A duplexer substrate structure and a duplexer

Abstract

The utility model relates to a diplexer technical field provides a kind of diplexer substrate structure and diplexer, wherein diplexer substrate structure includes: substrate component, including first metal layer and second metal layer, second metal layer is below first metal layer;At least one planar inductor, set in first metal layer;Wherein, second metal layer is provided with cutout portion in the projection area of planar inductor, cutout portion is used to reduce the metal area covered by planar inductor in the projection area of second metal layer. By the cutout portion of the projection area corresponding to second metal layer below planar inductor, the coupling with second metal layer below is reduced, the quality factor and inductance of planar inductor are improved, the performance of planar inductor is enhanced, to improve isolation performance, and the structure provided with cutout portion, only need to modify the metal layout of second metal layer, without increasing additional components, with the advantages of simple structure and easy implementation.

Description

Technical Field

[0001] This utility model relates to the field of duplexer technology, and in particular to a duplexer substrate structure and a duplexer. Background Technology

[0002] A duplexer is a key component in an RF front-end module. Its main function is to enable transceivers to share a single antenna and to isolate the transmit (TX) and receive (RX) signals, ensuring that they do not interfere with each other during normal operation. Therefore, high isolation between the transmit and receive ports is one of the core performance indicators for duplexers.

[0003] In existing technologies, an inductor is used to ground the transmitting filter component in the design of a duplexer to enhance the isolation between the transmitting and receiving signal paths. However, parasitic capacitance and electromagnetic coupling exist between the inductor and the metal layer of the substrate. The coupling effect of the inductor can form undesirable signal paths, weaken the effect of the planar inductor itself, and may generate crosstalk between different signal paths, thus limiting the improvement of duplexer isolation.

[0004] Therefore, how to reduce the coupling between the planar inductor and the metal layer of the substrate to improve the isolation performance is an urgent problem to be solved. Utility Model Content

[0005] This invention provides a duplexer substrate structure and a duplexer to solve the defect in the prior art where the coupling effect between the inductor and the metal layer of the substrate leads to the limitation of isolation.

[0006] This utility model provides a duplexer substrate structure, including: A substrate assembly includes a first metal layer and a second metal layer, wherein the second metal layer is located below the first metal layer; At least one planar inductor is disposed on the first metal layer; The second metal layer has a cutout in the projection area of ​​the planar inductor, which is used to reduce the metal area covered by the planar inductor in the projection area of ​​the second metal layer.

[0007] According to the duplexer substrate structure provided by this utility model, the second metal layer is a metal ground layer, and the metal ground layer is adjacent to the first metal layer.

[0008] According to the present invention, in a duplexer substrate structure, at least one edge of the cut-out portion extends to the edge of the second metal layer.

[0009] According to the present invention, the length of the cut portion is in the range of 60% to 80% of the length of the projection area of ​​the planar inductor.

[0010] According to the duplexer substrate structure provided by this utility model, the width of the cut portion is in the range of 60um to 100um.

[0011] According to the duplexer substrate structure provided by this utility model, there is a gap of at least 60 μm between the edge of the planar inductor and the rest of the metal in the first metal layer.

[0012] According to the duplexer substrate structure provided by this utility model, the cutout portion is rectangular.

[0013] According to the duplexer substrate structure provided by this utility model, the second metal layer is provided with an antenna port portion, the second metal layer is provided with an isolation portion surrounding the antenna port portion, and a metal spacer portion is provided between the cut-out portion and the isolation portion, the metal spacer portion being used to prevent communication between the cut-out portion and the isolation portion.

[0014] According to the duplexer substrate structure provided by this utility model, the substrate assembly further includes a third metal layer, which is located below the second metal layer. The third metal layer is provided with a plurality of metal vias, and the cutout portion is located in the projection area of ​​the third metal layer between two adjacent metal vias.

[0015] This utility model also provides a duplexer, including a transmitting filter component, a receiving filter component, and the duplexer substrate structure described above. The transmitting filter component and the receiving filter component are both connected to the substrate assembly, and the transmitting filter component is grounded through the planar inductor.

