Radio frequency filter and radio frequency module

Abstract

The invention relates to the technical field of radio frequency filters, and particularly provides a radio frequency filter and a radio frequency module, and the radio frequency filter comprises a plurality of function module layers which are stacked in the vertical direction, first electromagnetic shielding layers are arranged between the adjacent functional module layers, on the bottom surface of the bottommost functional module layer and on the top surface of the topmost functional module layer; the radio frequency filter can effectively solve the problems that signal crosstalk of adjacent function modules and mutual interference of generated electromagnetic interference cannot be improved at the same time, and the integration level and the space utilization rate of the radio frequency filter cannot be improved.

Description

Technical Field

[0001] This application relates to the technical field of radio frequency filters, and more specifically, to a radio frequency filter and a radio frequency module. Background Art

[0002] Related radio frequency filters include multiple functional modules. The related radio frequency filters integrate multiple functional modules at the same circuit level (equivalent to laying out each functional module on the same circuit board). The related technology can improve the problem of signal crosstalk between adjacent functional modules by increasing the spacing between adjacent functional modules. However, increasing the spacing between adjacent functional modules will result in a decrease in the integration and space utilization rate of the radio frequency filter. Therefore, the related technology has problems in that it cannot simultaneously improve the signal crosstalk between adjacent functional modules and the mutual interference problem of the generated electromagnetic interference, and improve the integration and space utilization rate of the radio frequency filter.

[0003] In view of the above problems, there is currently no effective technical solution. It should be noted that the above information disclosed in this part is only used to understand the background of the inventive concept of the present invention, and therefore may include information that does not constitute the prior art. Summary of the Invention

[0004] The purpose of this application is to provide a radio frequency filter and a radio frequency module, which can effectively solve the problem that it is impossible to simultaneously improve the signal crosstalk problem between adjacent functional modules and improve the integration and space utilization rate of the radio frequency filter.

[0005] In a first aspect, this application provides a radio frequency filter, which includes: Multiple functional module layers are stacked vertically, and first electromagnetic shielding layers are provided between adjacent functional module layers, on the bottom surface of the lowermost functional module layer, and on the top surface of the uppermost functional module layer.

[0006] The radio frequency filter provided by this application can separate adjacent functional module layers by using the first electromagnetic shielding layer by providing the first electromagnetic shielding layer between adjacent functional module layers, on the bottom surface of the lowermost functional module layer, and on the top surface of the uppermost functional module layer, so as to improve the integration and space utilization rate of the radio frequency filter while improving the signal crosstalk problem between adjacent functional module layers. Therefore, this application can effectively solve the problem that it is impossible to simultaneously improve the signal crosstalk problem between adjacent functional modules and improve the integration and space utilization rate of the radio frequency filter.

[0007] Optionally, the thickness of the first electromagnetic shielding layer near the edge of the functional module layer is less than the thickness of the first electromagnetic shielding layer near the center of the functional module layer.

[0008] Since the thickness of the first electromagnetic shielding layer near the edge of the functional module layer in this technical solution is less than that of the first electromagnetic shielding layer near the center of the functional module layer, that is, the thickness of the first electromagnetic shielding layer gradually changes, and the change in the thickness of the first electromagnetic shielding layer can achieve a gradual impedance matching, increase the number of reflections of electromagnetic waves in the first electromagnetic shielding layer, and extend the propagation path of electromagnetic waves, so as to reduce the reflection of electromagnetic waves at the interface and dissipate the energy of electromagnetic waves during multiple reflections. Therefore, this technical solution can improve the electromagnetic interference shielding effect of the first electromagnetic shielding layer and enable the first electromagnetic shielding layer to effectively shield high-frequency electromagnetic interference, and this technical solution can also optimize the structural space of the first electromagnetic shielding layer and reduce the weight of the first electromagnetic shielding layer, thereby further improving the integration and space utilization rate of the radio frequency filter.

[0009] Optionally, the thickness of the first electromagnetic shielding layer is 400 - 600 nm.

[0010] Optionally, the material of the first electromagnetic shielding layer is aluminum alloy.

[0011] Optionally, the radio frequency filter includes at least three functional module layers, and the three functional module layers are a filtering layer, a modulation layer, and a signal processing layer respectively.

[0012] Optionally, the filtering layer includes vertically stacked bulk acoustic wave resonators, capacitors, and inductors, and a third electromagnetic shielding layer is also provided between the bulk acoustic wave resonators, capacitors, and inductors.

