Bulk acoustic wave filter and electronic device
By grouping and rationally laying the resonators of the bulk acoustic wave filter, the problem of parasitic interference affecting the filter performance is solved, and the efficient area utilization and miniaturization design of the filter are realized.
Patent Information
- Application Number
- CN202410115448.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-26
- Publication Date
- 2025-07-29
AI Technical Summary
When the prior art reduces the size of the bulk acoustic wave filter, it is susceptible to parasitic interference to affect the filter performance, resulting in low area utilization.
A bulk acoustic wave filter is designed, and the shape and position of the resonator are reasonably arranged to improve area utilization by dividing N first resonators and N second resonators into two groups, and the center of the positive projection of some first resonators on the horizontal plane is located on the same straight line.
Without affecting the filter performance, the area utilization rate of bulk acoustic wave filter is significantly improved, realizing a small-scale on-chip design.
Smart Images
Figure CN120389714A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure belongs to the field of communication technologies, and particularly relates to a bulk acoustic wave filter and an electronic device. Background Art
[0002] The miniaturized on-chip design of filters is the most basic requirement for current portable mobile products. In order to further reduce the size of bulk acoustic wave filters, one is to improve the packaging form of the device, and wafer-level packaging (WLP) gradually appears in people's vision. This packaging method can reduce the chip area by about 40%. The other is to optimize the chip design during the device design process, reduce the area of the resonator or improve the layout arrangement of the filter. However, as the layout of the filter is reduced, parasitic interference will be generated, thus affecting the performance of the filter. Summary of the Invention
[0003] The present invention aims to solve at least one of the technical problems existing in the prior art, and provides a bulk acoustic wave filter and an electronic device that can greatly improve the area utilization rate of the filter without affecting the performance of the filter.
[0004] In a first aspect, the technical solution adopted to solve the technical problems of the present invention is a bulk acoustic wave filter, including N first resonators and N second resonators. The second electrode of the i-th first resonator is connected to the first electrode of the (i + 1)-th first resonator, where i ranges from 1 to (N - 1) and N ≥ 2;
[0005] The first electrode of the j-th second resonator is connected to the second electrode of the j-th first resonator, and the second electrode of the j-th second resonator is connected to the reference potential terminal; j ranges from 1 to N;
[0006] Wherein, the N second resonators are divided into two groups, and the N first resonators are located between the two groups of second resonators, and the centers of the orthographic projections of at least some of the first resonators on the horizontal plane are located on the same straight line.
[0007] In some embodiments, N = 3. The second electrode of the first first resonator is connected to the first electrode of the second first resonator, and the second electrode of the second first resonator is connected to the first electrode of the third first resonator; the first electrode of the first second resonator is connected to the second electrode of the first first resonator, the first electrode of the second second resonator is connected to the second electrode of the second first resonator, the first electrode of the third second resonator is connected to the second electrode of the third first resonator, and the second electrodes of the first second resonator, the second second resonator, and the third second resonator are all connected to the reference potential terminal;
[0008] Among them, the first second resonator and the third second resonator form a first group, the second second resonator forms a second group, and the first first resonator, the second first resonator, and the third first resonator are located between the first group and the second group.
[0009] In some embodiments, the first second resonator, the third second resonator, the first first resonator, and the third first resonator define a first region, and the second first resonator is embedded in the first region.
[0010] In some embodiments, the orthographic projections of the first second resonator and the third second resonator on the horizontal plane are both quarter-ellipses each composed of an arc edge and two straight edges;
[0011] The orthographic projections of the first first resonator, the second first resonator, and the third first resonator on the horizontal plane are all semi-ellipses each composed of an arc edge and a straight edge;
[0012] The orthographic projection of the second second resonator on the horizontal plane is a closed shape composed of two relatively arranged arcs and three straight edges.
[0013] In some embodiments, for the first first resonator and the third first resonator, the line connecting the centers of their orthographic projections on the horizontal plane is a first straight line, and the maximum distance between their orthographic projections on the horizontal plane is a first distance; for the first first resonator and the third first resonator, the line connecting the centers of their orthographic projections on the horizontal plane is a second straight line, and the maximum distance between their orthographic projections on the horizontal plane is a second distance, where
[0014] the first straight line is parallel to the second straight line, and the first distance is equal to the second distance.
[0015] In some embodiments, the arc edges of the orthographic projections of the first second resonator and the third second resonator on the horizontal plane are adjacent to each other;
[0016] The arc edges of the orthographic projections of the first first resonator and the third first resonator on the horizontal plane are adjacent to each other;
[0017] The arc edge of the orthographic projection of the second first resonator on the horizontal plane is adjacent to the arc edge of the orthographic projection of the third second resonator on the horizontal plane.
