Hybrid filter and radio frequency front-end module

Abstract

The invention discloses a hybrid filter and a radio frequency front-end module, and relates to the field of filtering, and the hybrid filter comprises a substrate, and a first electrode layer is formed on the first side surface of the substrate; the acoustic wave filter is located on the first side of the substrate and comprises at least one acoustic wave resonator, and each acoustic wave resonator comprises a first electrode located on the surface of the first side of the substrate and a second electrode located on the surface of the second side of the substrate; the second electrode is located on the side, away from the substrate, of the first electrode; the piezoelectric layer is located between the first electrode and the second electrode; the air cavity is located on the side, away from the second electrode, of the first electrode; the electromagnetic filter is located on the first side surface of the substrate, the electromagnetic filter comprises at least one electromagnetic resonator, the electromagnetic resonator comprises a third electrode located on the first side surface of the substrate, and the third electrode and the first electrode belong to constituent parts of the first electrode layer. The hybrid filter comprises both an acoustic wave filter and an electromagnetic filter.

Description

Technical Field

[0001] This application relates to the field of filtering technology, and in particular to a hybrid filter and an RF front-end module including the hybrid filter. Background Technology

[0002] Filters are key frequency-selective devices in wireless communication systems. Their function is to select the frequency of signals, allowing signals within a specific frequency band to pass while suppressing out-of-band interference and noise, thereby ensuring the signal integrity and signal-to-noise ratio of the communication link. Currently, the mainstream filter implementation technologies in RF front-end design mainly include acoustic filters and electromagnetic filters. Among them, acoustic filters utilize the acoustic resonance characteristics of piezoelectric materials to achieve high Q values ​​and small size filtering functions, making them particularly suitable for mobile terminals with stringent requirements for size and out-of-band suppression. Electromagnetic filters, on the other hand, are based on the resonance and coupling principles of electromagnetic fields, exhibiting excellent power capacity and thermal stability in high-frequency and high-power applications.

[0003] In modern wireless communication systems, especially in 4G / 5G mobile terminals and access devices that support multi-band and multi-mode operation, acoustic filters and electromagnetic filters are typically integrated into the RF front-end module in discrete or modular form. As communication technologies evolve towards higher standards such as 5G-Advanced and WiFi-6, simultaneously incorporating acoustic and electromagnetic filters into the RF front-end module has become a key technology for achieving high-performance RF front-ends. Therefore, providing a hybrid filter that simultaneously includes both acoustic and electromagnetic filters has become a research direction for those skilled in the art. Summary of the Invention

[0004] In view of the above problems, this application provides a hybrid filter and an RF front-end module to achieve the purpose of a hybrid filter that simultaneously includes an acoustic filter and an electromagnetic filter. The specific solution is as follows:

[0005] A hybrid filter, comprising:

[0006] A substrate, wherein a first electrode layer is formed on a first side surface of the substrate;

[0007] An acoustic wave filter located on a first side of the substrate, the acoustic wave filter including at least one acoustic wave resonator, the acoustic wave resonator including: a first electrode located on the first side surface of the substrate, a second electrode located on the side of the first electrode away from the substrate, a piezoelectric layer located between the first electrode and the second electrode, and an air cavity located on the side of the first electrode away from the second electrode;

[0008] An electromagnetic filter located on a first side surface of the substrate, the electromagnetic filter including at least one electromagnetic resonator, the electromagnetic resonator including a third electrode located on the first side surface of the substrate, the third electrode and the first electrode being part of the first electrode layer.

[0009] Optionally, the third electrode and the first electrode of the first acoustic resonator in the at least one acoustic resonator are electrically connected through an interconnection structure.

[0010] Alternatively, the third electrode and the first electrode of the first acoustic resonator in the at least one acoustic resonator may be different components of the same electrode block.

[0011] Optionally, the electromagnetic filter is a microstrip line filter.

[0012] Optionally, the microstrip line filter includes a first microstrip line resonator, and the third electrode is the first microstrip line resonator.

[0013] Optionally, the third electrode includes a first end and a second end opposite to each other, the first end of the third electrode is grounded and the second end is floating, and the length of the third electrode is related to one-quarter of the wavelength corresponding to the resonant frequency of the first microstrip line resonator.