[0016] This utility model provides a duplexer substrate structure and a duplexer, which have at least the following advantages: A planar inductor is disposed in the first metal layer of the substrate assembly. The planar inductor is formed based on the metal traces of the first metal layer, which helps to reduce the volume of the inductor and integrate it into the first metal layer, eliminating the need for a separate inductor device and simplifying the device structure of the duplexer. Simultaneously, a notch is provided on the second metal layer below the planar inductor. The structure of the notch reduces the metal area in the second metal layer corresponding to the planar inductor, i.e., reduces the metal area of ​​the planar inductor in the projection area of ​​the second metal layer, thereby reducing the parasitic capacitance and electromagnetic coupling between the planar inductor and the lower second metal layer. Therefore, by providing a notch in the projection area of ​​the second metal layer below the planar inductor, the coupling with the lower second metal layer can be reduced, which helps to improve the quality factor and inductance of the planar inductor, enhances the performance of the planar inductor, and thus improves the isolation performance. Furthermore, the structure with the notch only requires modification of the metal layout of the second metal layer, without adding additional components, and has the advantages of simple structure and ease of implementation, while improving isolation performance while maintaining other performance characteristics. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this utility model or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This utility model provides a schematic diagram of the first metal layer in one embodiment of a duplexer substrate structure.

[0019] Figure 2 This utility model provides a schematic diagram of the second metal layer in one embodiment of a duplexer substrate structure.

[0020] Figure 3 This utility model provides a schematic diagram of the third metal layer in one embodiment of a duplexer substrate structure.

[0021] Figure 4 This utility model provides a circuit diagram of one embodiment of a duplexer.

[0022] Figure 5 This utility model provides a test diagram of the isolation performance of one embodiment of a duplexer.

[0023] Figure label: 100: First metal layer; 101: Metal via; 110: Planar inductor; 200: Second metal layer; 210: Cutout; 220: Antenna port; 230: Isolation section; 240: Metal spacer; 300: Third metal layer; 400: Transmit filter assembly; 500: Receive filter assembly. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0025] The following is combined with Figures 1 to 3 This invention describes a duplexer substrate structure, comprising: The substrate assembly includes a first metal layer 100 and a second metal layer 200, wherein the second metal layer 200 is located below the first metal layer 100; At least one planar inductor 110 is disposed on the first metal layer 100; The second metal layer 200 has a cutout 210 in the projection area of ​​the planar inductor 110, and the cutout 210 is used to reduce the metal area covered by the planar inductor 110 in the projection area of ​​the second metal layer 200.

[0026] In the first metal layer 100 of the substrate assembly, a planar inductor 110 is provided. The planar inductor 110 is formed based on the metal traces of the first metal layer 100, which helps to reduce the size of the inductor and integrate it into the first metal layer 100, eliminating the need for an additional separate inductor device and simplifying the device structure of the duplexer. At the same time, a cutout 210 is provided on the second metal layer 200 below the planar inductor 110. The structure of the cutout 210 can reduce the metal area in the second metal layer 200 corresponding to the planar inductor 110, that is, reduce the metal area of ​​the planar inductor 110 in the projection area of ​​the second metal layer 200, thereby reducing the parasitic capacitance and electromagnetic coupling between the planar inductor 110 and the lower second metal layer 200.

[0027] Therefore, by providing a notch 210 in the projection area corresponding to the second metal layer 200 below the planar inductor 110, the coupling with the second metal layer 200 below can be reduced, which is beneficial to improving the quality factor and inductance of the planar inductor 110, enhancing the performance of the planar inductor 110, and thus improving the isolation performance. Moreover, the structure with the notch 210 only requires modification of the metal layout of the second metal layer 200, without the need to add additional components, which has the advantages of simple structure and easy implementation, while improving the isolation performance while keeping other performance unchanged.

[0028] In addition, by providing a corresponding cutout 210 in the second metal layer 200 below the planar inductor 110, this invention has little impact on other performance of the duplexer and can improve the isolation while keeping other performance unchanged.

[0029] It is understood that the planar inductor 110 is formed by the traces of the first metal layer 100. In some embodiments, the planar inductor 110 may specifically be a planar spiral trace. In some embodiments, the planar inductor 110 may be a rectangular, polygonal, or circular structure.

[0030] It should be noted that the projected area of ​​the planar inductor 110 refers to the area occupied by the projection of the outermost edge of the planar inductor 110 onto the second metal layer 200. It can be understood that the shape of the projected area is related to the edge shape of the planar inductor 110. For example, if the edge of the planar inductor 110 is rectangular, polygonal, or circular, the corresponding projected area of ​​the planar inductor 110 on the second metal layer 200 will also be rectangular, polygonal, or circular.