[0018] In some embodiments, for the second first resonator and the first first resonator, the line connecting the centers of their orthographic projections on the horizontal plane is a third straight line, and the third straight line has a first included angle with the second straight line.
[0019] In some embodiments, the first included angle is 10° to 35°.
[0020] In some embodiments, two arc edges of the orthographic projection of the second second resonator on the horizontal plane are oppositely arranged in the direction of the second straight line. Two ends of the first straight line edge of the orthographic projection of the second second resonator on the horizontal plane are respectively connected to the two arc edges. The second straight line edge and the third straight line edge of the second second resonator are connected and have a second included angle, where
[0021] the second straight line edge and the third straight line edge of the orthographic projection of the second second resonator on the horizontal plane are closer to the first first resonator and the third first resonator than the first straight line edge of the orthographic projection of the second second resonator on the horizontal plane.
[0022] In some embodiments, the second included angle formed by the second straight line edge and the third straight line edge of the second second resonator is 140° - 160°.
[0023] In some embodiments, the length of the orthographic projection of the second second resonator on the horizontal plane is equal to the second distance.
[0024] In some embodiments, the area of the orthographic projection of the second first resonator on the horizontal plane is equal to the area of the orthographic projection of the third first resonator on the horizontal plane, and is less than the area of the orthographic projection of the first first resonator on the horizontal plane; the area of the orthographic projection of the first first resonator on the horizontal plane is less than the area of the orthographic projection of the third second resonator on the horizontal plane; the area of the orthographic projection of the third second resonator on the horizontal plane is less than the area of the orthographic projection of the first second resonator on the horizontal plane; the area of the orthographic projection of the first second resonator on the horizontal plane is less than the area of the orthographic projection of the second second resonator on the horizontal plane.
[0025] In some embodiments, the orthographic projection of the bulk acoustic wave filter on the horizontal plane is a rectangle.
[0026] In some embodiments, the first resonator is a thin film bulk acoustic wave resonator or a solidly mounted resonator;
[0027] The second resonator is a thin film bulk acoustic wave resonator or a solidly mounted resonator.
[0028] In a second aspect, an embodiment of the present disclosure provides an electronic device, including the bulk acoustic wave filter according to any one of the above first aspects. Description of the Drawings
[0029] Figure 1 It is a schematic structural diagram of a SAW resonator in the prior art;
[0030] Figure 2 It is a schematic structural diagram of an FBAR resonator;
[0031] Figure 3 It is a schematic structural diagram of an SMR resonator;
[0032] Figure 4 It is a circuit structure diagram of a bulk acoustic wave filter;
[0033] Figure 5 It is a circuit structure diagram of a third - order bulk acoustic wave filter;
[0034] Figure 6 It is for Figure 5 a top view of a bulk acoustic wave filter with the circuit structure in
[0035] Figure 7 It is for Figure 5 a top view of a bulk acoustic wave filter with the circuit structure in
[0036] Figure 8 It is a schematic diagram of a bulk acoustic wave filter provided by an embodiment of the present disclosure;
[0037] Figure 9 It is for Figure 6 and Figure 7 the S - parameter curve graph of the wide frequency band of the corresponding 3 - order bulk acoustic wave filter;
[0038] Figure 10 It is for Figure 6 and Figure 7 the S - parameter curve graph at the center frequency of the corresponding 3 - order bulk acoustic wave filter. Specific Embodiments
[0039] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0040] Unless otherwise defined, technical terms or scientific terms used in this disclosure shall have the ordinary meanings understood by those of ordinary skill in the art to which this disclosure pertains. The terms "first", "second" and similar terms used in this disclosure do not denote any order, quantity or importance, but are only used to distinguish different components. Similarly, terms such as "a", "an" or "the" do not denote a quantity limitation, but mean that there is at least one. Terms such as "comprising" or "including" mean that the elements or objects appearing before this term cover the elements or objects listed after this term and their equivalents, without excluding other elements or objects. Terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. Terms such as "upper", "lower", "left" and "right" are only used to indicate relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.
[0041] With the rapid development of mobile communication technology, the applications of many radio frequency devices have increased significantly, and the filter market will experience explosive growth. Currently, the filtering devices applied to personal mobile terminals (such as mobile phones) are mainly piezoelectric acoustic wave filters. The resonators that make up such filters are mainly: FBAR (Film Bulk Acoustic Resonator), SMR (Solidly Mounted Resonator), SAW (Surface Acoustic Wave Resonator), where FBAR and SMR are collectively referred to as BAW (Bulk Acoustic Wave Resonator).
