Bulk acoustic wave filter and communication equipment
By adopting a combination structure of multiple reverse-connected resonant branches and balanced bridges in the bulk acoustic wave filter, the problem of insufficient second harmonic suppression effect in the prior art is solved, and more efficient second harmonics are achieved Suppression meets the design requirements of bulk acoustic wave filters and exceeds the nonlinear suppression effect of surface acoustic wave filters.
Patent Information
- Application Number
- CN202411333056.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-24
- Publication Date
- 2025-01-10
AI Technical Summary
In the prior art, the second harmonic suppression effect of the filter is weak, and cannot meet the design requirements of the bulk acoustic wave filter, affecting the signal-to-noise ratio and power bearing of the communication link.
Design a bulk acoustic wave filter, including multiple resonant branches connected in reverse direction, each branch contains at least two identical bulk acoustic wave resonators, and the filtering is added by combining in reverse series and inverse parallel modes. The area of the device is to suppress the second harmonics and further suppress it through the balance bridge at the output port.
Effectively suppress the second harmonics of the bulk acoustic wave filter, meet or exceed the design requirements, and reduce the power density, avoid the harm of the second harmonics to the communication equipment. The nonlinear suppression effect is close to or even exceeds that of the surface acoustic wave filter. Design requirements.
Smart Images
Figure CN119298874A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of microwave devices, and in particular to a bulk acoustic wave filter and a communication device. Background Art
[0002] A filter is a device used to eliminate communication interference. Its function is to obtain a specific frequency or eliminate a specific frequency. The high-order harmonics of the filter will affect the signal-to-noise ratio, power carrying capacity and communication efficiency of the communication link. Therefore, it is usually necessary to limit the second harmonic intensity of the filter during microwave communication.
[0003] Currently, the commonly used method for suppressing the second harmonic is to increase the area of the resonator in the filter. However, this method has a weak effect on suppressing the second harmonic of the filter and cannot meet the design requirements of the Bulk Acoustic Wave (BAW) filter. Summary of the invention
[0004] In view of the above-mentioned deficiencies in the prior art, the present application provides a bulk acoustic wave filter and a communication device to solve the problems existing in the prior art.
[0005] The technical solution adopted in the embodiment of the present application is as follows:
[0006] In a first aspect, an embodiment of the present application provides a bulk acoustic wave filter, the bulk acoustic wave filter comprising: an input port, an output port, and a plurality of electrically connected resonant branches; the input ends of the plurality of resonant branches are connected to the input port, and the output ends of the plurality of resonant branches are connected to the output port;
[0007] Each resonant branch includes at least two BAW resonators which are reversely connected and have the same resonant cavity.
[0008] Optionally, the plurality of resonance branches include: at least one first resonance branch, and each first resonance branch includes: at least two first bulk acoustic wave resonators connected in reverse series.
[0009] Optionally, bottom electrodes of two adjacent first BAW resonators connected in reverse series are connected, and top electrodes of the two adjacent first BAW resonators are connected.
[0010] Optionally, if the number of the first resonant branches is at least two, the numbers of first BAW resonators connected in reverse series on different first resonant branches are the same or different.
[0011] Optionally, the plurality of resonant branches further include: at least one second resonant branch, the second resonant branch including: at least two second bulk acoustic wave resonators connected in reverse parallel.
[0012] Optionally, a top electrode of one second BAW resonator and a bottom electrode of the other second BAW resonator of two adjacent second BAW resonators connected in anti-parallel are connected.
[0013] Optionally, if the number of the second resonant branches is at least two, the numbers of the anti-parallel second BAW resonators on different second resonant branches are the same or different.
[0014] Optionally, the BAW filter further comprises: a balanced bridge;
[0015] The output ends of the multiple resonant branches are connected to the output port through the balanced bridge.
[0016] In a second aspect, an embodiment of the present application provides a communication device, comprising at least: the bulk acoustic wave filter described in the above embodiment.
[0017] Optionally, the communication device is: a radio frequency front-end module, a filtering and amplifying module or a terminal device.
[0018] The beneficial effects of the present application are as follows: the present application provides a bulk acoustic wave filter, comprising an input port, an output port, and a plurality of electrically connected resonant branches; the input ends of the plurality of resonant branches are connected to the input port, and the output ends of the plurality of resonant branches are connected to the output port; each resonant branch comprises: at least two bulk acoustic wave resonators which are reversely connected and have the same resonant cavity.