[0014] Optionally, the third electrode includes a first end and a second end opposite to each other, the first end of the third electrode is floating, the second end is floating, and the length of the third electrode is related to half the wavelength corresponding to the resonant frequency of the first microstrip line resonator.

[0015] Optionally, the microstrip line filter further includes a second microstrip line resonator and a third microstrip line resonator, and the first electrode layer further includes a fourth electrode and a fifth electrode, wherein the second microstrip line resonator is the fourth electrode and the third microstrip line resonator is the fifth electrode;

[0016] The fourth electrode extends along a first direction and has an insulating gap between it and the third electrode in a second direction. The third electrode extends in the first direction. The first direction and the second direction are parallel to the plane of the substrate, and the first direction and the second direction are different.

[0017] In the second direction, the third microstrip line resonator is located on the side of the second microstrip line resonator away from the first microstrip line resonator, and the fifth electrode extends along the first direction and has an insulating gap between it and the fourth electrode in the second direction.

[0018] Optionally, the acoustic filter includes at least two acoustic resonators, which are connected in parallel or in series.

[0019] Alternatively, the acoustic filter may include at least three acoustic resonators, some of which are connected in parallel and some in series.

[0020] Optionally, the electromagnetic filter is a stripline filter, the stripline filter includes a first stripline resonator, and the third electrode is a component of the first stripline resonator;

[0021] Alternatively, the electromagnetic filter is a substrate integrated waveguide filter, which includes a first substrate integrated waveguide resonator, and the third electrode is a component of the first substrate integrated waveguide resonator.

[0022] Optionally, a second electrode layer is formed on the second side surface of the substrate, and the second side of the substrate is opposite to the first side of the substrate; the substrate has a conductive via penetrating the substrate;

[0023] The second electrode layer includes a first lead-out terminal and a second lead-out terminal. The first lead-out terminal is the input terminal of the hybrid filter and is electrically connected to the input terminal of the electromagnetic filter through the conductive via. The second lead-out terminal is the output terminal of the hybrid filter and is electrically connected to the output terminal of the acoustic filter through the conductive via.

[0024] Optionally, the second electrode layer may further include a ground electrode layer for providing a ground signal.

[0025] Optionally, the substrate is a silicon substrate.

[0026] A radio frequency front-end module, comprising: the hybrid filter described in any one of the preceding claims.

[0027] The hybrid filter provided in this application includes both an acoustic filter and an electromagnetic filter. Furthermore, in the hybrid filter provided in this application, both the electromagnetic filter and the acoustic filter are fabricated on one side surface of the substrate, and the first electrode used to fabricate the acoustic filter and the third electrode used to fabricate the electromagnetic filter are components of the same electrode layer (the first electrode layer). This improves the consistency of the manufacturing process of the hybrid filter, reduces the cost of the hybrid filter, and is more conducive to the mass production of the hybrid filter. Attached Figure Description

[0028] The above and other features, advantages, and aspects of the embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description. Throughout the drawings, the same or similar reference numerals denote the same or similar elements. It should be understood that the drawings are schematic, and the originals and elements are not necessarily drawn to scale.

[0029] Figure 1 A schematic diagram of the structure of a hybrid filter provided in this application;

[0030] Figure 2 A top view of a hybrid filter provided in this application;

[0031] Figure 3 A schematic diagram of another hybrid filter provided in this application;

[0032] Figure 4 A schematic diagram of another hybrid filter provided in this application;

[0033] Figure 5 A schematic diagram of another hybrid filter provided in this application;

[0034] Figure 6 A schematic diagram of another hybrid filter provided in this application;

[0035] Figure 7 This is a schematic diagram of another hybrid filter provided in this application. Detailed Implementation

[0036] The embodiments of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0037] Various modifications and variations can be made to this application without departing from its spirit or scope, which will be apparent to those skilled in the art. Therefore, this application is intended to cover modifications and variations falling within the scope of the corresponding claims (the claimed technical solutions) and their equivalents. It should be noted that the implementation methods provided in the embodiments of this application can be combined with each other without contradiction.

[0038] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, this application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] As described in the background section, providing a hybrid filter that simultaneously includes an acoustic filter and an electromagnetic filter has become a research direction for those skilled in the art.

