Bidirectional coupler

Abstract

The invention provides a bidirectional coupler and a radio frequency module. The bidirectional coupler comprises a silicon oxide layer, an insulating layer, a first metal layer, a second metal layer, a third metal layer, 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 connecting hole penetrating from the first metal layer to the second metal layer, and a connecting line, wherein the silicon oxide layer, the insulating layer, the first metal layer, the second metal layer and the third metal layer are stacked and fixed in sequence. 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; the width of the coupling line is smaller than 10 micrometers, the distance between the patch cord and the transmission line is smaller than 5 micrometers, and the distance between the patch cord and the coupling line is smaller than 5 micrometers. The coupling degree and the isolation degree of the bidirectional coupler can be improved, the insertion loss of the bidirectional coupler is reduced, large broadband and miniaturization are achieved, and meanwhile high-density integration can be achieved in a radio frequency assembly.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless communications, and in particular to a bidirectional coupler. Background Art

[0002] In wireless communication systems, efficient transmission and accurate monitoring of RF signals are key factors in ensuring system performance. As an important RF component in communication systems, bidirectional couplers are now widely used in signal monitoring, power measurement, antenna matching and other fields.

[0003] Bidirectional couplers are usually implemented using microstrip or waveguide technology, but they often face problems such as high insertion loss, insufficient isolation, and large size in high-frequency and broadband applications, making it difficult to meet the needs of high-performance RF components.

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

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

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

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions: 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 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 switching line buried and fixed in the first metal layer and insulated from the first metal layer. The metal layer is provided with an insulated coupling line, 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.

[0008] Preferably, the width of the coupling line is 6 μm.

[0009] Preferably, the first metal layer and the second metal layer are both made of copper; and the third metal layer is made of aluminum.

[0010] Preferably, 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.

[0011] Preferably, the transmission line is U-shaped; the adapter line includes two and is spaced apart from each other; the coupling line includes a first coupling line and a second coupling line 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.

[0012] Preferably, a distance between the first coupling line and the second coupling line is less than 5 μm.

[0013] In a second aspect, the present invention provides a radio frequency module, which includes the bidirectional coupler as described above.

[0014] Compared with the prior art, the bidirectional coupler in the present invention optimizes the arrangement and connection method of the silicon oxide layer, the insulating layer, the first metal layer, the second metal layer, the third metal layer, the transmission line, the adapter line, the coupling line, the connection hole and the connection line, and limits the positive projection area of ​​the first metal layer on the third metal layer to 30-40% of the side area of ​​the third metal layer opposite to the first metal layer, and the width of the coupling line is less than 10μm, thereby improving the coupling and isolation of the bidirectional coupler, reducing its insertion loss, and achieving large bandwidth and miniaturization. At the same time, high-density integration can be achieved in the radio frequency component, so that the overall performance can be improved after it is applied to the radio frequency component. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be described in detail below in conjunction with the accompanying drawings. The above and other aspects of the present invention will become clearer and easier to understand through the detailed description made in conjunction with the following drawings. In the accompanying drawings: Figure 1 A schematic diagram of a transmission line, a transfer line, a coupling line, a connection hole and a three-dimensional structure after the connection holes are connected in a bidirectional coupler provided in an embodiment of the present invention; Figure 2 A top view of a transmission line, a transfer line, a coupling line, a connection hole, and the connection holes in a bidirectional coupler according to an embodiment of the present invention; Figure 3 A transmission line, a transfer line, a coupling line, a connection hole and a side view after the connection holes are connected in a bidirectional coupler provided in an embodiment of the present invention; Figure 4 A schematic diagram of stacking of a bidirectional coupler provided in an embodiment of the present invention; Figure 5 A diagram showing simulation results of the coupling coefficient and isolation coefficient of a bidirectional coupler provided in an embodiment of the present invention.

