Bulk acoustic wave filter, multiplexer and communication equipment

Abstract

The utility model provides a bulk acoustic wave filter, a multiplexer and communication equipment, and relates to the technical field of microwave devices. The bulk acoustic wave filter comprises a plurality of resonant branches which are electrically connected, each resonant branch comprises two resonant cavities which are oppositely arranged, the angle of the opposite cambered surfaces of the two resonant cavities on the same resonant branch is a first radian, the angle of the opposite cambered surfaces of the two resonant cavities on different resonant branches is a second radian, and the first radian is larger than the second radian. The first radian is smaller than the second radian. According to the bulk acoustic wave filter, through the arrangement, secondary harmonics can be reduced, harm caused by the secondary harmonics is avoided, the occupied area of the resonant cavity in the bulk acoustic wave filter is saved, and application of the bulk acoustic wave filter in a small scene is facilitated.

Description

Technical Field

[0001] The present application relates to the technical field of microwave devices, and in particular to a bulk acoustic wave filter, a multiplexer and a communication device. Background Art

[0002] Body sound wave is a device used to filter human sound signals. It can filter the sound according to the frequency characteristics of human sound waves, remove noise and interference signals, and thus improve the quality of speech recognition and voice communication.

[0003] BAW filters are composed of multiple BAW resonators, which are made by the longitudinal resonance of piezoelectric thin films in the thickness direction. In mobile phone communications and high-speed serial data applications, BAW resonators have become a viable alternative to acoustic wave devices and quartz crystal resonators, making RF front-end thin-film BAW filters / duplexers have superior filtering characteristics, such as low insertion loss, steep transition band, strong anti-static discharge capability, etc. In BAW filters, BAW resonators need to be distributed in a suitable topological structure. Utility Model Content

[0004] In view of the above-mentioned deficiencies in the prior art, the present application provides a bulk acoustic wave filter, a multiplexer 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, comprising: a plurality of electrically connected resonant branches, each resonant branch comprising: two resonant cavities arranged opposite to each other, the angle of the relative arc surfaces of the two resonant cavities on the same resonant branch being a first radian, the angle of the relative arc surfaces of the two resonant cavities on different resonant branches being a second radian, and the first radian being smaller than the second radian.

[0007] Optionally, the multiple resonant branches include: at least one series resonant branch, and the opposite arc surfaces of two resonant cavities in each series resonant branch are connected in series.

[0008] Optionally, the multiple resonant branches include: at least one parallel resonant branch, and the opposite arc surfaces of two resonant cavities in each parallel resonant branch are connected in parallel.

[0009] Optionally, a connection end of an opposite arc surface of a resonant cavity on each series resonant branch is connected in series with a connection end of an opposite arc surface of another resonant cavity on the series resonant branch through a single connecting line.

[0010] Optionally, a plurality of connection ends of the relative arc surface of one resonant cavity on each parallel resonant branch are respectively connected to a plurality of connection ends of the relative arc surface of another resonant cavity on the parallel resonant branch.

[0011] Optionally, the resonant cavity is a water droplet-shaped resonant cavity.

[0012] In a second aspect, an embodiment of the present application provides a multiplexer, comprising at least: a bulk acoustic wave filter as described in any of the above embodiments.

[0013] Optionally, the multiplexer is: a duplexer.

[0014] In a third aspect, an embodiment of the present application provides a communication device, comprising at least: a bulk acoustic wave filter as described in any of the above embodiments.

[0015] Optionally, the communication device is: a radio frequency front-end module, a filtering and amplifying module or a terminal device.

[0016] The beneficial effects of this application are:

[0017] The present application provides a bulk acoustic wave filter, comprising a plurality of electrically connected resonant branches, each resonant branch comprising two resonant cavities arranged opposite to each other, the angle of the relative arc surfaces of the two resonant cavities on the same resonant branch being a first arc, the angle of the relative arc surfaces of the two resonant cavities on different resonant branches being a second arc, and the first arc being smaller than the second arc.

[0018] Through the above arrangement, the second harmonic of the BAW filter can be reduced, the harm caused by the second harmonic can be avoided, and the area occupied by the resonant cavity in the BAW filter can be saved. The BAW filter has a small volume, which is conducive to the application of the BAW filter in smaller scenes. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] 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.

[0020] Figure 1 An equivalent circuit diagram of a bulk acoustic wave filter provided in an embodiment of the present application;

[0021] Figure 2 A schematic diagram of the structure of a bulk acoustic wave filter provided in an embodiment of the present application;

[0022] Figure 3 A schematic structural diagram of a bulk acoustic wave filter provided in yet another embodiment of the present application;

[0023] Figure 4 A schematic diagram of the connection of the resonant cavity on the series resonant branch provided in an embodiment of the present application;

[0024] Figure 5 A schematic diagram of the connection of the resonant cavity on the parallel resonant branch provided in an embodiment of the present application.

[0025] Explanation of the reference numerals: 11, first connection terminal; 12, second connection terminal; 13, third connection terminal; 14, fourth connection terminal. DETAILED DESCRIPTION

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] The BAW filter provided in the present application is specifically described below through multiple examples in conjunction with the accompanying drawings.