[0013] Since a third electromagnetic shielding layer is also provided between the bulk acoustic wave resonators, capacitors, and inductors in this technical solution, this technical solution can effectively avoid the situation of signal crosstalk between the bulk acoustic wave resonators, capacitors, and inductors due to the absence of electromagnetic shielding measures between the bulk acoustic wave resonators, capacitors, and inductors.

[0014] Optionally, the bulk acoustic wave resonator includes a substrate, a support layer, a bottom electrode, a piezoelectric layer, and a top electrode connected in sequence from bottom to top, and an acoustic mirror is provided on the substrate directly below the bottom electrode.

[0015] Optionally, the material of the piezoelectric layer is aluminum nitride.

[0016] This technical solution selects aluminum nitride as the material of the piezoelectric layer. Since aluminum nitride has excellent piezoelectric properties and high-frequency characteristics, as well as the advantages of high conductivity and low loss, this technical solution can effectively improve the resonance frequency, mechanical properties, frequency response speed, and signal transmission stability of the radio frequency filter. And because aluminum nitride also has excellent thermal conductivity, this technical solution can accelerate heat dissipation by selecting aluminum nitride as the material of the piezoelectric layer to ensure the thermal stability of the radio frequency filter during long-term operation.

[0017] Optionally, the modulation layer includes a vertically stacked modulator, demodulator, and mixer, and a third electromagnetic shielding layer is further provided between the modulator, demodulator, and mixer.

[0018] Since a third electromagnetic shielding layer is further provided between the modulator, demodulator, and mixer in this technical solution, this technical solution can effectively avoid the situation of signal crosstalk between the modulator, demodulator, and mixer caused by the absence of electromagnetic shielding measures between the modulator, demodulator, and mixer.

[0019] In a second aspect, the present application further provides a radio frequency module, which includes a radio frequency filter provided in the first aspect above.

[0020] The radio frequency module provided by the present application can separate adjacent functional module layers by using the first electromagnetic shielding layer in such a way that the first electromagnetic shielding layer is provided between adjacent functional module layers, on the bottom surface of the bottommost functional module layer, and on the top surface of the topmost functional module layer, so as to improve the integration degree and space utilization rate of the radio frequency filter while improving the signal crosstalk problem between adjacent functional module layers. Therefore, the present application can effectively solve the problem that it is impossible to simultaneously improve the signal crosstalk problem between adjacent functional modules and improve the integration degree and space utilization rate of the radio frequency filter.

[0021] As can be seen from the above, the radio frequency filter and radio frequency module provided by the present application can separate adjacent functional module layers by using the first electromagnetic shielding layer in such a way that the first electromagnetic shielding layer is provided between adjacent functional module layers, on the bottom surface of the bottommost functional module layer, and on the top surface of the topmost functional module layer, so as to improve the integration degree and space utilization rate of the radio frequency filter while improving the signal crosstalk problem between adjacent functional module layers. Therefore, the present application can effectively solve the problem that it is impossible to simultaneously improve the signal crosstalk problem between adjacent functional modules and improve the integration degree and space utilization rate of the radio frequency filter. Description of the Drawings

[0022] Figure 1 It is a schematic cross-sectional structure diagram of a radio frequency filter provided by an embodiment of the present application.

[0023] Figure 2 It is a schematic cross-sectional structure diagram of a filtering layer provided by an embodiment of the present application.

[0024] Figure 3 It is a schematic cross-sectional structure diagram of a modulation layer provided by an embodiment of the present application.

[0025] Figure 4 It is a schematic cross-sectional structure diagram of a signal processing layer provided by an embodiment of the present application.

[0026] Reference numerals: 1, functional module layer; 2, first electromagnetic shielding layer; 3, filtering layer; 31, bulk acoustic wave resonator; 32, capacitor; 33, inductor; 311, substrate; 312, support layer; 313, bottom electrode; 314, piezoelectric layer; 315, top electrode; 316, acoustic mirror; 4, modulation layer; 41, modulator; 42, demodulator; 43, mixer; 5, signal processing layer; 51, amplifier; 52, signal processing circuit; 53, noise suppression module; 6, second electromagnetic shielding layer; 7, third electromagnetic shielding layer. Detailed implementation manners

[0027] Next, the technical solutions in the embodiments of the present application will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and illustrated herein can be arranged and designed in various different configurations. Therefore, the detailed description of the embodiments of the present application provided in the accompanying drawings below is not intended to limit the scope of the present application claimed, but merely represents selected embodiments of the present application. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative efforts fall within the scope of protection of the present application.