[0042] Figure 1 FIG. [ID] is a schematic structural diagram of a SAW resonator in the prior art. The working principle of a SAW resonator is to convert an electrical signal into an acoustic wave propagating on the surface of a piezoelectric layer through an interdigital transducer (IDT). As Figure 1 shown, the resonant frequency of a SAW resonator is determined by the spacing between the IDT electrodes, that is, fp = v / p, where p is the spacing between the IDT electrodes and v is the velocity.
[0043] The working principle of a BAW resonator is to convert an electrical signal into a bulk acoustic wave propagating in the thickness direction of a piezoelectric layer. The resonant frequency is determined by the thickness of the piezoelectric layer, that is, fp = v / 2t, where t is the thickness of the piezoelectric thin film and v is the sound velocity. Two common structures of BAW resonators include FBAR and SMR, where Figure 2 FIG. [ID] is a schematic structural diagram of an FBAR resonator, Figure 3 FIG. [ID] is a schematic structural diagram of an SMR resonator. As Figure 2As shown, the FBAR resonator includes a first substrate 101, an air gap 102, a first electrode layer 104, and a first piezoelectric thin film 103 located between the first electrode layers 104. The FBAR resonator applies a voltage through the first electrode layer 104 to convert an electrical signal into a bulk acoustic wave propagating in the thickness direction of the first piezoelectric thin film 103. As Figure 3 As shown, the SMR resonator includes a second substrate 201, a high acoustic impedance layer 2021, a low acoustic impedance layer 2022, a second piezoelectric thin film layer 203, and a second electrode layer 204. The SMR resonator applies a voltage through the second electrode layer 104 to convert an electrical signal into a bulk acoustic wave propagating in the thickness direction of the second piezoelectric thin film 203. As Figures 2-3 As shown, the difference between the two is that the FBAR uses the air gap 102 to achieve total reflection of the interface acoustic wave, and the acoustic impedance of air is approximately equal to zero; the SMR is based on the Bragg reflection layer composed of alternating high acoustic impedance layers 2021 and low acoustic impedance layers 2022 to achieve total reflection.
[0044] For a radio frequency filter, its key performance indicators include insertion loss, out-of-band rejection, and roll-off coefficient, etc. The insertion loss is often represented by the parameter IL (Insert Loss). Since the signal cannot reach the output end completely, there will definitely be energy loss when passing through the filter. The insertion loss defines this and can be expressed as the ratio of the input power Pin to the output power PL, that is, IL(dB) = 10lg(Pin / PL) = -S21, where S21 is the transmission coefficient from the input port to the output port and can be measured by a vector network analyzer. The out-of-band rejection Q is the attenuation amount outside the passband range of the filter, indicating the suppression ability for unwanted frequency signals. The roll-off coefficient, also known as the rectangularity coefficient, describes the steepness of the transition band of the filter. The steeper it is, the better the frequency selection performance of the filter, and it can be expressed by the ratio of the 60dB bandwidth to the 3dB bandwidth. BAW has the advantages of lower insertion loss, high Q value, steeper roll-off characteristics, higher frequency can be achieved, and larger power capacity compared with SAW.
[0045] In order to further reduce the size of the bulk acoustic wave filter, the embodiments of the present disclosure propose a bulk acoustic wave filter, which can greatly improve the filter area utilization rate without affecting the filter performance.
[0046] Figure 4 It is a circuit structure diagram of a bulk acoustic wave filter. As Figure 4As shown in the figure, the bulk acoustic wave filter includes N first resonators S and N second resonators P. The second electrode s2 of the i-th first resonator S is connected to the first electrode s1 of the (i + 1)-th first resonator S, where i ranges from 1 to (N - 1) and N ≥ 2. The first electrode p1 of the j-th second resonator P is connected to the second electrode s2 of the j-th first resonator S, and the second electrode p2 of the j-th second resonator P is connected to the reference potential terminal 3, where j ranges from 1 to N. Among them, the N second resonators P are divided into two groups, and the N first resonators S are located between the two groups of second resonators P, and at least part of the centers of the first resonators S projected onto the horizontal plane are located on the same straight line.
[0047] Specifically, the bulk acoustic wave filter includes an input port 1 and an output port 2. Between the input port 1 and the output port 2, there are also multiple series-connected first resonators S and multiple parallel-connected second resonators P. Among them, the numbers of the first resonators S and the second resonators P in different bulk acoustic wave filters are different. For example, the bulk acoustic wave filter can be a third-order bulk acoustic wave filter, that is, N = 3, or a second-order bulk acoustic wave filter, that is, N = 2. The bulk acoustic wave filter can also be a fourth-order bulk acoustic wave filter or a bulk acoustic wave filter of more orders, etc. The present disclosure does not limit this.