[0019] Through the above-mentioned setting, the second harmonic of the bulk acoustic wave filter (BAW) can be effectively suppressed, the harm caused by the second harmonic can be avoided, and the design requirements of the bulk acoustic wave filter are met. In addition, the nonlinear suppression of the present application is close to or even exceeds the design requirements of the surface acoustic wave filter (Surface Acoustic Wave, SAW). BRIEF DESCRIPTION OF THE DRAWINGS
[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.
[0021] Figure 1 A schematic diagram of the topological structure of a bulk acoustic wave filter provided in an embodiment of the present application;
[0022] Figure 2 A schematic diagram of reverse series connection provided in an embodiment of the present application;
[0023] Figure 3 A schematic diagram of reverse parallel connection provided in an embodiment of the present application;
[0024] Figure 4 A schematic diagram of the topological structure of a bulk acoustic wave filter provided in another embodiment of the present application;
[0025] Figure 5 A schematic diagram of the second harmonic suppression effect provided in an embodiment of the present application;
[0026] Figure 6 A schematic diagram of a reverse series connection and a reverse parallel connection provided in an embodiment of the present application;
[0027] Figure 7 A schematic diagram of the topological structure of a bulk acoustic wave filter provided in yet another embodiment of the present application. DETAILED DESCRIPTION
[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments.
[0029] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.
[0030] In the description of the present application, it should be noted that if the terms "upper", "lower", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, or is the orientation or position relationship in which the product of the application is usually placed when used. It is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.
[0031] In addition, the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.
[0032] In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "disposed" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection, it can be a direct connection, it can be an indirect connection through an intermediate medium, and it can be the internal communication of two elements. For those skilled in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.
[0033] It should be noted that, in the absence of conflict, the features in the embodiments of the present application may be combined with each other.
[0034] The BAW filter provided in the present application is specifically described below through multiple examples in conjunction with the accompanying drawings.
[0035] Figure 1 A schematic diagram of the topological structure of a bulk acoustic wave filter provided in an embodiment of the present application is shown in FIG. Figure 1 As shown, the BAW filter includes: an input port, an output port, and a plurality of electrically connected resonant branches; the input ends of the plurality of resonant branches are connected to the input port, and the output ends of the plurality of resonant branches are connected to the output port. The input port and the output port are respectively used to connect external devices, such as amplifiers, antennas, switches, etc.
[0036] Each resonant branch includes at least two BAW resonators that are reversely connected and have the same resonant cavity. The same resonant cavity means that the area and shape of the BAW resonators are exactly the same; reverse connection means that the phases between each two adjacent BAW resonators are reversed, and because the resonant cavities of the two BAW resonators are the same, the phases are reversed and the sizes are equal.
[0037] In summary, in the BAW filter provided by the present application, at least two BAW resonators are arranged on each resonant branch, and the phases of at least two BAW resonators are anti-phase and equal in size, which plays a role in suppressing the second harmonic. In addition, at least two BAW resonators are arranged on each resonant branch, which also increases the area of the filter, reduces the power density, and further suppresses the second harmonic.
[0038] Continue to refer Figure 1 The multiple resonance branches include at least one first resonance branch 11, and each first resonance branch includes: at least two first BAW resonators connected in reverse series. The bottom electrodes of two adjacent first BAW resonators connected in reverse series are connected, and the top electrodes of two adjacent first BAW resonators are connected, that is, on the first resonance branch, between two adjacent BAW resonators, the bottom electrodes are connected to the bottom electrodes, and the top electrodes are connected to the top electrodes.
[0039] Optionally, at least two first BAW resonators connected in reverse series on the first resonant branch may be, for example, Figure 2 As shown, two BAW resonators form an anti-series connection, or three BAW resonators form a three-stage anti-series connection, or four BAW resonators form a four-stage anti-series connection.
[0040] Figure 2 This is only an exemplary description of the first resonant branch and does not represent a limitation on the reverse series connection method. In fact, as long as the number of resonators in reverse series is two or more, and if the number of first resonant branches is at least two, the number of reverse-series first BAW resonators on different first resonant branches can be the same or different.
[0041] Continue to refer Figure 1 The multiple resonance branches also include at least one second resonance branch 12, and the second resonance branch includes: at least two second BAW resonators connected in reverse parallel, wherein, in two adjacent second BAW resonators connected in reverse parallel, the top electrode of one second BAW resonator is connected to the bottom electrode of another second BAW resonator, and the bottom electrode of one second BAW resonator is connected to the top electrode of another second BAW resonator.