[0028] It should be noted that: similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of the present application, the terms "first", "second", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0029] In a first aspect, as Figures 1 - 4 shown, the present application provides a radio frequency filter, which includes: A plurality of functional module layers 1 are stacked in the vertical direction, and first electromagnetic shielding layers 2 are provided between adjacent functional module layers 1, on the bottom surface of the lowermost functional module layer 1, and on the top surface of the uppermost functional module layer 1.

[0030] Among them, the functional module layer 1 of this embodiment can be the functional module in an existing radio frequency filter. The first electromagnetic shielding layer 2 of this embodiment can be a layer structure made of a metal material or a magnetic material. The first electromagnetic shielding layer 2 can play a role in shielding electromagnetic interference. Since the first electromagnetic shielding layer 2 is provided between adjacent functional module layers 1, on the bottom surface of the bottommost functional module layer 1, and on the top surface of the topmost functional module layer 1, that is, adjacent functional module layers 1 are separated by the first electromagnetic shielding layer 2, there will be no signal crosstalk between adjacent functional module layers 1, and the electromagnetic interference generated by one functional module layer 1 will not interfere with another functional module layer 1. And because there is no signal crosstalk problem between adjacent functional module layers 1, this embodiment can reduce the spacing between adjacent functional module layers 1 by stacking multiple functional module layers 1 in the vertical direction. That is, this embodiment is equivalent to reducing the spacing between adjacent functional module layers 1 when there is no signal crosstalk between adjacent functional module layers 1, thereby realizing improving the integration and space utilization rate of the radio frequency filter while improving the signal crosstalk problem between adjacent functional module layers 1.

[0031] A radio frequency filter provided by this application can separate adjacent functional module layers 1 by using the first electromagnetic shielding layer 2 by providing the first electromagnetic shielding layer 2 between adjacent functional module layers 1, on the bottom surface of the bottommost functional module layer 1, and on the top surface of the topmost functional module layer 1, so as to improve the integration and space utilization rate of the radio frequency filter while improving the signal crosstalk problem between adjacent functional module layers 1. Therefore, this application can effectively solve the problem that it is impossible to simultaneously improve the signal crosstalk between adjacent functional modules and the problem that the generated electromagnetic interferences interfere with each other, as well as the problem of improving the integration and space utilization rate of the radio frequency filter. In addition, since the functional module layer 1 of this application will not be interfered by the adjacent functional module layer 1, this application can effectively improve the anti-interference ability, signal purity, and signal quality of the functional module layer 1, thereby effectively improving the anti-interference ability, signal purity, and signal quality of the radio frequency filter.

[0032] In some preferred embodiments, the thickness of the first electromagnetic shielding layer 2 near the edge of the functional module layer 1 is less than the thickness of the first electromagnetic shielding layer 2 near the center of the functional module layer 1. This embodiment is equivalent to making the thickness of the region of the first electromagnetic shielding layer near the edge of the functional module layer 1 (equivalent to the region on the side of the functional module layer 1) less than the thickness of the region of the first electromagnetic shielding layer near the center of the functional module layer 1, that is, the thickness of the first electromagnetic shielding layer 2 decreases from its center towards its edge. Since the thickness of the first electromagnetic shielding layer 2 near the edge of the functional module layer 1 in this embodiment is less than the thickness of the first electromagnetic shielding layer 2 near the center of the functional module layer 1, that is, the thickness of the first electromagnetic shielding layer 2 changes gradually, and the change in the thickness of the first electromagnetic shielding layer 2 can achieve gradual impedance matching, increase the number of reflections of electromagnetic waves in the first electromagnetic shielding layer 2, and extend the propagation path of electromagnetic waves, so as to reduce the reflection of electromagnetic waves at the interface and dissipate the energy of electromagnetic waves during multiple reflections. Therefore, this embodiment can improve the electromagnetic interference shielding effect of the first electromagnetic shielding layer 2 and enable the first electromagnetic shielding layer 2 to effectively shield high-frequency electromagnetic interference, and this embodiment can also optimize the structural space of the first electromagnetic shielding layer 2 and reduce the weight of the first electromagnetic shielding layer 2, thereby further improving the integration degree and space utilization rate of the radio frequency filter.

