Filter

Abstract

The utility model discloses a filter, which comprises a substrate and a capacitor positioned on one side of the substrate, the capacitor comprises a first electrode substrate, a second electrode substrate, a third electrode substrate, a first dielectric layer, a second dielectric layer, a first connecting part and a second connecting part, the first dielectric layer is located on the side, away from the substrate, of the first electrode substrate, the second electrode substrate is located on the side, away from the substrate, of the first dielectric layer, the second dielectric layer is located on the side, away from the substrate, of the second electrode substrate, and the third electrode substrate is located on the side, away from the substrate, of the second dielectric layer; the first connecting part is connected with the first electrode substrate and the third electrode substrate, and the second connecting part is connected with the second electrode substrate. By adopting the technical scheme, the bandwidth of the filter is increased, and high-performance capacitance regulation and control of the filter are realized.

Description

Technical Field

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

[0002] Radio frequency (RF) filters are core components used in the RF front-end of wireless communication. Thin-film bulk acoustic wave (BAWR) resonators are key and fundamental units in the construction of RF filters. Currently, the resonators used in the RF market are surface acoustic wave (SAWR) resonators and bulk acoustic wave (BAWR) resonators. Among them, BAWR is gradually becoming the market mainstream due to its advantages of high resonant frequency, high quality factor, high electromechanical coupling coefficient, high power capacity, low loss, small size, and compatibility with CMOS semiconductor processes.

[0003] Due to the limitations of the electromechanical coupling coefficient of the resonator material, the bandwidth of bulk acoustic wave (BAW) filters is relatively small. In practical applications, passive components such as external capacitors or inductors are usually added as matching circuits or to increase the bandwidth of the filter and adjust its filtering characteristics. Currently, integrated capacitor resonators on the market mostly add capacitor structures to the side of the resonator, directly integrating the capacitor on the chip. Compared with external capacitors, this results in a smaller area, avoids the need for additional lead-out paths, and avoids corresponding electrical parasitics, thereby improving the performance of the resonator and filter. However, the capacitance performance of integrated capacitors is relatively low, making it difficult to achieve high capacitance levels, and the adjustment effect on the resonator is poor. Utility Model Content

[0004] This invention provides a filter that increases capacitance and improves the filter's adjustment performance.

[0005] According to a first aspect of the present invention, a filter is provided, comprising: a substrate and a capacitor located on one side of the substrate;

[0006] The capacitor includes a first electrode substrate, a second electrode substrate, a third electrode substrate, a first dielectric layer, a second dielectric layer, a first connecting portion, and a second connecting portion;

[0007] The first dielectric layer is located on the side of the first electrode substrate away from the substrate, the second electrode substrate is located on the side of the first dielectric layer away from the substrate, the second dielectric layer is located on the side of the second electrode substrate away from the substrate, and the third electrode substrate is located on the side of the second dielectric layer away from the substrate.

[0008] The first connecting portion is connected to the first electrode substrate and the third electrode substrate respectively, and the second connecting portion is connected to the second electrode substrate.

[0009] Optionally, the capacitor further includes a fourth electrode substrate and a third dielectric layer;

[0010] The third dielectric layer is located on the side of the third electrode substrate away from the substrate, and the fourth electrode substrate is located on the side of the third dielectric layer away from the substrate;

[0011] The second connecting portion is also connected to the fourth electrode substrate.

[0012] Optionally, along the thickness direction of the substrate, the thickness of the first dielectric layer is d1, and the thickness of the second dielectric layer is d2; wherein, 0.8≤d1 / d2≤1.2.

[0013] Optionally, along the thickness direction of the substrate, the thickness of the first dielectric layer is d1, the thickness of the second dielectric layer is d2, and the thickness of the third dielectric layer is d3; wherein, 0.8≤d1 / d2≤1.2, 0.8≤d2 / d3≤1.2.

[0014] Optionally, along the thickness direction of the substrate, the first electrode substrate and the second electrode substrate have a first overlapping region, and the second electrode substrate and the third electrode substrate have a second overlapping region;

[0015] The orthographic projection of the first dielectric layer onto the plane where the substrate is located overlaps the orthographic projection of the first overlapping region onto the plane where the substrate is located;

[0016] The orthographic projection of the second dielectric layer onto the plane of the substrate covers the orthographic projection of the second overlapping region onto the plane of the substrate.