[0048] It should be noted that for the convenience of description, in all the following embodiments of the present disclosure, the area of the first resonator S mentioned refers to the area of the first resonator S projected onto the horizontal plane; the area of the second resonator P refers to the area of the second resonator P projected onto the horizontal plane. In addition, in the embodiments of the present disclosure, the area of the first resonator S can represent the size of the first resonator S. Similarly, the area of the second resonator P can represent the size of the second resonator P.
[0049] The resonant frequencies of the first resonators S with different areas (the areas projected onto the horizontal plane) are the same. Similarly, the resonant frequencies of the second resonators P with different areas (the areas projected onto the horizontal plane) are the same. That is to say, the size of the area of the first resonator S or the second resonator P projected onto the horizontal plane does not affect its resonant frequency, but different area combinations of the N first resonators S and the N second resonators P will affect the performance of the bulk acoustic wave filter. Among them, the performance of the bulk acoustic wave filter includes the insertion loss, out-of-band rejection, or roll-off coefficient of the bulk wave filter, etc., ultimately affecting the overall performance of the bulk wave filter. Therefore, there is a way of area combination for each bulk acoustic wave filter with the smallest overall occupied area of the first resonator S and the second resonator P. In the embodiments of the present disclosure, it is applicable to any area combination mode of the first resonator S and the second resonator P. For example, it can be the structure layout of the bulk acoustic wave filter on the premise of the area combination mode with the smallest overall occupied area of the first resonator S and the second resonator P; it can also be the structure layout of the bulk acoustic wave filter under other area combination modes. The present disclosure does not limit this.
[0050] In some embodiments, the combination of areas with the smallest overall occupied area of the first resonator S and the second resonator P can be obtained based on simulation. Of course, it can also be obtained by other means. For example, the overall occupied area of the first resonator S and the second resonator P is calculated through a preset algorithm to obtain the combination of areas with the smallest area. The present disclosure places no limitations thereon.
[0051] When the numbers of the first resonator S and the second resonator P in the bulk acoustic wave filter are different, in order to enable the bulk acoustic wave filter to achieve better performance, the areas of the positive projections of each first resonator S and / or second resonator P on the horizontal plane may also be different. In the prior art, regardless of how the numbers or areas of the first resonator S and the second resonator P in the bulk acoustic wave filter change, the centers of the positive projections of the N first resonators S on the horizontal plane are set to be on the same straight line, and the centers of the positive projections of the N second resonators P on the horizontal plane are set to be on another same straight line. With this design in the prior art, miniaturized on-chip design of the bulk acoustic wave filter can only be achieved by reducing the area of the first resonator S or the second resonator P, or reducing the spacing between resonators (between the first resonator S and the second resonator P, or between the first resonators S, or between the second resonators P). At the same time, reducing the area of the first resonator S or the second resonator P in the prior art will affect the performance of the bulk acoustic wave resonator, and reducing the spacing between resonators will also generate parasitic interference.
[0052] In the embodiments of the present disclosure, on the one hand, the N second resonators P are divided into two groups and are respectively arranged on both sides of the N first resonators S. In some embodiments, the embodiments of the present disclosure can divide the second resonators P into two groups according to one or more of the number of the second resonators P, the area and shape of each second resonator P and / or each first resonator S. With such a design, the second resonators P can be combined according to the areas of the second resonators P and the first resonators S, so as to more reasonably layout the second resonators P, greatly improve the area utilization rate of the bulk acoustic wave resonator, and will not affect the performance of the bulk acoustic wave resonator. In some embodiments, the second resonators P or the first resonators S with the same area can also be set to different shapes. For example, circular, square, polygonal, etc., which can be specifically set flexibly according to the area of the second resonator P or the first resonator S and the performance of the bulk acoustic wave filter.