[0033] In some preferred embodiments, the radio frequency filter further includes a second electromagnetic shielding layer 6, and the second electromagnetic shielding layer 6 covers the side surface of the functional module layer 1. Since the first electromagnetic shielding layer 2 in this embodiment covers the top surface and the bottom surface of the functional module layer 1, and the second electromagnetic shielding layer 6 in this embodiment covers the side surface of the functional module layer 1, that is, this embodiment is equivalent to wrapping the functional module layer 1 with an electromagnetic shielding layer. Therefore, the functional module layer 1 in this embodiment will not receive external electromagnetic interference, thereby further improving the anti-interference ability, signal purity, and signal quality of the functional module layer 1, and further improving the anti-interference ability, signal purity, and signal quality of the radio frequency filter.

[0034] In some preferred embodiments, the average thickness of the first electromagnetic shielding layer 2 near the power input terminal or the high-power signal source is greater than the average thickness of the first electromagnetic shielding layer 2 far from the power input terminal and the high-power signal source, and the average thickness of the second electromagnetic shielding layer 6 near the power input terminal or the high-power signal source is greater than the average thickness of the second electromagnetic shielding layer 6 far from the power input terminal and the high-power signal source. Since both the power input terminal and the high-power signal source can generate electromagnetic interference, this embodiment can enhance the electromagnetic shielding effect of the first electromagnetic shielding layer 2 and the second shielding layer near the power input terminal or the high-power signal source by making the average thickness of the first electromagnetic shielding layer 2 near the power input terminal or the high-power signal source greater than the thickness of the first electromagnetic shielding layer 2 far from the power input terminal and the high-power signal source and making the average thickness of the second electromagnetic shielding layer 6 near the power input terminal or the high-power signal source greater than the average thickness of the second electromagnetic shielding layer 6 far from the power input terminal and the high-power signal source, thereby effectively avoiding the problem that the functional module layer 1 in this area is affected by external electromagnetic interference due to excessive electromagnetic interference in the area near the power input terminal or the high-power signal source, and further improving the anti-interference ability, signal purity and signal quality of the radio frequency filter.

[0035] In some preferred embodiments, the thickness of the first electromagnetic shielding layer 2 is 400 - 600 nm. Preferably, the thickness of the second electromagnetic shielding layer 6 is also 400 - 600 nm. This embodiment avoids the decrease in electromagnetic shielding effect due to the too thin first electromagnetic shielding layer 2 and the second electromagnetic shielding layer 6, and the functional module layer 1 wrapped by the first electromagnetic shielding layer 2 and the second electromagnetic shielding layer 6 can still receive external electromagnetic interference, as well as the situation where the production cost and weight of the first electromagnetic shielding layer 2 and the second electromagnetic shielding layer 6 are too large and the heat dissipation performance of the first electromagnetic shielding layer 2 and the second electromagnetic shielding layer 6 is too low due to the too thick first electromagnetic shielding layer 2 and the second electromagnetic shielding layer 6 by setting the thicknesses of the first electromagnetic shielding layer 2 and the second electromagnetic shielding layer 6 to 400 - 600 nm.

[0036] In some preferred embodiments, the material of the first electromagnetic shielding layer 2 is aluminum alloy. Preferably, the materials of the first electromagnetic shielding layer 2 and the second electromagnetic shielding layer 6 in this embodiment are preferably 6061 aluminum alloy (the copper content of this aluminum alloy is 1%, the magnesium content is 1%, and the silicon content is 0.6%). This embodiment enables the radio frequency filter to maintain high stability and high reliability under high-frequency and / or high-power working conditions by selecting aluminum alloy as the material of the first electromagnetic shielding layer 2 and the second electromagnetic shielding layer 6. It should be understood that since aluminum alloy has conductivity, adjacent functional module layers 1 can be interconnected only through the first electromagnetic shielding layer 2, that is, this application does not need to set up additional interconnection structures for the interconnection of the functional module layer 1.

[0037] In some preferred embodiments, the radio frequency filter includes at least three functional module layers 1, and the three functional module layers 1 are respectively a filtering layer 3, a modulation layer 4, and a signal processing layer 5. The filtering layer 3 of this embodiment can selectively pass specific frequency signals, the modulation layer 4 of this embodiment can achieve frequency conversion of signals and modulation and demodulation of signals, and the signal processing layer 5 of this embodiment can enhance signal strength, optimize signal characteristics, and reduce the influence of noise.