[0040] In view of this, embodiments of this application provide a hybrid filter, such as... Figure 1 and Figure 2 As shown, the hybrid filter includes:

[0041] Substrate 10, wherein a first electrode layer is formed on a first side surface of the substrate 10;

[0042] An acoustic wave filter 20 is located on a first side of the substrate 10. The acoustic wave filter 20 includes at least one acoustic wave resonator, which includes: a first electrode 21 located on the first side surface of the substrate 10; a second electrode 22 located on the side of the first electrode 21 away from the substrate 10; a piezoelectric layer 23 located between the first electrode 21 and the second electrode 22; and an air cavity 24 located on the side of the first electrode 21 away from the second electrode 22. It should be noted that, in this embodiment, the first side of the substrate 10 has a groove, and the first electrode layer covers the groove to form the air cavity 24.

[0043] An electromagnetic filter 30 is located on a first side surface of the substrate 10. The electromagnetic filter 30 includes at least one electromagnetic resonator. The electromagnetic resonator includes a third electrode 31 located on the first side surface of the substrate 10. The third electrode 31 and the first electrode 21 are components of the first electrode layer.

[0044] The hybrid filter provided in this application embodiment includes both an acoustic filter 20 and an electromagnetic filter 30. Furthermore, in the hybrid filter provided in this application embodiment, both the electromagnetic filter 30 and the acoustic filter 20 are fabricated on one side surface of the substrate 10, and the first electrode 21 used to fabricate the acoustic filter and the third electrode 31 used to fabricate the electromagnetic filter 30 are components of the same electrode layer (first electrode layer). This improves the consistency of the manufacturing process of the hybrid filter, reduces the cost of the hybrid filter, and is more conducive to the mass production of the hybrid filter.

[0045] Optionally, in one embodiment of this application, the third electrode 31 and the first electrode 21 of the first acoustic resonator in the at least one acoustic resonator are directly electrically connected via an interconnection structure 40. Specifically, in this embodiment, if the acoustic filter 20 includes one acoustic resonator, the third electrode 31 is electrically connected to the first electrode 21 of that acoustic resonator via the interconnection structure 40; if the acoustic filter 20 includes at least two acoustic resonators, the third electrode 31 is directly electrically connected to the first electrode 21 of one acoustic resonator in the acoustic filter 20 via the interconnection structure 40, and the first electrodes 21 of other acoustic resonators may or may not be directly electrically connected. The acoustic resonator including the first electrode 21 electrically connected to the third electrode 31 is referred to as the first acoustic resonator. For example, continuing as follows... Figure 2As shown, the acoustic filter includes two acoustic resonators: a first acoustic resonator and a second acoustic resonator. The first electrode 21 of the first acoustic resonator is directly electrically connected to the third electrode 31 through the interconnection structure 40. The second electrode 22 of the second acoustic resonator is electrically connected to the first electrode 21 of the first acoustic resonator or is the same electrode.

[0046] In another embodiment of this application, the third electrode 31 and the first electrode 21 of the first acoustic resonator in the at least one acoustic resonator are different components of the same electrode, that is, a portion of the same electrode block is used as the first electrode 21 of the acoustic resonator, and a portion is used as the third electrode 31 of the electromagnetic resonator. This application does not limit this, and it depends on the specific circumstances.

[0047] Based on any of the above embodiments, in one embodiment of this application, the electromagnetic filter is a microstrip line filter, and in this embodiment, the electromagnetic resonator is a microstrip line resonator. It should be noted that a microstrip line resonator is a resonant structure constructed using a microstrip transmission line with an open / short-circuited start or end. When an electromagnetic wave propagates in the microstrip line and is reflected at both ends (or at points of structural discontinuity), a standing wave is formed at a frequency that satisfies a specific phase condition, thereby causing resonance at that frequency.

[0048] Specifically, in one embodiment of this application, the microstrip line filter includes a first microstrip line resonator. In this embodiment, the third electrode 31 is the first microstrip line resonator, and the resonant frequency of the first microstrip line resonator is related to the length of the third electrode 31 along its extension direction.

[0049] Optionally, in one embodiment of this application, the third electrode 31 includes a first end and a second end opposite to each other. The first end of the third electrode 31 is grounded and the second end is floating. That is, one end of the third electrode 31 is grounded and the other end is floating. In this embodiment, the length of the third electrode 31 is related to one-quarter of the wavelength corresponding to the resonant frequency of the first microstrip line resonator. For example, the length of the third electrode 31 is one-quarter of the wavelength corresponding to the resonant frequency of the first microstrip line resonator.