[0017] Optionally, along the thickness direction of the substrate, the first electrode substrate and the second electrode substrate have a first overlapping region, and the second electrode substrate and the third electrode substrate have a second overlapping region;

[0018] The orthographic projection of the first overlapping region onto the plane where the substrate is located covers the orthographic projection of the first dielectric layer onto the plane where the substrate is located;

[0019] The orthographic projection of the second overlapping region onto the plane of the substrate covers the orthographic projection of the second dielectric layer onto the plane of the substrate.

[0020] Optionally, along the thickness direction of the substrate, the third electrode substrate and the fourth electrode substrate have a third overlapping region;

[0021] The orthographic projection of the third dielectric layer onto the plane of the substrate covers the orthographic projection of the third overlapping region onto the plane of the substrate.

[0022] Optionally, along the thickness direction of the substrate, the third electrode substrate and the fourth electrode substrate have a third overlapping region;

[0023] The orthographic projection of the third overlapping region onto the plane of the substrate covers the orthographic projection of the third dielectric layer onto the plane of the substrate.

[0024] Optionally, the filter may further include a resonator;

[0025] The resonator includes a fifth electrode substrate, a piezoelectric layer, and a sixth electrode substrate; the sixth electrode substrate is connected to the first connection portion.

[0026] The piezoelectric layer is located on the side of the fifth electrode substrate away from the substrate, and the sixth electrode substrate is located on the side of the piezoelectric layer away from the substrate;

[0027] A groove is provided in the surface of the substrate near the resonator, and the resonator at least partially overlaps the groove along the thickness direction of the substrate.

[0028] Optionally, the fifth electrode substrate is disposed in the same layer as the second electrode substrate;

[0029] The sixth electrode substrate is disposed on the same layer as the third electrode substrate.

[0030] The filter provided in this embodiment of the utility model has a structure in which a first electrode substrate, a first dielectric layer, a second electrode substrate, a second dielectric layer and a third electrode substrate are stacked sequentially on one side of the substrate. The first electrode substrate and the third electrode substrate are connected by a first connecting part, and the second electrode substrate is reused to form two parallel sub-capacitors. The capacitance of the capacitor is the sum of the capacitances of the parallel sub-capacitors, which increases the bandwidth of the filter. The filter can be adjusted over a wider range of capacitances, and high-performance capacitance control of the filter is achieved.

[0031] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this utility model, nor is it intended to limit the scope of this utility model. Other features of this utility model will become readily apparent from the following description. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1This is a schematic diagram of the structure of a filter provided in an embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of another filter structure provided in an embodiment of the present invention;

[0035] Figure 3 This is a schematic diagram of another filter structure provided in an embodiment of the present invention;

[0036] Figure 4 This is a schematic diagram of another filter structure provided in an embodiment of the present invention;

[0037] Figure 5 This is a schematic diagram of another filter structure provided in an embodiment of the present invention;

[0038] Figure 6 This is a schematic diagram of another filter structure provided in an embodiment of the present invention;

[0039] Figure 7 This is a schematic diagram of the structure of another filter provided in this embodiment of the utility model. Detailed Implementation

[0040] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0041] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the utility model described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0042] It should be understood that the various forms of the process shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this utility model can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this utility model can be achieved, and this is not limited herein.

[0043] Radio frequency (RF) filters are key components in modern wireless communication equipment, and their performance directly affects signal transmission quality and system efficiency. Thin-film bulk acoustic wave (TIW) resonators are crucial and fundamental units in RF filters. Integrating capacitor structures within the filter can improve and adjust various aspects of its performance. Conventional filter capacitors are mainly of two types: integrated passive device (IPD) capacitors and metal-insulator-metal (MIM) capacitors. Due to the presence of parasitics and relatively large size of IPD capacitors in high-frequency applications, MIM capacitor structures are commonly used in the RF and microwave fields. A MIM capacitor structure consists of a lower electrode, a upper electrode, a dielectric layer, and a substrate. The dielectric layer is located on the side of the lower electrode furthest from the substrate, and the upper electrode is located on the side of the dielectric layer furthest from the substrate. When the materials of the upper and lower electrodes are the same, the dielectric constant of the capacitor structure is ε0, the area of ​​the upper and lower electrodes facing each other is s0, and the thickness of the dielectric layer is d0. Then, according to the formula for calculating the capacitance value, the capacitance value of the capacitor structure is c0 = ε0 * s0 / d0. Due to the space constraints of integrating the capacitor in the RF filter, the area of ​​the capacitor is small. As a result, with the dielectric layer thickness remaining unchanged, the capacitance integrated in the RF filter is smaller than that of an external capacitor, and the capacitance performance is relatively low. It is difficult to achieve a high level of capacitance, so the adjustment effect on the resonator in the filter is poor.