[0031] In some embodiments of this utility model, in addition to the first metal layer 100 and the second metal layer 200, the substrate assembly may also include other metal layers, that is, the substrate assembly may be a double-layer circuit board or a multi-layer circuit board structure.

[0032] In some embodiments of the duplexer substrate structure of this utility model, the second metal layer 200 is a metal ground layer, and the metal ground layer is adjacent to the first metal layer 100.

[0033] The coupling effect between the planar inductor 110 and the metal ground layer is the main source of parasitic capacitance and eddy currents generated by electromagnetic induction. Therefore, the coupling effect between the planar inductor 110 and the metal ground layer is the primary factor affecting isolation. Placing the metal ground layer adjacent to and below the planar inductor 110 (i.e., the second metal layer 200 adjacent to the first metal layer 100 is the metal ground layer) with a notch 210 reduces the coupling effect between the planar inductor 110 and the metal ground layer. This helps reduce parasitic capacitance and eddy currents generated by electromagnetic induction between the planar inductor 110 and the metal ground layer, directly suppressing the main factor affecting isolation. Simultaneously, the proximity of the planar inductor 110 to the metal ground layer reduces the intensity of the downward electromagnetic effects generated by the planar inductor 110. In other words, the metal ground layer can shield the planar inductor 110 from electromagnetic interference to other metal layers or other devices below, thus improving overall performance.

[0034] It should be noted that in some embodiments of this utility model, the second metal layer 200 may not be a ground layer, but a signal layer or power layer, etc. The structure with the notch 210 on the second metal layer 200 can also reduce the coupling between the planar inductor 110 and the second metal layer 200, thus improving isolation. However, having the second metal layer 200 as a ground layer directly reduces the main coupling effect between the planar inductor 110 and ground, and the shielding effect of the ground layer can reduce the electromagnetic influence of the planar inductor 110 on other layers or devices. In other words, having the second metal layer 200 as a ground layer is a preferred implementation, but it is not limited to this. The following description assumes the second metal layer 200 is a ground layer.

[0035] refer to Figure 1 and Figure 2 In the embodiment where the second metal layer 200 is a metal ground layer, one end of the planar inductor 110 is provided with a connection via to connect to the metal ground layer, and the other end of the planar inductor 110 can be used to connect to the transmitting filter component 400 of the duplexer so that the transmitting filter component 400 is grounded through the inductor, thereby increasing the isolation between the transmitting filter component 400 and the receiving filter component.

[0036] refer to Figure 2 In some embodiments of the duplexer substrate structure of this utility model, at least one edge of the cutout 210 extends to the edge of the second metal layer 200.

[0037] The edge of the cutout 210 extends to the edge of the second metal layer 200, that is, the cutout 210 forms a "U" or "L" shaped opening. The edge of the cutout 210 does not have a closed annular metal, which can prevent the planar inductor 110 from forming an eddy current loop on the second metal layer 200 due to electromagnetic induction, further reducing the coupling effect between the planar inductor 110 and the lower second metal layer 200, thereby helping to further improve the isolation of the duplexer.

[0038] Compared to setting a closed "U-shaped" structure within the second metal layer 200, the metal surrounding the "U-shaped" structure remains closed and connected. Under the electromagnetic effect of the planar inductor 110, a current loop may be formed around the cut. However, the structure of this invention, where the cut portion 210 extends to the edge of the second metal layer 200, eliminates the possibility of such a current loop from a physical structural perspective, making the decoupling effect between the planar inductor 110 and the second metal layer 200 more significant.

[0039] refer to Figure 1 and Figure 2 In some embodiments of the duplexer substrate structure of this utility model, the length of the cutout 210 is in the range of 60% to 80% of the length of the projection area of ​​the planar inductor 110.