[0050] In another embodiment of this application, the third electrode 31 includes a first end and a second end opposite to each other. The first end of the third electrode 31 is floating, and the second end is also floating, that is, both ends of the third electrode 31 are floating. In this embodiment, the length of the third electrode 31 is related to half of the wavelength corresponding to the resonant frequency of the first microstrip line resonator. For example, the length of the third electrode 31 is half of the wavelength corresponding to the resonant frequency of the first microstrip line resonator.

[0051] Based on any of the above embodiments, in one embodiment of this application, the microstrip line filter includes two microstrip line resonators. In this embodiment, the microstrip line filter further includes a second microstrip line resonator, and the first electrode layer further includes a fourth electrode 32, wherein the second microstrip line resonator is the fourth electrode 32. In this embodiment, the fourth electrode 32 extends along a first direction and has an insulating gap with the third electrode 31 in a second direction. It should be noted that in this embodiment, the extending direction of the third electrode 31 is also the first direction. Both the first direction and the second direction are parallel to the plane where the substrate 10 is located, and the first direction and the second direction are different.

[0052] In another embodiment of this application, the microstrip line filter includes three microstrip line resonators. In this embodiment, the microstrip line filter further includes a second microstrip line resonator and a third microstrip line resonator. The first electrode layer further includes a fourth electrode 32 and a fifth electrode 33, wherein the second microstrip line resonator is the fourth electrode 32, and the third microstrip line resonator is the fifth electrode 33. Specifically, in this embodiment, the fourth electrode 32 extends along a first direction and has an insulating gap between it and the third electrode 31 in a second direction. The extension direction of the third electrode 31 is the first direction. The first direction and the second direction are parallel to the plane where the substrate 10 is located, and the first direction and the second direction are different.

[0053] In the second direction, the third microstrip line resonator is located on the side of the second microstrip line resonator away from the first microstrip line resonator, and the fifth electrode 33 extends along the first direction and has an insulating gap between it and the fourth electrode 32 in the second direction.

[0054] It should be noted that, in various embodiments of this application, the resonant frequency of the second microstrip line resonator is related to the length of the fourth electrode 32 along its extension direction.

[0055] Optionally, in one embodiment of this application, the fourth electrode 32 includes a first end and a second end opposite to each other. The first end of the fourth electrode 32 is grounded and the second end is floating. That is, one end of the fourth electrode 32 is grounded and the other end is floating. In this embodiment, the length of the fourth electrode 32 is related to one-quarter of the wavelength corresponding to the resonant frequency of the second microstrip line resonator. For example, the length of the fourth electrode 32 is one-quarter of the wavelength corresponding to the resonant frequency of the second microstrip line resonator.

[0056] In another embodiment of this application, the fourth electrode 32 includes a first end and a second end opposite to each other. The first end of the fourth electrode 32 is floating, and the second end is also floating, that is, both ends of the fourth electrode 32 are floating. In this embodiment, the length of the fourth electrode 32 is related to half of the wavelength corresponding to the resonant frequency of the second microstrip line resonator. For example, the length of the fourth electrode 32 is half of the wavelength corresponding to the resonant frequency of the second microstrip line resonator.

[0057] It should be noted that, in the various embodiments of this application, the resonant frequency of the third microstrip line resonator and the length of the fifth electrode 33 along its extension direction are related.

[0058] Optionally, in one embodiment of this application, the fifth electrode 33 includes a first end and a second end opposite to each other. The first end of the fifth electrode 33 is grounded and the second end is floating. That is, one end of the fifth electrode 33 is grounded and the other end is floating. In this embodiment, the length of the fifth electrode 33 is related to one-quarter of the wavelength corresponding to the resonant frequency of the third microstrip line resonator. For example, the length of the fifth electrode 33 is one-quarter of the wavelength corresponding to the resonant frequency of the third microstrip line resonator.