[0016] Among them, 100, bidirectional coupler; 1, silicon oxide layer; 2, insulating layer; 3, first metal layer; 4, second metal layer; 5, third metal layer; 6, transmission line; 7, adapter line; 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, connecting hole; 91, first connecting hole; 92, second connecting hole; 10, connecting line. DETAILED DESCRIPTION

[0017] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of the present application; the terms used in the specification of the application herein are only for the purpose of describing specific embodiments and are not intended to limit the present application; the terms "including" and "having" and any variations thereof in the specification and claims of the present application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of the present application or the above-mentioned drawings are used to distinguish different objects, not to describe a specific order.

[0018] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] Embodiment 1 The embodiment of the present invention provides a bidirectional coupler 100, which includes a silicon oxide layer 1, an insulating layer 2 forming one side of the silicon oxide layer 1, a first metal layer 3 forming a side of the insulating layer 2 away from the silicon oxide layer 1, a second metal layer 4 forming a 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 a 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 switching line 7 buried and fixed in the second metal layer 4 and insulated from the second metal layer 4, a coupling line 8 buried and fixed in the first metal layer 3 and insulated from the first metal layer 3, a connection hole 9 and a connection line 10 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.

[0021] Among them, the coupling line 8 is coupled with the transmission line 6, the two ends of the adapter line 7 are respectively connected to the transmission line 6 and the coupling line 8, the two ends of the connection hole 9 are respectively connected to the transmission line 6 and the coupling line 8, and the two ends of the transmission line 6 serve as the signal input end and the signal output end of the bidirectional coupler 100; the connection hole 9 and the connection line 10 respectively include two, one end of each of the two connection lines 10 is respectively connected to the two connection holes 9, and the other end of each of the two connection lines 10 serves as the isolation end and the coupling end of the bidirectional coupler 100.

[0022] The area of ​​the orthographic projection of the first metal layer 3 on the third metal layer 5 is 30-40% of the area of ​​the third metal layer 5 on the side close to the first metal layer 3 .

[0023] The first metal layer 3 and the second metal layer 4 are both made of copper (Cu), and the third metal layer 5 is made of aluminum (Al). Of course, the materials of the first metal layer 3, the second metal layer 4 and the third metal layer 5 can also be adaptively modified according to actual needs.

[0024] The thickness of the first metal layer 3 is 0.29 μm, the thickness of the second metal layer 4 is 0.32 μm, and the thickness of the third metal layer 5 is 4 μm. Of course, the thickness of the first metal layer 3 and the third metal layer 5 can be adaptively improved according to actual needs.

[0025] In this embodiment, Figure 1 and Figure 2 As shown, the transmission line 6 is U-shaped; the adapter line 7 includes two mutually spaced-apart coupling lines; the coupling line 8 includes a first coupling line 81 and a second coupling line 82 mutually spaced-apart coupling lines.

[0026] The first coupling line 81 includes a first vertical section 811 and a first U-shaped section 812 which 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 away from the first U-shaped section 812 is connected to one of the connecting holes 9, and one end of the first U-shaped section 812 away from the first vertical section 811 is connected to one of the adapter lines 7, and the positive projections of the first vertical section 811 and the first U-shaped section 812 to the transmission line 6 are completely located on the transmission line 6.

[0027] The second coupling line 82 includes a second vertical section 821, a second U-shaped section 822 extending from one end of the second vertical section 821 and being bent and extending in a U shape, an inclined section 823 extending from one end of the second U-shaped section 822 away from the second vertical section 821 and bending inwardly toward the second vertical section 821, and a surrounding section 824 extending from one end of the inclined section 823 away from the second U-shaped section 822 and surrounding the inner side of the first U-shaped section 812 and the inner side of the second U-shaped section 822 and having an opening and being in a rectangular structure. ; One end of the second vertical segment 821 away from the second U-shaped segment 822 is connected to the connecting hole 9, and one end of the surrounding segment 824 away from the inclined segment 823 is connected to another adapter line 7. The orthographic projections of the first vertical segment 811 and the inclined segment 823 to the transmission line 6 are completely located on the transmission line 6, the orthographic projection of the part of the second U-shaped segment 822 facing the transmission line 6 to the transmission line 6 is completely located on the transmission line 6, and the orthographic projection of the part of the surrounding segment 824 facing the transmission line 6 to the transmission line 6 is completely located on the transmission line 6.