[0044] To solve the above problems, Figure 1 This is a schematic diagram of the structure of a filter provided in an embodiment of this utility model. Figure 1 As shown, the filter provided in this embodiment of the present invention includes: a substrate 1 and a capacitor 100 located on one side of the substrate 1; the capacitor 100 includes a first electrode substrate 2, a second electrode substrate 3, a third electrode substrate 4, a first dielectric layer 5, a second dielectric layer 6, a first connecting portion 7, and a second connecting portion 8; the first dielectric layer 5 is located on the side of the first electrode substrate 2 away from the substrate 1, the second electrode substrate 3 is located on the side of the first dielectric layer 5 away from the substrate 1, the second dielectric layer 6 is located on the side of the second electrode substrate 3 away from the substrate 1, and the third electrode substrate 4 is located on the side of the second dielectric layer 6 away from the substrate 1; the first connecting portion 7 is connected to the first electrode substrate 2 and the third electrode substrate 4 respectively, and the second connecting portion 8 is connected to the second electrode substrate 3.

[0045] Specifically, the first dielectric layer 5 is located on the side of the first electrode substrate 2 away from the substrate 1, and the second electrode substrate 3 is located on the side of the first dielectric layer 5 away from the substrate 1. With this arrangement, the first electrode substrate 2, the first dielectric layer 5, and the second electrode substrate 3 constitute a first sub-capacitor. The first electrode substrate 2 can serve as the lower electrode of the first sub-capacitor, and the second electrode substrate 3 can serve as the upper electrode of the first sub-capacitor. The capacitance value of the first sub-capacitor is C1. The third electrode substrate 4 is located on the side of the second dielectric layer 6 away from the substrate 1. The second electrode substrate 3, the second dielectric layer 6, and the third electrode substrate 4 constitute a second sub-capacitor. The second electrode substrate 3 can be reused as the lower electrode of the second sub-capacitor, and the third electrode substrate 4 can serve as the upper electrode of the second sub-capacitor. The capacitance value of the second sub-capacitor is C2. The first connecting part 7 can be externally connected to a first signal, thereby outputting the first signal to the first electrode substrate 2 and the third electrode substrate 4 connected to the first connecting part 7; the second connecting part 8 can be externally connected to a second signal, thereby outputting the second signal to the second electrode substrate 3 connected to the second connecting part 8. The first sub-capacitor and the second sub-capacitor are connected in parallel through the first connecting part 7 and the second connecting part 8, thereby forming a capacitor 100, such that the capacitance value of the capacitor 100 is C0 = C1 + C2. When the area of ​​the integrated capacitor in the filter is limited, the above capacitor structure increases the capacitance value of the capacitor 100, achieving the purpose of high capacitance adjustment of the integrated capacitor in the filter, and realizing high-performance capacitance control of the filter. It is understood that the performance of the filter can be improved by connecting the capacitor 100 in series or in parallel with the resonator.

[0046] The filter provided in this embodiment of the utility model has a structure in which a first electrode substrate, a first dielectric layer, a second electrode substrate, a second dielectric layer and a third electrode substrate are stacked sequentially on one side of the substrate. The first electrode substrate and the third electrode substrate are connected by a first connecting part, and the second electrode substrate is reused to form two parallel sub-capacitors. The capacitance of the capacitor is the sum of the capacitances of the parallel sub-capacitors, which increases the bandwidth of the filter. The filter can be adjusted over a wider range of capacitances, and high-performance capacitance control of the filter is achieved.

[0047] Figure 2 This is a schematic diagram of another filter structure provided in an embodiment of the present invention, for reference. Figure 2 Along the thickness direction X of substrate 1, the thickness of the first dielectric layer 5 is d1, and the thickness of the second dielectric layer 6 is d2; where 0.8≤d1 / d2≤1.2.