[0040] Length of the incision 210 ( Figure 2 The length of the cut (in the left-right direction) is directly related to the metal area removed from the projection area of ​​the second metal layer 200 in the planar inductor 110, affecting the decoupling effect. When the second metal layer 200 is a metal ground layer, the length of the cut also affects the planar integrity of the metal ground layer. By controlling the cut length within 60% to 80% of the projection area length of the planar inductor 110, it is possible to ensure that the cut portion 210 covers most of the area of ​​the planar inductor 110, minimize the corresponding metal area of ​​the planar inductor 110, effectively reduce parasitic capacitance and electromagnetic coupling, thereby improving the isolation effect, while retaining an appropriate ground plane area to maintain its good shielding performance. This achieves a balance between improving isolation and maintaining the shielding performance of the metal ground layer, which is beneficial to making the overall performance of the duplexer better.

[0041] refer to Figure 2 In some embodiments of the duplexer substrate structure of this utility model, the width of the cutout 210 is in the range of 60um to 100um.

[0042] Width of cut 210 ( Figure 2The vertical direction (in the second metal layer 200) determines the spacing between the disconnected metals. When the second metal layer 200 is a metal ground layer, it determines the physical spacing between the two parts of the metal ground layer. This spacing directly affects the capacitance effect between the gaps and the ability to cross high-frequency signals. By making the width of the cutout 210 within the range of 60µm to 100µm, the coupling effect between the planar inductor 110 and the underlying metal ground layer can be effectively reduced, improving isolation, without significantly reducing the area of ​​the metal ground layer.

[0043] It is understandable that if the length or width of the cutout 210 is too small, the decoupling effect will be insignificant; if the length and width are too large, it may excessively damage the integrity of the ground plane, affecting the shielding effect. In this invention, by keeping the width of the cutout 210 within the range of 60µm to 100µm while controlling the cutout length within the range of 60% to 80% of the length of the projected area of ​​the planar inductor 110, the isolation effect and the shielding effect of the metal ground layer can be balanced, which is beneficial to improving the overall stability.

[0044] refer to Figure 1 In some embodiments of the duplexer substrate structure of this utility model, there is a gap of at least 60 μm between the edge of the planar inductor 110 and the rest of the metal in the first metal layer 100.

[0045] The planar inductor 110 not only has a coupling effect with the second metal layer 200, which is on a different layer, but also has a coupling effect with other metals in the same layer, namely the first metal layer 100. By maintaining a distance of at least 60 μm between the edge of the planar inductor 110 and the other metals in the first metal layer 100, crosstalk between metals in the same layer can be effectively reduced, which helps to reduce energy leakage of the planar inductor 110 due to electromagnetic effects and ensures the isolation performance of the planar inductor 110.

[0046] In some embodiments of this utility model, when there is sufficient planar space, a gap of more than 80 μm is left between the edge of the planar inductor 110 and the metal in the same layer to obtain better isolation performance. When planar space is limited, a gap of at least 60 μm should be left to ensure the performance of the planar inductor 110 and reduce the impact of signal crosstalk.

[0047] refer to Figure 2 In some embodiments of the duplexer substrate structure of this utility model, the cutout portion 210 is rectangular.

[0048] The rectangular shape of the cutout 210 facilitates precise design of its dimensions, makes it easier to predict and optimize the actual decoupling effect and the degree of improvement in isolation brought about by the cutout 210. At the same time, the rectangular shape of the cutout 210 helps to simplify the design and manufacturing process, ensure the accuracy and consistency of processing, and help to reduce the implementation costs of design and production.

[0049] refer to Figure 2 In some embodiments of the duplexer substrate structure of this utility model, the second metal layer 200 is provided with an antenna port portion 220, and the second metal layer 200 is provided with an isolation portion 230 surrounding the antenna port portion 220. A metal spacer portion 240 is provided between the cut portion 210 and the isolation portion 230, and the metal spacer portion 240 is used to prevent communication between the cut portion 210 and the isolation portion 230.

[0050] The substrate assembly serves as the foundation for connections between components and also as the basis for connecting the duplexer to the antenna and RF circuitry. The second metal layer 200 of the substrate assembly has an antenna port 220 for connection to the antenna. To avoid affecting antenna performance, an isolation portion 230 is provided around the antenna port 220 to achieve electrical isolation. A metal spacer 240 is provided to separate the notch 210 from the isolation portion 230, preventing communication between them and avoiding an excessively large opening around the antenna port 220, thus preventing the introduction of unexpected resonances or new coupling paths. In this way, the independence and effectiveness of the functions of the notch 210 and the isolation portion 230 are ensured—that is, the decoupling effect of the notch 210 on the planar inductor 110 is guaranteed—while simultaneously ensuring antenna performance.