[0059] In another embodiment of this application, the fifth electrode 33 includes a first end and a second end opposite to each other. The first end of the fifth electrode 33 is floating, and the second end is also floating, that is, both ends of the fifth electrode 33 are floating. In this embodiment, the length of the fifth electrode 33 is related to half of the wavelength corresponding to the resonant frequency of the third microstrip line resonator. For example, the length of the fifth electrode 33 is half of the wavelength corresponding to the resonant frequency of the third microstrip line resonator.

[0060] Although the above embodiments are described with the example of the microstrip line filter including at most three microstrip line resonators, this application does not limit this. In other embodiments of this application, the microstrip line filter may also include other numbers of microstrip line resonators. For example, the microstrip line filter includes N microstrip line resonators, where N can be any integer greater than 2.

[0061] Optionally, in this embodiment, regardless of how many microstrip line resonators the microstrip line filter includes, each microstrip line resonator is composed of a microstrip transmission line with an open or short-circuited start and end. This microstrip transmission line is located on the same layer as the third electrode 31, that is, it is also a component of the first electrode layer, thereby further improving the process consistency of the hybrid filter and reducing the cost of the hybrid filter.

[0062] Moreover, with the development of acoustic filters, the application frequency of acoustic filters is gradually increasing and is no longer limited to the low-frequency range. Microstrip line filters have a higher Q value and can be used in a higher frequency range, which makes the hybrid filter provided in this application embodiment very advantageous in the high-frequency field.

[0063] It should be noted that the above embodiments are described with the example that each electromagnetic resonator in the electromagnetic filter is a microstrip line resonator. In other embodiments of this application, the electromagnetic filter may also include electromagnetic resonators with other structures.

[0064] Optionally, in one embodiment of this application, the electromagnetic filter is a stripline filter, and in this embodiment, each electromagnetic resonator in the electromagnetic filter is a stripline resonator. In this embodiment, the stripline filter includes a first stripline resonator, and the third electrode 31 is a component of the first stripline resonator. Optionally, the third electrode 31 can be a conductor strip of the first stripline resonator or a ground plane of the first stripline resonator; this application does not limit this, and it depends on the specific circumstances.

[0065] In another embodiment of this application, the electromagnetic filter is a substrate integrated waveguide (SIW) filter, and the electromagnetic resonator in the electromagnetic filter is a substrate integrated waveguide resonator. In this embodiment, the substrate integrated waveguide filter includes a first substrate integrated waveguide resonator, and the third electrode 31 is a component of the first substrate integrated waveguide resonator. Optionally, the third electrode 31 is a ground plane of the first substrate integrated waveguide resonator.

[0066] In other embodiments of this application, the electromagnetic filter may also include at least two of the following: a partial microstrip line resonator, a stripline resonator, and a substrate integrated waveguide resonator, or may also include other types of electromagnetic resonators. This application does not limit the scope of the electromagnetic filter; the specific type may vary depending on the circumstances.

[0067] Based on any of the above embodiments, in one embodiment of this application, the acoustic resonator in the acoustic filter 20 can be a surface acoustic wave resonator, a bulk acoustic wave resonator, or a thin-film bulk acoustic wave resonator, etc. This application does not limit it in this regard, and it depends on the specific situation.

[0068] Optionally, in one embodiment of this application, the acoustic resonator 201 may be located in the series branch of the hybrid filter, such as... Figure 3 As shown, it can also be located in the parallel branch of the hybrid filter. If the acoustic filter includes at least two acoustic resonators, such as... Figure 4As shown, some acoustic resonators 201 can be located in the parallel branch of the hybrid filter, and some acoustic resonators 201 can be located in the series branch of the hybrid filter. It should be noted that, in the embodiments of this application, the series branch refers to the main road between the input terminal Vin and the output terminal Vout of the hybrid filter; the parallel branch refers to a branch whose one end is electrically connected to the main road between the input terminal Vin and the output terminal Vout of the hybrid filter, and whose other end is grounded.

[0069] Optionally, in one embodiment of this application, such as Figure 5 As shown, the acoustic filter 20 includes at least two acoustic resonators 201, which can be connected in parallel within the acoustic filter 20. Taking the acoustic filter 20 as including a first acoustic resonator and a second acoustic resonator as an example, in one embodiment of this application, the first electrode 21 of the first acoustic resonator is electrically connected to the first electrode 21 of the second acoustic resonator, and the second electrode 22 of the first acoustic resonator is electrically connected to the second electrode 22 of the second acoustic resonator.