[0048] Specifically, the thickness ratio d1 / d2 of the first dielectric layer 5 and the second dielectric layer 6 is set between 0.8 and 1.2 along the thickness direction X of the substrate 1, so that the thickness d1 of the first dielectric layer 5 and the thickness d2 of the second dielectric layer 6 are approximately equal or equal, and the thickness difference between the two dielectric layers is relatively small. This makes the electric field distribution in the two dielectric layers more uniform, which helps to improve the stability of the capacitor 100 and avoids that the thickness difference between the first dielectric layer 5 and the second dielectric layer 6 is too large, which would cause the electric field strength to weaken in the thicker dielectric layer and strengthen in the thinner dielectric layer, thereby affecting the performance and reliability of the capacitor.

[0049] In this embodiment of the invention, the thickness ratio of the first dielectric layer and the second dielectric layer is set between 0.8 and 1.2 along the thickness direction of the substrate, so that the thickness of the first dielectric layer and the thickness of the second dielectric layer are approximately equal or equal, thereby improving the stability of the capacitor and thus improving the performance of the filter.

[0050] Optional, continue to refer to Figure 2 Along the thickness direction X of substrate 1, the first electrode substrate 2 and the second electrode substrate 3 have a first overlapping region 11, and the second electrode substrate 3 and the third electrode substrate 4 have a second overlapping region 12; the orthographic projection of the first dielectric layer 5 onto the plane of substrate 1 covers the orthographic projection of the first overlapping region 11 onto the plane of substrate 1; the orthographic projection of the second dielectric layer 6 onto the plane of substrate 1 covers the orthographic projection of the second overlapping region 12 onto the plane of substrate 1.

[0051] Specifically, the orthographic projection of the first dielectric layer 5 onto the plane of the substrate 1 covers the orthographic projection of the first overlapping region 11 onto the plane of the substrate 1. That is, along the extension direction of the substrate 1, the length of the first dielectric layer 5 is greater than the length of the first overlapping region 11 of the first electrode substrate 2 and the second electrode substrate 3. Thus, when the first electrode substrate 2, the first dielectric layer 5, and the second electrode substrate 3 form the first sub-capacitor, the first dielectric layer 5 can provide reliable insulation coverage for the first overlapping region 11. By fully utilizing the first overlapping region 11 of the first electrode substrate 2 and the second electrode substrate 3, the entire first overlapping region 11 becomes the effective working area of ​​the first sub-capacitor. This improves the utilization rate of the first electrode substrate 2 and the second electrode substrate 3 while ensuring electrical isolation between them, thus improving the performance and reliability of the filter and preventing short circuits, leakage, or even short circuits.

[0052] The orthographic projection of the second dielectric layer 6 onto the plane of the substrate 1 covers the orthographic projection of the second overlapping region 12 onto the plane of the substrate 1. That is, along the extension direction of the substrate 1, the length of the second dielectric layer 6 is greater than the length of the second overlapping region 12 of the second electrode substrate 3 and the third electrode substrate 4. Therefore, when the second electrode substrate 3, the second dielectric layer 6, and the third electrode substrate 4 form the second sub-capacitor, the second dielectric layer 6 can provide reliable insulation coverage for the second overlapping region 12. By fully utilizing the second overlapping region 12 of the second electrode substrate 3 and the third electrode substrate 4, the entire second overlapping region 12 becomes the effective working area of ​​the first sub-capacitor. This improves the utilization rate of the second electrode substrate 3 and the third electrode substrate 4 while ensuring electrical isolation between them, thus improving the performance and reliability of the filter and preventing short circuits, leakage, or even short circuits.

[0053] Figure 3 This is a schematic diagram of another filter structure provided in an embodiment of the present invention, for reference. Figure 3 The capacitor 100 also includes a fourth electrode substrate 9 and a third dielectric layer 10; the third dielectric layer 10 is located on the side of the third electrode substrate 4 away from the substrate 1, and the fourth electrode substrate 9 is located on the side of the third dielectric layer 10 away from the substrate 1; the second connecting portion 8 is also connected to the fourth electrode substrate 9.