[0053] In some embodiments, the shapes of the orthographic projections of the first resonator S and the second resonator P on the horizontal plane are at least partially elliptical. Specifically, for the ideal case of a bulk acoustic wave resonator, only the thickness-extended (TE) mode is excited, i.e., a longitudinal mechanical wave with a propagation vector in the propagation direction. Unfortunately, in addition to the desired TE mode, there are also transverse modes. Due to the existence of the transverse modes, a part of the energy incident on the bulk acoustic wave filter is not output through the output end, but is converted into heat energy or other mechanical energy, which has an adverse effect on the performance of the bulk acoustic wave filter and will introduce spurious frequencies and passband ripples. Since increasing the ratio of area to perimeter can reduce the transverse modes and thus improve the out-of-band rejection Q factor, for a given area, reducing the perimeter can weaken the transverse modes. Among geometric shapes, a circle has the largest ratio of area to perimeter, and an ellipse has the second largest ratio. However, the transverse modes of a circular bulk acoustic wave filter are quite strong. In the embodiments of the present disclosure, the shapes of the orthographic projections of the first resonator S and the second resonator P on the horizontal plane are set to be elliptical.
[0054] In some embodiments, the maximum distance between the second resonators P in the first group is equal to the maximum distance between the second resonators P in the second group. With such a design, without affecting the performance of the bulk acoustic wave filter, the area utilization rate of the bulk acoustic wave filter can be improved as much as possible.
[0055] In a second aspect, the centers of the orthographic projections of some of the N first resonators S on the horizontal plane are located on the same straight line, and the other first resonators S are reasonably arranged on this basis. For example, the first resonators S located on the same straight line and the second resonators P can define a blank area, and the other first resonators S can be embedded in this blank area. It can be understood that the first resonators S located on the same straight line and the second resonators P in the first group and the second group can respectively define a blank area, and the other first resonators S can be embedded in any of the blank areas according to the specific situation. With such a design, the area utilization rate of the bulk acoustic wave resonator can be further improved without affecting the performance of the bulk acoustic wave resonator.
[0056] In the following embodiments, only N = 3 is taken as an example for illustration, which does not limit the number of the first resonators S and the second resonators P in the bulk acoustic wave filter.
[0057] In some embodiments, N = 3. The second electrode s2 of the first first resonator S11 is connected to the first electrode s1 of the second first resonator S12, and the second electrode s2 of the second first resonator S12 is connected to the first electrode s1 of the third first resonator S13. The first electrode p1 of the first second resonator P11 is connected to the second electrode s2 of the first first resonator S11, the first electrode p1 of the second second resonator P12 is connected to the second electrode s2 of the second first resonator S12, and the first electrode p1 of the third second resonator P13 is connected to the second electrode s2 of the third first resonator S13. Moreover, the second electrodes p2 of the first second resonator P11, the second second resonator P12, and the third second resonator P13 are all connected to the reference potential terminal 3.
[0058] Among them, the first second resonator P11 and the third second resonator P13 are taken as the first group, the second second resonator P12 is taken as the second group, and the first first resonator S11, the second first resonator S12, and the third first resonator S13 are located between the first group and the second group.
[0059] Specifically, Figure 5 is a circuit structure diagram of a third-order bulk acoustic wave filter. Figure 6 is for the Figure 5 top view of the bulk acoustic wave filter with the circuit structure in the prior art. Figure 7 is for the Figure 5 top view of the bulk acoustic wave filter with the circuit structure in the embodiments of the present disclosure. As Figures 5-7 shown, the bulk acoustic wave filter is a third-order bulk acoustic wave filter, including three serially connected first resonators and three parallely connected second resonators.
[0060] As Figure 6 shown, in the prior art, P11, P12, and P13 are arranged on the same straight line, and S11, S12, and S13 are arranged on the same straight line. It can be seen from Figure 6 that such an arrangement in the prior art results in a large amount of wasted area (i.e., the blank area in Figure 6 ) in the bulk wave filter, and the overall area of the bulk wave filter is too large, which is not conducive to realizing the miniaturized on-chip design of the bulk acoustic wave filter.
[0061] As Figure 7As shown, in the embodiments of the present disclosure, the second resonator P is divided into two groups. Since the area of P12 is relatively large and the areas of P11 and P13 are relatively small. Therefore, in the embodiments of the present disclosure, P11 and P13 are divided into the first group, and P12 is divided into the second group. S11, S12, and S13 are arranged between the first group and the second group. With such a design, without affecting the performance of the bulk acoustic wave filter, the area utilization rate of the bulk acoustic wave filter is greatly improved. It can be understood that according to the sizes of the areas of the respective second resonators P in the bulk acoustic wave filter, there can be other division methods for the second resonator P, and the present disclosure does not limit this.
[0062] In some embodiments, the first second resonator P11, the third second resonator P13, the first first resonator S11, and the third first resonator S13 define a first region, and the second first resonator S12 is embedded in the first region.
[0063] Specifically, still referring to Figure 7 , the area of the first region is larger than the area of S12. In order to make the best use of the area of the bulk acoustic wave filter as much as possible, S12 is embedded in this first region, and such a design will not affect the cascading relationship between the respective first resonators and the respective second resonators.