[0028] The width of the coupling line 8 is less than 10 μm, and the spacing 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 spacing between the first coupling line 81 and the second coupling line 82 is less than 3 μm.

[0029] In addition, the area of ​​the first coupling line 81 and the second coupling line 82 projected onto the transmission line 6 accounts for at least 30% of the area of ​​the side surface of the transmission line 6, such as 60-70%, 50%, 80%, etc.

[0030] In this embodiment, Figure 1 and Figure 3 As shown, the connecting hole 9 and the connecting line 10 include two respectively, one end of the two connecting lines 10 is connected to the connecting hole 9 respectively, and the other ends of the two connecting lines 10 serve as the isolation end and the coupling end of the bidirectional coupler 100 respectively, 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 connected to the two connecting holes 9 respectively.

[0031] The portion of the connection hole 9 located in the first metal layer 3 is a first connection hole 91 , and the portion located in the second metal layer 4 is a second connection hole 92 .

[0032] For the sake of convenience, Figure 4 The transmission line 6, the adapter line 7 and the coupling line 8 are represented by blocks, and the connection method is not shown.

[0033] In the bidirectional coupler 100 of the present 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 jumps layers through the adapter line 7, and the adapter line 7 is located on 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 select 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 connecting lines 10 will connect various selection switches, it will not affect the performance of the bidirectional coupler 100, and the connecting line 10 and the coupling line 8 will change layers through the first connection hole 91.

[0034] The bidirectional coupler 100 in this embodiment is parallel coupled by the third metal layer 5 and the first metal layer 3, 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 in this embodiment operates in the frequency band of 1.3-2.7 GHz, a higher coupling coefficient and isolation coefficient can be achieved.

[0035] The bidirectional coupler 100 in this embodiment is bidirectional. Figure 2 and Figure 5 As shown, in reverse coupling, 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, and 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; in forward coupling, 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, and 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.

[0036] Combination Figure 5As shown, the bidirectional coupler 100 operates in the 1.3-2.7GHz frequency band. During reverse coupling, the curve of the reverse coupling coefficient is approximately consistent, with a deviation of plus or minus 0.2dB, and the coupling coefficient is between 22-28.7dB; during forward coupling, the forward isolation coefficient is 1.6-2.3dB better than the reverse isolation coefficient, the forward isolation coefficient is between 48.6-63.2dB, and the reverse isolation coefficient is between 47.0-60.8dB. According to calculations, within this frequency band, the forward directivity can be 26.4-34.4dB, and the reverse directivity can be 24.8-32.2dB. It can be seen that the bidirectional coupler 100 of this embodiment can achieve excellent coupling coefficient and directivity.

[0037] Compared with the prior art, the bidirectional coupler 100 in this embodiment optimizes the arrangement and connection 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 adapter line 7, the coupling line 8, the connection hole 9 and the connection line 10, and limits the positive projection area of ​​the first metal layer 3 on the third metal layer 5 to 30-40% of the side area of ​​the third metal layer 5 opposite to the first metal layer 3, and the width of the coupling line 8 is less than 10μm, thereby improving the coupling and isolation of the bidirectional coupler 100, reducing its insertion loss, and achieving large bandwidth and miniaturization. At the same time, high-density integration can be achieved in the RF component, so that the overall performance can be improved after it is applied to the RF component.

[0038] Embodiment 2 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 effect achieved by the bidirectional coupler 100 in the above embodiment 1, which will not be described in detail here.

[0039] It should be noted that the various embodiments described above with reference to the accompanying drawings are only used to illustrate the present invention rather than to limit the scope of the present invention. Those skilled in the art should understand that any modification or equivalent substitution of the present invention without departing from the spirit and scope of the present invention should be included within the scope of the present invention. In addition, unless otherwise indicated by the context, words appearing in the singular include the plural form, and vice versa. In addition, unless otherwise specified, all or part of any embodiment may 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, wherein: 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.

Images