[0054] Specifically, the third dielectric layer 10 is located on the side of the third electrode substrate 4 away from the substrate 1, and the fourth electrode substrate 9 is located on the side of the third dielectric layer 10 away from the substrate 1. With this arrangement, the third electrode substrate 4, the third dielectric layer 10, and the fourth electrode substrate 9 constitute a third sub-capacitor. The third electrode substrate 4 can be reused as the lower electrode of the third sub-capacitor, and the fourth electrode substrate 9 can be the upper electrode of the third sub-capacitor. The capacitance value of the third sub-capacitor is C3. The first connection portion 7 can be externally connected to a first signal, thereby outputting the first signal to the first electrode substrate 2 and the third electrode substrate 4 connected to the first connection portion 7. The second connection portion 8 can be externally connected to a second signal, thereby outputting the second signal to the second electrode substrate 3 and the fourth electrode substrate 9 connected to the second connection portion 8. The first sub-capacitor, the second sub-capacitor, and the third sub-capacitor are connected in parallel through the first connection portion 7 and the second connection portion 8 to form a capacitor 100, such that the capacitance value of the capacitor 100 is C0 = C1 + C2 + C3. Given the limited area of ​​the integrated capacitor in the filter, the above capacitor structure further increases the capacitance value of capacitor 100, which can achieve the purpose of high capacitance adjustment of the integrated capacitor in the filter and realize the high-performance capacitance control of the filter.

[0055] The filter provided in this embodiment of the utility model has a structure in which a first electrode substrate, a first dielectric layer, a second electrode substrate, a second dielectric layer, a third electrode substrate, a third dielectric layer, and a fourth electrode substrate are stacked sequentially on one side of the substrate. The first electrode substrate and the third electrode substrate are connected by a first connecting part, and the second electrode substrate and the fourth electrode substrate are connected by a second connecting part. The second electrode substrate and the third electrode substrate are reused to form three parallel sub-capacitors, so that the capacitance of the capacitor is the sum of the capacitances of the parallel sub-capacitors, which further increases the bandwidth of the filter. The filter can be adjusted over a wider range of capacitance, and high-performance capacitance control of the filter is achieved.

[0056] Figure 4 This is a schematic diagram of another filter structure provided in an embodiment of the present invention, for reference. Figure 4 Along the thickness direction of the substrate, the thickness of the first dielectric layer is d1, the thickness of the second dielectric layer is d2, and the thickness of the third dielectric layer is d3; where 0.8≤d1 / d2≤1.2 and 0.8≤d2 / d3≤1.2.

[0057] Specifically, along the thickness direction X of the substrate 1, the thickness ratio d1 / d2 of the first dielectric layer 5 and the second dielectric layer 6 is set between 0.8 and 1.2, and the thickness ratio d2 / d3 of the second dielectric layer 6 and the third dielectric layer 10 is also between 0.8 and 1.2. This ensures that the thicknesses d1 of the first dielectric layer 5, d2 of the second dielectric layer 6, and d3 of the third dielectric layer 10 are approximately equal or identical, resulting in relatively small thickness differences among the three dielectric layers. This makes the electric field distribution more uniform across the three dielectric layers, which helps improve the stability of the capacitor 100 and avoids excessive thickness differences among the first dielectric layer 5, the second dielectric layer 6, and the third dielectric layer 10, which would cause the electric field strength to weaken in thicker dielectric layers and strengthen in thinner dielectric layers, thereby affecting the performance and reliability of the capacitor.

[0058] In this embodiment of the invention, the thickness ratio of the first dielectric layer and the second dielectric layer is set between 0.8 and 1.2 along the thickness direction of the substrate, and the value of the thickness ratio d2 / d3 of the second dielectric layer and the third dielectric layer is between 0.8 and 1.2, so that the thicknesses of the first dielectric layer, the second dielectric layer and the third dielectric layer are approximately equal or equal, thereby improving the stability of the capacitor and thus improving the performance of the filter.

[0059] Optional, continue to refer to Figure 4 Along the thickness direction X of substrate 1, the third electrode substrate 4 and the fourth electrode substrate 9 have a third overlapping region 13; the orthographic projection of the third dielectric layer 10 onto the plane of substrate 1 covers the orthographic projection of the third overlapping region 13 onto the plane of substrate 1.