[0064] In some embodiments, the orthographic projections of the first second resonator P11 and the third second resonator P13 on the horizontal plane are both quarter-ellipses formed by an arc side and two straight sides; the orthographic projections of the first first resonator S11, the second first resonator S12, and the third first resonator S13 on the horizontal plane are all semi-ellipses formed by an arc side and a straight side; the orthographic projection of the second second resonator P12 on the horizontal plane is a closed shape formed by two relatively arranged arcs and three straight sides.
[0065] Specifically, as described above, increasing the ratio of the area to the perimeter of the bulk acoustic wave filter can reduce the transverse mode, thereby improving the Q factor. Therefore, for a given area, reducing the perimeter can weaken the transverse mode. Among given areas, the ratio of the area to the perimeter of a circle is the largest, and an ellipse has the second largest ratio. However, the transverse mode of a circular bulk acoustic wave filter is quite strong, so an ellipse is a good choice. Further, according to factors such as the number of resonators, the specific area and position of each resonator, etc., its shape is flexibly adjusted on the basis of an ellipse to be a quarter-ellipse, a semi-ellipse, or an approximate ellipse.
[0066] Figure 8 It is a schematic diagram of a bulk acoustic wave filter provided by the embodiments of the present disclosure, as shown in Figure 8As shown, in some embodiments, for the first second resonator P11 and the third second resonator P13, the line connecting the centers of their orthographic projections on the horizontal plane is the first straight line m1, and the maximum distance between their orthographic projections on the horizontal plane is the first distance d1; for the first first resonator S11 and the third first resonator S13, the line connecting the centers of their orthographic projections on the horizontal plane is the second straight line m2, and the maximum distance between their orthographic projections on the horizontal plane is the second distance d2, where the first straight line m1 is parallel to the second straight line m2, and the first distance d1 is equal to the second distance d2.
[0067] Specifically, P11, P13, S11, and S13 form a rectangle, and the four are respectively arranged at the four right angles of the rectangle. Such a design can greatly improve the area utilization rate of the bulk acoustic wave filter.
[0068] In some embodiments, the arc sides of the orthographic projections of the first second resonator P11 and the third second resonator P13 on the horizontal plane are adjacent; the arc sides of the orthographic projections of the first first resonator S11 and the third first resonator S13 on the horizontal plane are adjacent; the arc side of the orthographic projection of the second first resonator S12 on the horizontal plane is adjacent to the arc side of the orthographic projection of the third second resonator P13 on the horizontal plane.
[0069] Specifically, in some embodiments, the four sides of the first resonator S and the second resonator P are set as straight lines instead of curved shapes. Such a design can save area as much as possible and further greatly improve the area utilization rate of the bulk acoustic wave filter. Therefore, the first resonator S and the second resonator P in the embodiments of the present disclosure have at least one straight side and are arranged on the four sides.
[0070] In some embodiments, for the second first resonator S12 and the first first resonator S11, the line connecting the centers of their orthographic projections on the horizontal plane is the third straight line m3, and the third straight line m3 and the second straight line m3 have a first included angle α1.
[0071] Specifically, S12 is embedded in the blank area defined by P11, P13, S11, and S13, where the size of the first included angle α1 can be flexibly set according to the area of S12 to maximize the area utilization rate of the bulk acoustic wave filter.
[0072] In some embodiments, the first included angle α1 is 10° - 35°.
[0073] Specifically, the first angle α1 between S11 and S12 is 10°-35°, which depends on the area of S12. A first area threshold is set. If the area of S12 < the first area threshold, the first angle between S11 and S12 is 10°-22°; if the area of S12 > the first area threshold, the first angle between S11 and S12 is 23°-35°.
[0074] In some embodiments, the two arc edges of the orthographic projection of the second second resonator P12 on the horizontal plane are arranged oppositely in the direction of the second straight line m2. The two ends of the first straight line edge of the orthographic projection of the second second resonator P12 on the horizontal plane are respectively connected to the two arc edges. The second straight line edge and the third straight line edge of the second second resonator P12 are connected and have a second angle α2. Among them, the second straight line edge and the third straight line edge of the orthographic projection of the second second resonator P12 on the horizontal plane are closer to the first first resonator S11 and the third first resonator S13 than the first straight line edge of the orthographic projection of the second second resonator P12 on the horizontal plane.
[0075] Specifically, setting the first right-angled side of P12 around can better improve the area utilization rate of the bulk acoustic wave filter. The second straight line edge and the third straight line edge of the second second resonator P12 are connected and have a second angle α2 that depends on the area of P12.
