copper (Cu); the third metal layer 5 is made of aluminum (Al). Of course, according to actual needs, the materials of the first metal layer 3, the second metal layer 4, and the third metal layer 5 can also be adaptively modified.

[0034] The thickness of the first metal layer 3 is 0.29 μm; the thickness of the second metal layer 4 is 0.32 μm; the thickness of the third metal layer 5 is 4 μm. Of course, according to actual needs, the thicknesses of the first metal layer 3 and the third metal layer 5 can also be adaptively improved.

[0035] In this embodiment, asFigure 1 and Figure 2 As shown in Figure 2 , the transmission line 6 is U-shaped; the adapter line 7 includes two and is arranged at intervals; the coupling line 8 includes a first coupling line 81 and a second coupling line 82 arranged at intervals.

[0036] The first coupling line 81 includes a first vertical section 811 and a first U-shaped section 812 that is bent and extended from one end of the first vertical section 811 and is U-shaped; one end of the first vertical section 811 far from the first U-shaped section 812 is connected to one of the connection holes 9, and one end of the first U-shaped section 812 far from the first vertical section 811 is connected to one of the adapter lines 7. The orthographic projections of the first vertical section 811 and the first U-shaped section 812 onto the transmission line 6 are completely located on the transmission line 6.

[0037] The second coupling line 82 includes a second vertical section 821, a second U-shaped section 822 that is bent and extended from one end of the second vertical section 821 and is U-shaped, an inclined section 823 that is bent and extended from one end of the second U-shaped section 822 far from the second vertical section 821 in the direction of approaching the second vertical section 821 inward, and a surrounding section 824 that is bent and extended from one end of the inclined section 823 far from the second U-shaped section 822 and extends around the inner sides of the first U-shaped section 812 and the second U-shaped section 822 and has a rectangular structure with an opening; one end of the second vertical section 821 far from the second U-shaped section 822 is connected to the connection hole 9, and one end of the surrounding section 824 far from the inclined section 823 is connected to the other adapter line 7. The orthographic projections of the first vertical section 811 and the inclined section 823 onto the transmission line 6 are completely located on the transmission line 6. The orthographic projection of the part of the second U-shaped section 822 facing the transmission line 6 onto the transmission line 6 is completely located on the transmission line 6. The orthographic projection of the part of the surrounding section 824 facing the transmission line 6 onto the transmission line 6 is completely located on the transmission line 6.

[0038] The width of the coupling line 8 is less than 10 μm, and the distance between the first coupling line 81 and the second coupling line 82 is less than 5 μm. Preferably, the width of the coupling line 8 is 6 μm, and the distance between the first coupling line 81 and the second coupling line 82 is less than 3 μm.

[0039] In addition, the area of the orthographic projections of the first coupling line 81 and the second coupling line 82 onto the transmission line 6 accounts for at least more than 30% of the area of this side of the transmission line 6, such as 60 - 70%, 50%, 80%, etc.

[0040] In this embodiment, as Figure 1 and Figure 3As shown, the connection holes 9 and the connection lines 10 each include two. One end of each of the two connection lines 10 is respectively connected to the connection hole 9, and the other ends of the two connection lines 10 serve as the isolation end and the coupling end of the bidirectional coupler 100, that is, the output ports of the isolation end and the coupling end; the first vertical section 811 and the second vertical section 821 are respectively connected to the two connection holes 9.

[0041] The part of the connection hole 9 located in the first metal layer 3 is the first connection hole 91, and the part located in the second metal layer 4 is the second connection hole 92.

[0042] For the convenience of illustration, the transmission line 6, the adapter line 7, and the coupling line 8 in Figure 4 are represented by squares, and the connection method is not shown.