[0051] From another perspective, the metal spacer 240 is designed to prevent the cutout 210 from being too long and to prevent the cutout 210 from extending directly to the isolation portion 230 around the antenna port portion 220. In other words, the cutout 210 cannot penetrate into the isolation portion 230, thereby avoiding affecting the performance of the antenna. Therefore, there will be a portion of metal between the cutout 210 and the isolation portion 230, forming the metal spacer 240.

[0052] refer to Figure 3 In some embodiments of the duplexer substrate structure of this utility model, the substrate assembly further includes a third metal layer 300, which is located below the second metal layer 200. The third metal layer 300 is provided with a plurality of metal vias 101, and the cutout portion 210 is located between two adjacent metal vias 101 in the projection area of ​​the third metal layer 300.

[0053] The position of the cutout 210 in the second metal layer 200 is designed between adjacent metal vias 101 on the third metal layer 300. That is, the projection area of ​​the cutout 210 on the third metal layer 300 will not cover the metal vias 101, so as to avoid the structure with the cutout 210 affecting the metal vias 101, which is beneficial to improving the reliability of the structure.

[0054] It is understandable that the metal via 101 is used to connect the metal of the third metal layer 300 to the metal of other layers to achieve the required electrical connection. Besides the third metal layer 300 having the metal via 101, other metal layers may also have metal vias 101 according to structural and electrical connection requirements. When the second metal layer 200 is a metal ground layer, the metal via 101 connected to the second metal layer 200 can be called a grounding via. When one end of the planar inductor 110 is grounded, such as... Figure 1 and Figure 2 As shown, a grounding via is provided between one end of the planar inductor 110 and the metal ground layer.

[0055] In some embodiments, the third metal layer 300 may be a bottom layer, and the second metal layer 200 may be a metal ground layer. The metal ground layer also serves as an isolation layer. By utilizing the shielding effect of the metal ground layer, the first metal layer 100 and the third metal layer 300 are isolated, which helps to reduce the influence of the planar inductor 110 in the first metal layer 100 on the third metal layer 300.

[0056] The following describes a duplexer provided by this utility model. The duplexer described below and the duplexer substrate structure described above can be referred to in correspondence.

[0057] refer to Figure 4 The present invention provides a duplexer, including a transmitting filter component 400, a receiving filter component 500, and a duplexer substrate structure as described above. The transmitting filter component 400 and the receiving filter component 500 are both connected to the substrate assembly, and the transmitting filter component 400 is grounded through the planar inductor 110.

[0058] In the duplexer, the transmitting filter component 400 is grounded through the planar inductor 110. The planar inductor 110 and the capacitor or parasitic capacitance in the transmitting filter component 400 form a resonant circuit. The resonant frequency of the resonant circuit corresponds to the noise in the receiving frequency band, that is, it provides a grounded low impedance path for the noise in the receiving frequency band, avoids the noise in the receiving frequency band from affecting the transmitting path, and thus enhances the isolation between the transmitting path and the receiving path in the duplexer.

[0059] Furthermore, a planar inductor 110 is provided in the first metal layer 100 of the substrate assembly. The planar inductor 110 is formed based on the metal traces of the first metal layer 100, which helps to reduce the volume of the inductor and integrate it into the first metal layer 100, eliminating the need for additional separate inductor devices and simplifying the device structure of the duplexer.

[0060] Meanwhile, a cutout 210 is provided on the second metal layer 200 below the planar inductor 110. The structure of the cutout 210 can reduce the metal area in the second metal layer 200 corresponding to the planar inductor 110, that is, reduce the metal area of ​​the planar inductor 110 in the projection area of ​​the second metal layer 200, thereby reducing the parasitic capacitance and electromagnetic coupling between the planar inductor 110 and the lower second metal layer 200.

[0061] Therefore, by providing a notch 210 in the projection area corresponding to the second metal layer 200 below the planar inductor 110, the coupling with the second metal layer 200 below can be reduced, which is beneficial to improving the quality factor and inductance of the planar inductor 110, enhancing the performance of the planar inductor 110, and thus improving the isolation performance. Moreover, the structure with the notch 210 only requires modification of the metal layout of the second metal layer 200, without the need to add additional components, which has the advantages of simple structure and easy implementation, while improving the isolation performance while keeping other performance unchanged.