[0076] In some embodiments, the second angle α2 formed by the second straight line edge and the third straight line edge of the second second resonator P12 is 140°-160°.
[0077] Specifically, the closer the second straight line edge of P12 is to being parallel to the tangent of the surface of S11 close to the second straight line edge, the greater the area utilization rate of the bulk acoustic wave filter. Similarly, the closer the third straight line edge of P12 is to being parallel to the tangent of the surface of S13 close to the third straight line edge, the greater the area utilization rate of the bulk acoustic wave filter. Therefore, when α2 is set to 140°-160°, the area utilization rate of the bulk acoustic wave filter is greater.
[0078] In some embodiments, the length d3 of the orthographic projection of the second second resonator screen 2 on the horizontal plane is equal to the second distance d2.
[0079] Specifically, d2 is equal to d3. The height of P12 depends on the area of P12. The smaller the area, the smaller the height, and the higher the area utilization rate of the layout.
[0080] In some embodiments, the area of the orthographic projection of the second first resonator S12 on the horizontal plane is equal to the area of the orthographic projection of the third first resonator S13 on the horizontal plane, and is less than the area of the orthographic projection of the first first resonator S11 on the horizontal plane; the area of the orthographic projection of the first first resonator S11 on the horizontal plane is less than the area of the orthographic projection of the third second resonator P13 on the horizontal plane; the area of the orthographic projection of the third second resonator P13 on the horizontal plane is less than the area of the orthographic projection of the first second resonator P11 on the horizontal plane; the area of the orthographic projection of the first second resonator P11 on the horizontal plane is less than the area of the orthographic projection of the second second resonator P12 on the horizontal plane.
[0081] In some embodiments, the area of S11 is between 5204.4 um 2 and 7269 um 2 ; the area of S12 is between 3484 um 2 and 5204.4 um 2 ; the area of S13 is between 3484 um 2 and 5204.4 um 2 ; the area of P11 is between 15527.3 um 2 and 18968.3 um 2 ; the area of P12 is between 18968.3 um 2 and 22753.3 um 2 ; the area of P13 is between 12430.4 um 2 and 15527.3 um 2 .
[0082] Figure 9 is Figure 6 and Figure 7 the S-parameter curve graph of the wide frequency band of the corresponding third-order bulk acoustic wave filter. Among them, L1 is Figure 6 the S-parameter curve of the wide frequency band of the corresponding bulk acoustic wave filter, and L2 is Figure 7 the S-parameter curve of the wide frequency band of the corresponding bulk acoustic wave filter. Figure 10 is Figure 6 and Figure 7 the S-parameter curve graph at the center frequency of the corresponding third-order bulk acoustic wave filter. Among them, N1 is Figure 6 the S-parameter curve at the center frequency of the corresponding bulk acoustic wave filter, and N2 is Figure 7 the S-parameter curve at the center frequency of the corresponding bulk acoustic wave filter. As Figures 9-10 shown, by Figure 6 and Figure 7The S-parameters of the corresponding third-order bulk acoustic wave filters were compared. It can be seen that the insertion loss of the bulk acoustic wave filter provided by the embodiments of the present disclosure has been improved, the overall performance of the filter has been enhanced, and the structure is more compact, improving the area utilization rate.
[0083] It should be noted that Figure 6 each first resonator S in the corresponding third-order bulk acoustic wave filter, and Figure 7 the areas of each first resonator S in the corresponding third-order bulk acoustic wave filter are the same. Similarly, Figure 6 each second resonator P in the corresponding third-order bulk acoustic wave filter, and Figure 7 the areas of each second resonator P in the corresponding third-order bulk acoustic wave filter are also the same. Since Figure 7 the layout structures of each first resonator S and second resonator P are different, resulting in different overall areas of the final third-order bulk acoustic wave filter. Therefore, the bulk acoustic wave filter provided by the embodiments of the present disclosure can greatly improve the area utilization rate of the bulk acoustic wave filter without affecting the performance, thereby realizing the small chip-on-chip design of the bulk acoustic wave filter.
[0084] It can be understood that the distances between the resonators (the first resonator S and the second resonator P, or between the first resonators S, or between the second resonators P) in the bulk acoustic wave filter provided by the embodiments of the present disclosure (for example Figure 7 ) may vary from those in the bulk acoustic wave filter in the prior art (for example Figure 6 ). Specifically, it needs to be determined according to the positions and areas of each resonator. However, the distances between each resonator are all greater than the first preset distance to ensure that there is no parasitic interference between each resonator, thereby ensuring that the performance of the bulk acoustic wave resonator will not be affected.