[0043] In the bidirectional coupler 100 of this embodiment, the spatial contact surface between the transmission line 6 and the coupling line 8 forms its coupling coefficient; in order to increase the coupling coefficient of the bidirectional coupler 100, the coupling line 8 makes a layer jump through the adapter line 7. The adapter line 7 is located in the second metal layer 4 and is connected to the coupling line 8 through the first connection hole 91; when the bidirectional coupler 100 is applied to the radio frequency module, various switches of the bidirectional coupler 100 will be connected in the radio frequency module to perform the gating of the coupling end and the isolation end, and the isolation end needs to be connected to the load impedance of the bidirectional coupler 100. Although the two connection lines 10 will be connected to various gating switches, it will not affect the performance of the bidirectional coupler 100. The connection line 10 and the coupling line 8 change layers through the first connection hole 91.

[0044] In the bidirectional coupler 100 of this embodiment, the third metal layer 5 and the first metal layer 3 are parallel-coupled, and the coupling coefficient is determined by the orthographic projection area of the first metal layer 3 on the third metal layer 5; when the bidirectional coupler 100 of this embodiment operates in the frequency range of 1.3 - 2.7 GHz, higher coupling coefficients and isolation coefficients can be achieved.

[0045] The bidirectional coupler 100 in this embodiment is bidirectional. Combining Figure 2 and Figure 5 as shown, when reverse-coupled, P1 represents the signal input end of the bidirectional coupler 100, P2 represents the signal output end of the bidirectional coupler 100, P3 represents the coupling end of the bidirectional coupler 100, P4 represents the isolation end of the bidirectional coupler 100, then S(3,1) represents the coupling coefficient, and S(3,2) represents the isolation coefficient; when forward-coupled, P1 represents the signal output end of the bidirectional coupler 100, P2 represents the signal input end of the bidirectional coupler 100, P3 represents the isolation end of the bidirectional coupler 100, P4 represents the coupling end of the bidirectional coupler 100, then S(4,1) represents the isolation coefficient, and S(4,2) represents the coupling coefficient.

[0046] CombiningFigure 5 As shown in Figure 5 , the bidirectional coupler 100 operates in the frequency band of 1.3 - 2.7 GHz. When coupled in the reverse direction, the curves of the reverse coupling coefficients are approximately coincident, with a deviation of plus or minus 0.2 dB, and the coupling coefficient is between 22 - 28.7 dB. When coupled in the forward direction, the forward isolation coefficient is 1.6 - 2.3 dB better than the reverse isolation coefficient. The forward isolation coefficient is between 48.6 - 63.2 dB, and the reverse isolation coefficient is between 47.0 - 60.8 dB. According to calculations, in this frequency band range, the forward directivity can reach 26.4 - 34.4 dB, and the reverse directivity can reach 24.8 - 32.2 dB. Thus, it can be seen that the bidirectional coupler 100 of this embodiment can achieve excellent coupling coefficients and directivities.

[0047] Compared with the prior art, the bidirectional coupler 100 in this embodiment optimizes the arrangement and connection methods of the silicon oxide layer 1, the insulating layer 2, the first metal layer 3, the second metal layer 4, the third metal layer 5, the transmission line 6, the patch cord 7, the coupling line 8, the via hole 9, and the connection line 10, and defines that the orthographic projection area of the first metal layer 3 on the third metal layer 5 is 30 - 40% of the side area of the third metal layer 5 facing the first metal layer 3, and the width of the coupling line 8 is less than 10 μm. Thereby, the coupling degree and isolation degree of the bidirectional coupler 100 can be improved, its insertion loss can be reduced, large bandwidth and miniaturization can be achieved, and high-density integration can be realized in the RF components. Furthermore, after being applied to the RF components, the overall performance can be improved.

[0048] Embodiment 2

[0049] This embodiment provides a radio frequency module, which includes the bidirectional coupler 100 in the above Embodiment 1. Since the radio frequency module in this embodiment includes the bidirectional coupler 100 in the above Embodiment 1, it can also achieve the technical effects achieved by the bidirectional coupler 100 in the above Embodiment 1, which will not be elaborated here.