[0042] Optionally, at least two second BAW resonators connected in reverse parallel on the second resonant branch may be, for example, Figure 3 As shown, two BAW resonators are connected in reverse parallel, or three BAW resonators are connected in reverse parallel in three stages, or four BAW resonators are connected in reverse parallel in four stages.
[0043] Figure 3 It is only an exemplary description of the second resonant branch and does not represent a limitation on the reverse parallel connection method. In fact, as long as the number of reverse-parallel resonators is two or more, and if the number of second resonant branches is at least two, the number of reverse-parallel second BAW resonators on different second resonant branches can be the same or different.
[0044] like Figure 4 As shown, the BAW filter may further include a balanced bridge, and the output ends of the multiple resonant branches are connected to the output port through the balanced bridge. The balanced bridge can further suppress the second harmonic and further reduce the second harmonic level.
[0045] The present application also provides a communication device, comprising at least the bulk acoustic wave filter provided by any of the above embodiments. The communication device may be a radio frequency front-end module, a filter amplifier module or a terminal device, or may be a mobile phone, a drone, a wireless router or other terminal device.
[0046] In summary, the present application provides a bulk acoustic wave filter, in which the number of resonators in each resonant branch is greater than or equal to 2, and there is no single resonator. The resonators in the bulk acoustic wave filter adopt a ladder topology, and the number of series and parallel orders is not limited, for example, 3 series and 3 parallel, 4 series and 3 parallel, 3 series and 4 parallel, 4 series and 4 parallel, 5 series and 4 parallel, etc. are all possible, which improves the flexibility of the implementation method.
[0047] like Figure 5 As shown, the present application improves the second harmonic suppression level of the bulk acoustic wave filter (BAW), avoids the damage caused by the second harmonic to the circuit, and the nonlinear suppression of the present application is close to or even exceeds the design requirements of the surface acoustic wave filter (Surface Acoustic Wave, SAW).
[0048] Finally, it should be noted that Figure 6 As shown, reverse series connection and reverse parallel connection can be used at the same time, the same connection scheme can be used at the same time, and can also be used repeatedly, and both reverse series connection and reverse parallel connection are possible, for example, Figure 7 As shown, the resonators on all resonant branches are connected in reverse series.
[0049] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.
Claims
1. A bulk acoustic wave filter, characterized in that: The BAW filter comprises: an input port, an output port, and a plurality of electrically connected resonant branches; the input ends of the plurality of resonant branches are connected to the input port, and the output ends of the plurality of resonant branches are connected to the output port; Each resonant branch includes at least two BAW resonators which are reversely connected and have the same resonant cavity.
2. The bulk acoustic wave filter according to claim 1, characterized in that The multiple resonance branches include: at least one first resonance branch, and each first resonance branch includes: at least two first bulk acoustic wave resonators connected in reverse series.
3. The bulk acoustic wave filter according to claim 2, characterized in that The bottom electrodes of two adjacent first BAW resonators connected in reverse series are connected, and the top electrodes of the two adjacent first BAW resonators are connected.
4. The bulk acoustic wave filter according to claim 2, characterized in that If the number of the first resonant branches is at least two, the numbers of first BAW resonators connected in reverse series on different first resonant branches are the same or different.
5. The bulk acoustic wave filter according to claim 1 or 2, characterized in that: The plurality of resonance branches further include: at least one second resonance branch, wherein the second resonance branch includes: at least two second bulk acoustic wave resonators connected in reverse parallel.
6. The bulk acoustic wave filter according to claim 5, characterized in that The top electrode of one of the two adjacent second BAW resonators connected in reverse parallel is connected to the bottom electrode of the other second BAW resonator.
7. The bulk acoustic wave filter according to claim 5, characterized in that If the number of the second resonant branches is at least two, the numbers of the anti-parallel second BAW resonators on different second resonant branches are the same or different.
8. The bulk acoustic wave filter according to claim 1, wherein: The bulk acoustic wave filter further comprises: a balanced bridge; The output ends of the multiple resonant branches are connected to the output port through the balanced bridge.
9. A communication device, characterized in that: At least: A bulk acoustic wave filter as claimed in any one of claims 1 to 8.
10. The communication device according to claim 9, characterized in that The communication device is: a radio frequency front-end module, a filtering and amplifying module or a terminal device.