[0038] In some preferred embodiments, the filtering layer 3 includes vertically stacked bulk acoustic wave resonators 31, capacitors 32, and inductors 33, and a third electromagnetic shielding layer 7 is further provided between the bulk acoustic wave resonators 31, capacitors 32, and inductors 33. Since the third electromagnetic shielding layer 7 is further provided between the bulk acoustic wave resonators 31, capacitors 32, and inductors 33 in this embodiment, this embodiment can effectively avoid the situation of signal crosstalk between the bulk acoustic wave resonators 31, capacitors 32, and inductors 33 due to the absence of electromagnetic shielding measures between the bulk acoustic wave resonators 31, capacitors 32, and inductors 33.

[0039] In some preferred embodiments, the bulk acoustic wave resonator 31 includes a substrate 311, a support layer 312, a bottom electrode 313, a piezoelectric layer 314, and a top electrode 315, which are connected in sequence from bottom to top. An acoustic mirror 316 is provided on the substrate 311 directly below the bottom electrode 313. The material of the substrate 311 in this embodiment is preferably silicon. The materials of the bottom electrode 313 and the top electrode 315 in this embodiment are preferably metal materials with high conductivity, large acoustic impedance, and large Young's modulus (such as any one or more of gold, molybdenum, ruthenium, and platinum). The material of the bottom electrode 313 in this embodiment is preferably the same as that of the top electrode 315. The material of the piezoelectric layer 314 in this embodiment is preferably aluminum nitride. Specifically, when a signal source is externally connected to the top electrode 315 and the bottom electrode 313 (equivalent to applying a voltage signal or an electrical signal to the top electrode 315 and the bottom electrode 313), an electric field is formed at both ends of the piezoelectric layer 314 to excite bulk acoustic waves (equivalent to exciting the piezoelectric layer 314 to generate longitudinal waves), thereby realizing the mutual conversion of electrical energy and mechanical energy and the frequency selection of the bulk acoustic wave resonator 31. An acoustic mirror 316 is provided on the substrate 311 in this embodiment. The acoustic mirror 316 can be an air cavity or several layers of Bragg reflection layers. Each layer of Bragg reflection layer is composed of a low acoustic impedance layer and a high acoustic impedance layer. In this embodiment, an air cavity can be formed on the substrate 311 by first etching the substrate 311 to form a groove on the substrate 311, then depositing a sacrificial layer in the groove, forming the bottom electrode 313 on the substrate 311, and finally removing the sacrificial layer based on a wet etching process. In this embodiment, several layers of Bragg reflection layers can also be formed in the groove by first etching the substrate 311 to form a groove on the substrate 311 and then forming several layers of Bragg reflection layers in the groove based on the existing Bragg reflection layer forming process. It should be understood that if the acoustic mirror 316 is an air cavity, the bulk acoustic wave resonator 31 in this embodiment essentially belongs to a film bulk acoustic resonator (FBAR). If the acoustic mirror 316 is a Bragg reflection layer, the bulk acoustic wave resonator 31 in this embodiment essentially belongs to a solid mounted resonator (SMR).

[0040] In some preferred embodiments, the material of the piezoelectric layer 314 is aluminum nitride. In this embodiment, aluminum nitride is selected as the material of the piezoelectric layer 314. Since aluminum nitride has excellent piezoelectric properties, high-frequency characteristics, high conductivity, and low loss, this embodiment can effectively improve the resonant frequency, mechanical properties, frequency response speed, and signal transmission stability of the RF filter. And since aluminum nitride also has excellent thermal conductivity, this embodiment can accelerate heat dissipation by selecting aluminum nitride as the material of the piezoelectric layer 314 to ensure the thermal stability of the RF filter during long-term operation.

[0041] In some preferred embodiments, the modulation layer 4 includes a vertically stacked modulator 41, demodulator 42, and mixer 43, and a third electromagnetic shielding layer 7 is further provided between the modulator 41, demodulator 42, and mixer 43. Since the third electromagnetic shielding layer 7 is further provided between the modulator 41, demodulator 42, and mixer 43 in this embodiment, this embodiment can effectively avoid the situation of signal crosstalk between the modulator 41, demodulator 42, and mixer 43 due to the absence of electromagnetic shielding measures between the modulator 41, demodulator 42, and mixer 43.