[0060] Specifically, the orthographic projection of the third dielectric layer 10 onto the plane of the substrate 1 covers the orthographic projection of the third overlapping region 13 onto the plane of the substrate 1. That is, along the extension direction of the substrate 1, the length of the third dielectric layer 10 is greater than the length of the third overlapping region 13 of the third electrode substrate 4 and the fourth electrode substrate 9. Therefore, when the third electrode substrate 4, the third dielectric layer 10, and the fourth electrode substrate 9 form the third sub-capacitor, the third dielectric layer 10 can provide reliable insulation coverage for the third overlapping region 13. By fully utilizing the third overlapping region 13 of the third electrode substrate 4 and the fourth electrode substrate 9, the entire third overlapping region 13 becomes the effective working area of ​​the third sub-capacitor. This improves the utilization rate of the third electrode substrate 4 and the fourth electrode substrate 9 while ensuring electrical isolation between them, thus improving the performance and reliability of the filter and preventing short circuits, leakage, or even short circuits.

[0061] Figure 5 This is a schematic diagram of another filter structure provided in an embodiment of the present invention, for reference. Figure 5 Along the thickness direction of substrate 1, the first electrode substrate 2 and the second electrode substrate 3 have a first overlapping region 11, and the second electrode substrate 3 and the third electrode substrate 4 have a second overlapping region 12; the orthographic projection of the first overlapping region 11 onto the plane of substrate 1 covers the orthographic projection of the first dielectric layer 5 onto the plane of substrate 1; the orthographic projection of the second overlapping region 12 onto the plane of substrate 1 covers the orthographic projection of the second dielectric layer 6 onto the plane of substrate 1.

[0062] Specifically, the orthographic projection of the first overlapping region 11 onto the plane of the substrate 1 covers the orthographic projection of the first dielectric layer 5 onto the plane of the substrate 1. That is, along the extension direction of the substrate 1, the length of the first overlapping region 11 of the first electrode substrate 2 and the second electrode substrate 3 is greater than the length of the first dielectric layer 5. Therefore, when the first electrode substrate 2, the first dielectric layer 5, and the second electrode substrate 3 form the first sub-capacitor, the first overlapping region 11 can cover the first dielectric layer 5. By fully utilizing the first dielectric layer 5, the entire area of ​​the first dielectric layer 5 becomes the effective working area of ​​the first sub-capacitor, improving the utilization rate of the first dielectric layer 5. The electric field between the first electrode substrate 2 and the second electrode substrate 3 can pass through the first dielectric layer 5 more effectively, thereby increasing the capacitance value.

[0063] The orthographic projection of the second overlapping region 12 onto the plane of the substrate 1 covers the orthographic projection of the second dielectric layer 6 onto the plane of the substrate 1. That is, along the extension direction of the substrate 1, the length of the second overlapping region 12 of the second electrode substrate 3 and the third electrode substrate 4 is greater than the length of the second dielectric layer 6. Therefore, when the second electrode substrate 3, the second dielectric layer 6, and the third electrode substrate 4 form the second sub-capacitor, the second overlapping region 12 can cover the second dielectric layer 6. By fully utilizing the second dielectric layer 6, the entire area of ​​the second dielectric layer 6 becomes the effective working area of ​​the second sub-capacitor, improving the utilization rate of the second dielectric layer 6. The electric field between the second electrode substrate 3 and the third electrode substrate 4 can pass through the second dielectric layer 6 more effectively, thereby increasing the capacitance value.

[0064] This embodiment of the invention improves the utilization rate of the first and second dielectric layers by setting the orthogonal projection of the first overlapping region onto the plane of the substrate to cover the orthogonal projection of the first dielectric layer onto the plane of the substrate; and the orthogonal projection of the second overlapping region onto the plane of the substrate to cover the orthogonal projection of the second dielectric layer onto the plane of the substrate. This increases the capacitance value while maximizing the use of the first and second dielectric layers to achieve capacitive coupling, reducing the loss of electric field in the non-coupling region, and allowing more electric field energy to be concentrated in the coupling region. This improves the electromagnetic coupling efficiency between the first and second electrode substrates and between the second and third electrode substrates, thus helping to improve the performance of the filter.

[0065] Figure 6 This is a schematic diagram of another filter structure provided in an embodiment of the present invention, for reference. Figure 6 Along the thickness direction X of the substrate 1, the third electrode substrate 4 and the fourth electrode substrate 9 have a third overlapping region 13; the orthographic projection of the third overlapping region 13 onto the plane of the substrate 1 covers the orthographic projection of the third dielectric layer 10 onto the plane of the substrate.