[0070] It should be noted that the embodiments of this application are only described with the example of the acoustic filter 20 including the first acoustic resonator and the second acoustic resonator. However, this application does not limit this. In other embodiments of this application, the acoustic filter 20 may also include M acoustic resonators, where M can be any integer greater than 2, depending on the specific situation.

[0071] In another embodiment of this application, such as Figure 6 As shown, the acoustic filter 20 includes at least two acoustic resonators 201, which are connected in series within the acoustic filter 20. Taking the acoustic filter 20 as including a first acoustic resonator and a second acoustic resonator as an example, in one embodiment of this application, the first electrode 21 of the first acoustic resonator is electrically connected to the third electrode 31, and the first electrode 21 of the second acoustic resonator is electrically connected to the second electrode 22 of the first acoustic resonator. The first electrode 21 of the first acoustic resonator is the input port of the acoustic filter 20, and the second electrode 22 of the second acoustic resonator is the output port of the acoustic filter 20, thereby realizing the series connection of the first acoustic resonator and the second acoustic resonator.

[0072] It should be noted that the embodiments of this application are only described with the example of the acoustic filter 20 including the first acoustic resonator and the second acoustic resonator. However, this application does not limit this. In other embodiments of this application, the acoustic filter 20 may also include M acoustic resonators, where M can be any integer greater than 2, depending on the specific situation.

[0073] In yet another embodiment of this application, as Figure 7 As shown, the acoustic filter 20 includes at least three acoustic resonators 201. Inside the acoustic filter 20, some of the at least three acoustic resonators 201 are connected in parallel, and some are connected in series. This application does not limit this, and it depends on the specific situation.

[0074] Based on any of the above embodiments, in one embodiment of this application, a second electrode layer is formed on the second side surface of the substrate 10, and the second side of the substrate 10 is opposite to the first side of the substrate 10; in this embodiment, the substrate 10 also has a conductive via penetrating the substrate 10. Specifically, the second electrode layer includes a first lead-out terminal 51 and a second lead-out terminal 52, wherein the first lead-out terminal 51 is the input terminal of the hybrid filter and is electrically connected to the input terminal of the electromagnetic filter through the conductive via, and the second lead-out terminal 52 is the output terminal of the hybrid filter and is electrically connected to the output terminal of the acoustic filter 20 through the conductive via.

[0075] Based on the above embodiments, in one embodiment of this application, the second electrode layer further includes a ground electrode layer 60 for providing a ground signal. In this embodiment, if the electromagnetic resonator in the electromagnetic filter needs to be grounded, it is electrically connected to the ground electrode layer 60 located on the second side surface of the substrate 10 through a conductive via.

[0076] Optionally, in one embodiment of this application, the first electrode layer and the second electrode layer are metal layers, but this application does not limit this and it depends on the specific circumstances.

[0077] Based on any of the above embodiments, in one embodiment of this application, the substrate 10 may be a silicon substrate or a substrate of other materials. This application does not limit this and it depends on the specific circumstances.

[0078] Based on any of the above embodiments, in one embodiment of this application, the hybrid filter further includes an encapsulation structure 70 that encapsulates the electromagnetic filter and the acoustic filter 20. Optionally, the projection of the encapsulation structure 70 onto the plane where the substrate 10 is located coincides with the substrate 10, but this application does not limit this and it depends on the specific circumstances.

[0079] Accordingly, this application also provides a radio frequency front-end module, which includes the hybrid filter provided in any of the above embodiments. Since the details of the hybrid filter have been described in the above embodiments, this application will not repeat them further.

[0080] In summary, the hybrid filter and RF front-end module including the hybrid filter provided in this application embodiment include both acoustic and electromagnetic filters. Furthermore, in the hybrid filter and RF front-end module including the hybrid filter provided in this application embodiment, both the electromagnetic filter and the acoustic filter are fabricated on one side surface of the substrate, and the first electrode for fabricating the acoustic filter and the third electrode 31 for fabricating the electromagnetic filter are components of the same electrode layer (first electrode layer). This improves the process consistency during the fabrication of the hybrid filter, reduces the cost of the hybrid filter, and is more conducive to the mass production of the hybrid filter.

[0081] The various embodiments in this specification are described in a progressive, parallel, or combined manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other.