[0042] In some preferred embodiments, the signal processing layer 5 includes a vertically stacked amplifier 51, signal processing circuit 52, and noise suppression module 53, and a third electromagnetic shielding layer 7 is further provided between the amplifier 51, signal processing circuit 52, and noise suppression module 53. Since the third electromagnetic shielding layer 7 is further provided between the amplifier 51, signal processing circuit 52, and noise suppression module 53 in this embodiment, this embodiment can effectively avoid the situation of signal crosstalk between the amplifier 51, signal processing circuit 52, and noise suppression module 53 due to the absence of electromagnetic shielding measures between the amplifier 51, signal processing circuit 52, and noise suppression module 53.

[0043] As can be seen from the above, a radio frequency filter provided by the present application can separate adjacent functional module layers 1 by means of the first electromagnetic shielding layer 2 by arranging the first electromagnetic shielding layer 2 between adjacent functional module layers 1, on the bottom surface of the lowermost functional module layer 1, and on the top surface of the uppermost functional module layer 1, so as to improve the integration and space utilization rate of the radio frequency filter while improving the problem of signal crosstalk between adjacent functional module layers 1. Therefore, the present application can effectively solve the problem of being unable to simultaneously improve the signal crosstalk problem between adjacent functional modules and improve the integration and space utilization rate of the radio frequency filter.

[0044] In a second aspect, the present application further provides a radio frequency module, and the radio frequency module includes a radio frequency filter provided in the first aspect above.

[0045] A radio frequency module provided by the present application includes the radio frequency filter provided in the first aspect above. The principle of the radio frequency module provided in this embodiment is the same as that of the radio frequency filter provided in the first aspect above, and will not be elaborated in detail here.

[0046] As can be seen from the above, a radio frequency filter and a radio frequency module provided by the present application can separate adjacent functional module layers 1 by arranging a first electromagnetic shielding layer 2 between adjacent functional module layers 1, on the bottom surface of the lowermost functional module layer 1, and on the top surface of the uppermost functional module layer 1, so as to improve the signal crosstalk between adjacent functional module layers 1 while increasing the integration and space utilization rate of the radio frequency filter. Therefore, the present application can effectively solve the problem that it is impossible to simultaneously improve the signal crosstalk problem between adjacent functional modules and increase the integration and space utilization rate of the radio frequency filter.

[0047] In the embodiments provided by the present application, it should be understood that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

[0048] The above are only the embodiments of the present application and are not used to limit the protection scope of the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A radio frequency filter, characterized in that: The radio frequency filter comprises: A plurality of functional module layers are stacked in a vertical direction, and a first electromagnetic shielding layer is provided between adjacent functional module layers, on the bottom surface of the bottom functional module layer, and on the top surface of the top functional module layer.

2. The radio frequency filter according to claim 1, characterized in that: The thickness of the first electromagnetic shielding layer near the edge of the functional module layer is smaller than the thickness of the first electromagnetic shielding layer near the center of the functional module layer.

3. The radio frequency filter according to claim 2, characterized in that: The thickness of the first electromagnetic shielding layer is 400-600 nm.

4. The radio frequency filter according to claim 1, characterized in that: The material of the first electromagnetic shielding layer is aluminum alloy.

5. The radio frequency filter according to claim 1, characterized in that: The radio frequency filter includes at least three functional module layers, wherein the three functional module layers are a filtering layer, a modulation layer and a signal processing layer respectively.

6. The radio frequency filter according to claim 5, characterized in that: The filter layer includes a bulk acoustic wave resonator, a capacitor and an inductor which are vertically stacked, and a third electromagnetic shielding layer is provided between the bulk acoustic wave resonator, the capacitor and the inductor.

7. The radio frequency filter according to claim 6, characterized in that: The BAW resonator comprises a substrate, a support layer, a bottom electrode, a piezoelectric layer and a top electrode which are sequentially connected from bottom to top. An acoustic reflector is arranged on the substrate and is located directly below the bottom electrode.

8. The radio frequency filter according to claim 7, characterized in that: The material of the piezoelectric layer is aluminum nitride.

9. The radio frequency filter according to claim 5, characterized in that: The modulation layer includes a modulator, a demodulator and a mixer which are vertically stacked, and a third electromagnetic shielding layer is arranged between the modulator, the demodulator and the mixer.

10. A radio frequency module, characterized in that: The radio frequency module includes the radio frequency filter as described in any one of claims 1-9.

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