[0066] Specifically, the orthographic projection of the third overlapping region 13 onto the plane of the substrate 1 covers the orthographic projection of the third dielectric layer 10 onto the plane of the substrate 1. That is, along the extension direction of the substrate 1, the length of the third overlapping region 13 of the third electrode substrate 4 and the fourth electrode substrate 9 is greater than the length of the third dielectric layer 10. Therefore, when the third electrode substrate 4, the third dielectric layer 10, and the fourth electrode substrate 9 form the third sub-capacitor, the third overlapping region 13 can cover the third dielectric layer 10. By fully utilizing the third dielectric layer 10, the entire area of ​​the third dielectric layer 10 becomes the effective working area of ​​the third sub-capacitor, improving the utilization rate of the third dielectric layer 10. The electric field between the third electrode substrate 4 and the fourth electrode substrate 9 can pass through the third dielectric layer 10 more effectively, thereby increasing the capacitance value.

[0067] This embodiment of the invention improves the utilization rate of the third dielectric layer by setting the orthogonal projection of the third overlapping region on the plane of the substrate to cover the orthogonal projection of the third dielectric layer on the plane of the substrate. While increasing the capacitance value, it maximizes the use of the third dielectric layer to achieve capacitive coupling, reduces the loss of electric field in the non-coupling region, and allows more electric field energy to be concentrated in the coupling region. This improves the electromagnetic coupling efficiency between the third electrode substrate and the fourth electrode substrate, which helps to improve the performance of the filter.

[0068] Figure 7 This is a schematic diagram of another filter structure provided in an embodiment of the present invention, for reference. Figure 7 The filter also includes a resonator 200;

[0069] The resonator 200 includes a fifth electrode substrate 14, a piezoelectric layer 15, and a sixth electrode substrate 16; the sixth electrode substrate 16 is connected to the first connection portion 7.

[0070] The piezoelectric layer 15 is located on the side of the fifth electrode substrate 14 away from the substrate 1, and the sixth electrode substrate 16 is located on the side of the piezoelectric layer 15 away from the substrate 1.

[0071] A groove 17 is provided in the surface of the substrate 1 near the resonator 200, and the resonator 200 and the groove 17 overlap at least partially along the thickness direction X of the substrate 1.

[0072] Specifically, the resonator 200 consists of a fifth electrode substrate 14, a piezoelectric layer 15 located on the side of the fifth electrode substrate 14 away from the substrate 1, and a sixth electrode substrate 16 located on the side of the piezoelectric layer 15 away from the substrate 1. The combination of the fifth electrode substrate 14, the piezoelectric layer 15, and the sixth electrode substrate 16 can generate resonance at a specific frequency, allowing the filter to accurately filter signals in a certain frequency band. The sixth electrode substrate 16 is connected to the first connection part 7, thus connecting the capacitor 100 to the resonator 200. By controlling the capacitance value of the capacitor 100, the resonant frequency of the resonator 200 can be precisely adjusted. Furthermore, the capacitor 100 can increase the bandwidth of the resonator 200, thereby expanding the frequency band of the resonator 200 and broadening the application range of the filter. A groove 17 is provided in the surface of the substrate 1 on the side close to the resonator 200, and the resonator 200 and the groove 17 overlap at least partially. The groove 17 can serve as a shielding structure to reduce the interference of external electromagnetic signals to the resonator 200. When external electromagnetic waves irradiate the substrate 1, the groove 17 can reflect or scatter part of the electromagnetic waves, causing them to move away from the resonator 200, thereby reducing the impact of interference signals on the resonator and improving the anti-interference capability of the filter.

[0073] This embodiment of the invention uses a combination of a fifth electrode substrate, a piezoelectric layer, and a sixth electrode substrate to filter signals of a specific frequency. The sixth electrode substrate is connected to the first connection portion, enabling the connection between the capacitor and the resonator. This allows for precise adjustment of the resonant frequency while increasing the bandwidth of the resonator, thus broadening the application range of the filter. A groove is formed in the surface of the substrate near the resonator, with the resonator at least partially overlapping the groove, to shield interference signals and improve the filter's anti-interference capability.