[0050] It should be noted that each of the embodiments described above with reference to the accompanying drawings is only used to illustrate the present invention and not to limit the scope of the present invention. Those of ordinary skill in the art should understand that any modifications or equivalent replacements made to the present invention without departing from the spirit and scope of the present invention shall be covered within the scope of the present invention. In addition, unless otherwise specified in the context, words in the singular form include the plural form, and vice versa. Additionally, unless otherwise specified, all or part of any embodiment can be used in combination with all or part of any other embodiment.

Claims

1. A bidirectional coupler, characterized in that: The bidirectional coupler includes a silicon oxide layer, an insulating layer formed on one side of the silicon oxide layer, a first metal layer formed on a side of the insulating layer away from the silicon oxide layer, a second metal layer formed on a side of the first metal layer away from the insulating layer and insulated from the first metal layer, a third metal layer formed on a side of the second metal layer away from the first metal layer and insulated from the second metal layer, a transmission line buried and fixed in the third metal layer and insulated from the third metal layer, a switching line buried and fixed in the second metal layer and insulated from the second metal layer, and a second metal layer buried and fixed in the first metal layer and insulated from the first metal layer. A coupling line is provided, a connection hole and a connection line which penetrate from the side of the first metal layer away from the second metal layer to the side of the second metal layer away from the first metal layer; the coupling line is coupled with the transmission line, the two ends of the adapter line are respectively connected to the transmission line and the coupling line, the two ends of the connection hole are respectively connected to the transmission line and the coupling line, and the two ends of the transmission line serve as the signal input end and the signal output end of the bidirectional coupler respectively; the connection hole and the connection line each include two, one end of each of the two connection lines is respectively connected to the two connection holes, and the other end of each of the two connection lines serves as the isolation end and the coupling end of the bidirectional coupler respectively; The area of ​​the orthographic projection of the first metal layer on the third metal layer is 30-40% of the area of ​​the third metal layer on a side close to the first metal layer; and the width of the coupling line is less than 10 μm.

2. The bidirectional coupler according to claim 1, characterized in that The width of the coupling line is 6 μm.

3. The bidirectional coupler according to claim 1, characterized in that The first metal layer and the second metal layer are both made of copper; the third metal layer is made of aluminum.

4. The bidirectional coupler according to claim 3, characterized in that The thickness of the first metal layer is 0.29 μm; the thickness of the second metal layer is 0.32 μm; and the thickness of the third metal layer is 4 μm.

5. The bidirectional coupler according to claim 1, characterized in that: The transmission line is U-shaped; the adapter line includes two adapter lines which are spaced apart from each other; the coupling line includes a first coupling line and a second coupling line which are spaced apart from each other; The first coupling line includes a first vertical section and a first U-shaped section extending from one end of the first vertical section and being bent and U-shaped; one end of the first vertical section away from the first U-shaped section is connected to one of the connection holes, and one end of the first U-shaped section away from the first vertical section is connected to one of the adapter lines, and the orthographic projections of the first vertical section and the first U-shaped section to the transmission line are completely located on the transmission line; The second coupling line includes a second vertical section and a second U-shaped section bent and extended from one end of the second vertical section and in a U shape, an inclined section bent and extended from one end of the second U-shaped section away from the second vertical section in a direction close to the second vertical section, and a surrounding section bent and extended from one end of the inclined section away from the second U-shaped section and extending around the inner side of the first U-shaped section and the inner side of the second U-shaped section and in a rectangular structure with an opening; one end of the second vertical section away from the second U-shaped section is connected to the connecting hole, and one end of the surrounding section away from the inclined section is connected to another of the transfer lines, and the orthographic projections of the first vertical section and the inclined section to the transmission line are completely located on the transmission line, the orthographic projection of the part of the second U-shaped section directly opposite to the transmission line to the transmission line is completely located on the transmission line, and the orthographic projection of the part of the surrounding section directly opposite to the transmission line to the transmission line is completely located on the transmission line.

6. The bidirectional coupler according to claim 5, characterized in that The spacing between the first coupling line and the second coupling line is less than 5 μm.

7. A radio frequency module, characterized in that: The radio frequency module includes the bidirectional coupler as described in any one of claims 1 to 6.

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