[0033] Figure 1 is an equivalent circuit diagram of a bulk acoustic wave filter provided in an embodiment of the present application, Figure 1 In the figure, resistor R1 is the input resistance value of the BAW filter, resistor R2 is the output resistance value of the BAW filter, and the resonant cavity is equivalent to a capacitor. Figure 1 It can be seen that, without considering the loss term, the BAW filter of the present application can be equivalent to a basic circuit diagram of a resonant circuit composed of an inductor and a capacitor.

[0034] Figure 2 The schematic diagram of the structure of the bulk acoustic wave filter provided in the embodiment of the present application is shown in FIG. Figure 1 and Figure 2 The BAW filter of the present application comprises a plurality of electrically connected resonant branches, wherein the resonant branches comprise at least one series resonant branch, and the relative arc surfaces of the two resonant cavities on each series resonant branch are connected in series; the plurality of resonant branches also comprise at least one parallel resonant branch, and the relative arc surfaces of the two resonant cavities on each parallel resonant branch are connected in parallel. Figure 2 In the figure, except for the parallel resonant branch in the lower right corner, all other resonant branches are series resonant branches. It should be noted that Figure 1 and Figure 2 This is an example of the layout of multiple resonant branches in a bulk acoustic wave filter. It does not mean that the multiple resonant branches in a bulk acoustic wave filter can only be Figure 1 and Figure 2 Layout shown.

[0035] Whether it is a series resonant branch or a parallel resonant branch, each resonant branch includes two resonant cavities arranged opposite to each other, and the resonant cavity is a teardrop-shaped resonant cavity. The angle of the relative arc surfaces of the two resonant cavities on the same resonant branch is a first arc, and the angle of the relative arc surfaces of the two resonant cavities on different resonant branches is a second arc, and the first arc is smaller than the second arc.

[0036] Reference Figure 2 In the middle dotted box, the relative arc surface of the teardrop-shaped resonator in the same resonant branch is the first arc, which is relatively gentle; Figure 3 In the middle dotted frame portion, the angle between the relative arc surfaces of the two resonant cavities on different resonant branches is the second arc, which is larger, and the first arc is smaller than the second arc.

[0037] like Figure 4 As shown, the connection relationship between the resonant cavities on the series resonant branches is that a connection end (denoted as the first connection end 11) of the relative arc surface of a resonant cavity on each series resonant branch is connected in series with a connection end (denoted as the second connection end 12) of the relative arc surface of another resonant cavity on the series resonant branch through a single connecting line.

[0038] like Figure 5 As shown, the connection relationship between the resonant cavities on the parallel resonant branches is that multiple connection ends (denoted as third connection ends 13) of the relative arc surface of a resonant cavity in each parallel resonant branch are respectively connected to multiple connection ends (denoted as fourth connection ends 14) of the relative arc surface of another resonant cavity on the parallel resonant branch.

[0039] Based on the BAW filter provided in the above embodiments, the present application further provides a multiplexer, comprising at least the BAW filter provided in any of the above embodiments. A multiplexer is a device having a single input port and multiple output ports. Specifically, the multiplexer can be, for example, a duplexer, that is, having one input port and one output port.

[0040] 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.

[0041] In summary, the present application provides a bulk acoustic wave filter, comprising a substrate and a plurality of resonant branches arranged on the substrate, such as Figure 4 and Figure 5 The multiple resonant cavities on each resonant branch are connected in sequence to form a connecting ring, which achieves the suppression of the second harmonic and avoids the damage caused by the second harmonic to the circuit. In addition, since the resonant cavity is in the shape of a teardrop, the volume of the bulk acoustic wave filter is reduced. Setting the bulk acoustic wave filter of the present application in a multiplexer or communication equipment is beneficial to reducing the usage area and is suitable for more usage scenarios.

[0042] 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 shall be subject to the protection scope of the claims.

Claims

1. A bulk acoustic wave filter, characterized in that: include: Multiple electrically connected resonant branches, each resonant branch includes: two resonant cavities arranged opposite to each other, the angle of the relative arc surfaces of the two resonant cavities on the same resonant branch is a first arc, the angle of the relative arc surfaces of the two resonant cavities on different resonant branches is a second arc, and the first arc is smaller than the second arc.

2. The bulk acoustic wave filter according to claim 1, characterized in that The multiple resonant branches include: at least one series resonant branch, and the opposite arc surfaces of two resonant cavities on each series resonant branch are connected in series.

3. The bulk acoustic wave filter according to claim 1, wherein: The multiple resonant branches include: at least one parallel resonant branch, and the opposite arc surfaces of two resonant cavities on each parallel resonant branch are connected in parallel.

4. The bulk acoustic wave filter according to claim 2, characterized in that A connection end of the opposite arc surface of a resonant cavity on each series resonant branch is connected in series with a connection end of the opposite arc surface of another resonant cavity on the series resonant branch through a single connecting line.

5. The bulk acoustic wave filter according to claim 3, characterized in that The multiple connection ends of the relative arc surface of one resonant cavity in each parallel resonant branch are respectively connected to the multiple connection ends of the relative arc surface of another resonant cavity in the parallel resonant branch.

6. The bulk acoustic wave filter according to claim 1, wherein: The resonant cavity is a water drop-shaped resonant cavity.

7. A multiplexer, characterized in that: At least: A bulk acoustic wave filter as claimed in any one of claims 1 to 6.

8. The multiplexer according to claim 7, characterized in that: The multiplexer is a duplexer.

9. A communication device, characterized in that: At least: A bulk acoustic wave filter as claimed in any one of claims 1 to 6.

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.

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