[0062] In some embodiments of this utility model, reference is made to Figure 4 The diagram shows the circuit schematic of a duplexer, where ANT is the antenna connection terminal, TX is the RF transmit connection terminal, and RX is the RF receive connection terminal. The transmit filter component 400 may include multiple capacitors and resistors connected in series and parallel to form a transmit filter, allowing signals in the transmit frequency band to be transmitted from the RF transmit connection terminal TX to the antenna. The transmit filter component 400 is grounded through inductors L1 and L2, which can be the planar inductors 110 disposed in the first metal layer 100 as described above. The receive filter component 500 may include capacitors, surface acoustic wave filters, and resistors to form a receive filter, allowing signals in the receive frequency band to be transmitted from the antenna to the RF receive connection terminal RX.

[0063] Understandably, the capacitors and resistors of the transmitting filter component 400 are mounted on the substrate assembly. Similarly, the capacitors, surface acoustic wave filters, and resistors of the receiving filter component 500 are also mounted on the substrate assembly. Furthermore, each component achieves its function through multiple metal layers within the substrate assembly. Figure 4 The circuit connections are shown.

[0064] To more intuitively understand the effect of the structure with the notch 210 in this utility model on improving isolation performance, refer to... Figure 5 , Figure 5 The graph shows the isolation performance curves. The gray curve represents the optimized isolation performance of the structure without the notch 210, while the black curve represents the optimized isolation performance of the structure with the notch 210. It can be seen that the black curve is very close to the gray curve, but the black curve exhibits superior isolation performance, particularly between 1.85 GHz and 1.9 GHz. Based on the tests, under the condition of obtaining the same inductance, the structure with the notch 210 improves the duplexer isolation performance by approximately 1 dB to 2 dB, while increasing the perceived inductance of the planar inductor by 0.2 nH.

[0065] In the description of this utility model, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0066] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A duplexer substrate structure, characterized in that, include: The substrate assembly includes a first metal layer (100) and a second metal layer (200), wherein the second metal layer (200) is located below the first metal layer (100); At least one planar inductor (110) is disposed on the first metal layer (100). The second metal layer (200) has a cutout (210) in the projection area of ​​the planar inductor (110), and the cutout (210) is used to reduce the metal area covered by the planar inductor (110) in the projection area of ​​the second metal layer (200).

2. The duplexer substrate structure according to claim 1, characterized in that, The second metal layer (200) is a metal ground layer, which is adjacent to the first metal layer (100).

3. The duplexer substrate structure according to claim 1, characterized in that, At least one edge of the cut (210) extends to the edge of the second metal layer (200).

4. The duplexer substrate structure according to claim 1, characterized in that, The length of the cut (210) is in the range of 60% to 80% of the length of the projection area of ​​the planar inductor (110).

5. The duplexer substrate structure according to claim 4, characterized in that, The width of the cut (210) is in the range of 60um to 100um.

6. The duplexer substrate structure according to claim 1, characterized in that, There is a gap of at least 60 μm between the edge of the planar inductor (110) and the rest of the metal in the first metal layer (100).

7. A duplexer substrate structure according to any one of claims 1 to 6, characterized in that, The cut portion (210) is rectangular.

8. A duplexer substrate structure according to any one of claims 1 to 6, wherein the second metal layer (200) is provided with an antenna port portion (220), the second metal layer (200) is provided with an isolation portion (230) surrounding the antenna port portion (220), a metal spacer portion (240) is provided between the cut portion (210) and the isolation portion (230), and the metal spacer portion (240) is used to prevent communication between the cut portion (210) and the isolation portion (230).

9. A duplexer substrate structure according to any one of claims 1 to 6, characterized in that, The substrate assembly further includes a third metal layer (300) located below the second metal layer (200). The third metal layer (300) is provided with a plurality of metal vias (101). The cutout (210) is located between two adjacent metal vias (101) in the projection area of ​​the third metal layer (300).

10. A duplexer, characterized in that, The system includes a transmit filter assembly (400), a receive filter assembly (500), and a duplexer substrate structure as described in any one of claims 1 to 9, wherein the transmit filter assembly (400) and the receive filter assembly (500) are both connected to the substrate assembly, and the transmit filter assembly (400) is grounded through the planar inductor (110).

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