[0082] It should be noted that, in the description of this application, the accompanying drawings and embodiments are illustrative rather than restrictive. The same reference numerals throughout the embodiments identify the same structures. It should also be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in an article or device comprising the aforementioned element.

[0083] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A hybrid filter, characterized in that, include: A substrate, wherein a first electrode layer is formed on a first side surface of the substrate; An acoustic wave filter located on a first side of the substrate, the acoustic wave filter including at least one acoustic wave resonator, the acoustic wave resonator including: a first electrode located on the first side surface of the substrate, a second electrode located on the side of the first electrode away from the substrate, a piezoelectric layer located between the first electrode and the second electrode, and an air cavity located on the side of the first electrode away from the second electrode; An electromagnetic filter located on a first side surface of the substrate, the electromagnetic filter including at least one electromagnetic resonator, the electromagnetic resonator including a third electrode located on the first side surface of the substrate, the third electrode and the first electrode being part of the first electrode layer.

2. The hybrid filter according to claim 1, characterized in that, The third electrode and the first electrode of the first acoustic resonator in the at least one acoustic resonator are electrically connected through an interconnection structure. Alternatively, the third electrode and the first electrode of the first acoustic resonator in the at least one acoustic resonator may be different components of the same electrode block.

3. The hybrid filter according to claim 1, characterized in that, The electromagnetic filter is a microstrip line filter.

4. The hybrid filter according to claim 3, characterized in that, The microstrip line filter includes a first microstrip line resonator, and the third electrode is the first microstrip line resonator.

5. The hybrid filter according to claim 4, characterized in that, The third electrode includes a first end and a second end opposite to each other. The first end of the third electrode is grounded and the second end is floating. The length of the third electrode is related to one-quarter of the wavelength corresponding to the resonant frequency of the first microstrip line resonator.

6. The hybrid filter according to claim 4, characterized in that, The third electrode includes a first end and a second end, with the first end of the third electrode floating and the second end floating. The length of the third electrode is related to half the wavelength corresponding to the resonant frequency of the first microstrip line resonator.

7. The hybrid filter according to claim 4, characterized in that, The microstrip line filter further includes a second microstrip line resonator and a third microstrip line resonator, and the first electrode layer further includes a fourth electrode and a fifth electrode, wherein the second microstrip line resonator is the fourth electrode and the third microstrip line resonator is the fifth electrode; The fourth electrode extends along a first direction and has an insulating gap between it and the third electrode in a second direction. The third electrode extends in the first direction. The first direction and the second direction are parallel to the plane of the substrate, and the first direction and the second direction are different. In the second direction, the third microstrip line resonator is located on the side of the second microstrip line resonator away from the first microstrip line resonator, and the fifth electrode extends along the first direction and has an insulating gap between it and the fourth electrode in the second direction.

8. The hybrid filter according to claim 1, characterized in that, The acoustic filter includes at least two acoustic resonators, which are connected in parallel or in series. Alternatively, the acoustic filter may include at least three acoustic resonators, some of which are connected in parallel and some in series.

9. The hybrid filter according to claim 1, characterized in that, The electromagnetic filter is a stripline filter, which includes a first stripline resonator, and the third electrode is a component of the first stripline resonator. Alternatively, the electromagnetic filter is a substrate integrated waveguide filter, which includes a first substrate integrated waveguide resonator, and the third electrode is a component of the first substrate integrated waveguide resonator.

10. The hybrid filter according to claim 1, characterized in that, A second electrode layer is formed on the second side surface of the substrate, and the second side of the substrate is opposite to the first side of the substrate; the substrate has a conductive via penetrating the substrate; The second electrode layer includes a first lead-out terminal and a second lead-out terminal. The first lead-out terminal is the input terminal of the hybrid filter and is electrically connected to the input terminal of the electromagnetic filter through the conductive via. The second lead-out terminal is the output terminal of the hybrid filter and is electrically connected to the output terminal of the acoustic filter through the conductive via.

11. The hybrid filter according to claim 10, characterized in that, The second electrode layer also includes a ground electrode layer for providing a ground signal.

12. The hybrid filter according to claim 1, characterized in that, The substrate is a silicon substrate.

13. A radio frequency front-end module, characterized in that, include: The hybrid filter according to any one of claims 1-12.

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