[0074] Optional, continue to refer to Figure 7 The fifth electrode substrate 14 is disposed on the same layer as the second electrode substrate 3; the sixth electrode substrate 16 is disposed on the same layer as the third electrode substrate 4.

[0075] Specifically, the fifth electrode substrate 14 and the second electrode substrate 3 can be made of the same material, and the fifth electrode substrate 14 and the second electrode substrate 3 are disposed in the same layer, so that they can be fabricated in the same manufacturing process; the sixth electrode substrate 16 and the third electrode substrate 4 can be made of the same material, and the sixth electrode substrate 16 and the third electrode substrate 4 are disposed in the same layer, so that they can be fabricated in the same manufacturing process, reducing the complexity and cost of the filter fabrication process.

[0076] The specific embodiments described above do not constitute a limitation on the scope of protection of this utility model. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A filter, characterized by, The filter comprises: a substrate and a capacitor located on one side of the substrate; the capacitor comprises a first electrode substrate, a second electrode substrate, a third electrode substrate, a first dielectric layer, a second dielectric layer, a first connecting part and a second connecting part; the first dielectric layer is located on the side of the first electrode substrate away from the substrate, the second electrode substrate is located on the side of the first dielectric layer away from the substrate, the second dielectric layer is located on the side of the second electrode substrate away from the substrate, and the third electrode substrate is located on the side of the second dielectric layer away from the substrate; the first connecting part is connected with the first electrode substrate and the third electrode substrate respectively, and the second connecting part is connected with the second electrode substrate.

2. The filter of claim 1, wherein, The capacitor further comprises a fourth electrode substrate and a third dielectric layer; the third dielectric layer is located on the side of the third electrode substrate away from the substrate, and the fourth electrode substrate is located on the side of the third dielectric layer away from the substrate; the second connecting part is further connected with the fourth electrode substrate.

3. The filter of claim 1, wherein, In the thickness direction of the substrate, the thickness of the first dielectric layer is d1, and the thickness of the second dielectric layer is d2; wherein 0.8≤d1 / d2≤1.

2.

4. The filter of claim 2, wherein, In the thickness direction of the substrate, the thickness of the first dielectric layer is d1, the thickness of the second dielectric layer is d2, and the thickness of the third dielectric layer is d3; wherein 0.8≤d1 / d2≤1.2, 0.8≤d2 / d3≤1.

2.

5. The filter of claim 1, wherein, In the thickness direction of the substrate, the first electrode substrate and the second electrode substrate have a first overlapping area, and the second electrode substrate and the third electrode substrate have a second overlapping area; the first dielectric layer covers the first overlapping area in the orthographic projection of the substrate plane; the second dielectric layer covers the second overlapping area in the orthographic projection of the substrate plane.

6. The filter of claim 1, wherein, In the thickness direction of the substrate, the first electrode substrate and the second electrode substrate have a first overlapping area, and the second electrode substrate and the third electrode substrate have a second overlapping area; the first overlapping area covers the first dielectric layer in the orthographic projection of the substrate plane; the second overlapping area covers the second dielectric layer in the orthographic projection of the substrate plane.

7. The filter of claim 2, wherein, In the thickness direction of the substrate, the third electrode substrate and the fourth electrode substrate have a third overlapping area; the third dielectric layer covers the third overlapping area in the orthographic projection of the substrate plane.

8. The filter of claim 2, wherein, In the thickness direction of the substrate, the third electrode substrate and the fourth electrode substrate have a third overlapping area; the third overlapping area covers the third dielectric layer in the orthographic projection of the substrate plane.

9. The filter of claim 1, wherein, The filter further comprises a resonator; the resonator comprises a fifth electrode substrate, a piezoelectric layer and a sixth electrode substrate; the sixth electrode substrate is connected with the first connecting part; The piezoelectric layer is located on the side of the fifth electrode substrate away from the substrate, and the sixth electrode substrate is located on the side of the piezoelectric layer away from the substrate; The surface of the substrate near the resonator side is provided with a groove, and the resonator and the groove at least partially overlap in the thickness direction of the substrate.

10. The filter of claim 9, wherein, The fifth electrode substrate is provided in the same layer as the second electrode substrate; The sixth electrode substrate is provided in the same layer as the third electrode substrate.

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