[0085] It should also be noted that in all the embodiments described by taking the third-order bulk acoustic wave filter as an example in the present disclosure, the structural layout of the bulk acoustic wave filter is carried out on the premise that the overall occupied area of the first resonator S and the second resonator P is the smallest area combination. When the area combination of the first resonator S and the second resonator P changes, the structural layout of the bulk acoustic wave filter may be appropriately adjusted.
[0086] In some embodiments, the orthographic projection of the bulk wave filter on the horizontal plane is a rectangle. Specifically, in order to save area as much as possible, the Figure 4 periphery is preferably set as a straight line instead of a curved shape.
[0087] In some embodiments, the first resonator S is a thin film bulk acoustic wave resonator or a solidly mounted resonator; the second resonator P is a thin film bulk acoustic wave resonator or a solidly mounted resonator.
[0088] Based on the same inventive concept, embodiments of the present disclosure further provide an electronic device, including the bulk acoustic wave filter described in any one of the above embodiments.
[0089] It can be understood that the above embodiments are merely exemplary embodiments adopted to illustrate the principles of the present invention. However, the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered within the protection scope of the present invention.
Claims
1. A bulk acoustic wave filter, characterized in that, Including N first resonators and N second resonators, the second electrode of the i-th first resonator is connected to the first electrode of the (i + 1)-th first resonator, where i ranges from 1 to (N - 1) and N ≥ 2; The first electrode of the j-th second resonator is connected to the second electrode of the j-th first resonator, and the second electrode of the j-th second resonator is connected to the reference potential terminal; j ranges from 1 to N; Wherein, the N second resonators are divided into two groups, and the N first resonators are located between the two groups of second resonators, and at least part of the centers of the orthographic projections of the first resonators on the horizontal plane are located on the same straight line.
2. The bulk acoustic wave filter according to claim 1, characterized in that, N = 3. The second electrode of the first first resonator is connected to the first electrode of the second first resonator, and the second electrode of the second first resonator is connected to the first electrode of the third first resonator; the first electrode of the first second resonator is connected to the second electrode of the first first resonator, the first electrode of the second second resonator is connected to the second electrode of the second first resonator, the first electrode of the third second resonator is connected to the second electrode of the third first resonator, and the second electrodes of the first second resonator, the second second resonator, and the third second resonator are all connected to the reference potential terminal; Wherein, the first second resonator and the third second resonator are used as the first group, the second second resonator is used as the second group, and the first first resonator, the second first resonator, and the third first resonator are located between the first group and the second group.
3. The bulk acoustic wave filter according to claim 2, characterized in that, The first second resonator, the third second resonator, the first first resonator, and the third first resonator define a first region, and the second first resonator is embedded in the first region.
4. The bulk acoustic wave filter according to claim 2, wherein The orthographic projections of the first second resonator and the third second resonator on the horizontal plane are both quarter-ellipses formed by an arc side and two straight sides; The orthographic projections of the first first resonator, the second first resonator, and the third first resonator on the horizontal plane are all semi-ellipses formed by an arc side and a straight side; The orthographic projection of the second second resonator on the horizontal plane is a closed shape formed by two relatively arranged arcs and three straight sides.
5. The bulk acoustic wave filter according to claim 4, characterized in that, For the first first resonator and the third first resonator, the connection line of the centers of their orthographic projections on the horizontal plane is the first straight line, and the maximum distance between their orthographic projections on the horizontal plane is the first distance; for the first first resonator and the third first resonator, the connection line of the centers of their orthographic projections on the horizontal plane is the second straight line, and the maximum distance between their orthographic projections on the horizontal plane is the second distance, where The first straight line is parallel to the second straight line, and the first distance is equal to the second distance.
6. The bulk acoustic wave filter according to claim 4, wherein The arc sides of the orthographic projections of the first second resonator and the third second resonator on the horizontal plane are adjacent to each other; The arc sides of the positive projections of the first first resonator and the third first resonator on the horizontal plane are adjacently arranged; The arc side of the positive projection of the second first resonator on the horizontal plane is adjacent to the arc side of the positive projection of the third second resonator on the horizontal plane.
7. The bulk acoustic wave filter according to claim 5, characterized in that, For the second first resonator and the first first resonator, the connecting line of the centers of their positive projections on the horizontal plane is the third straight line, and the third straight line has a first included angle with the second straight line.
8. The bulk acoustic wave filter according to claim 7, wherein The first included angle is 10° - 35°.
9. The bulk acoustic wave filter according to claim 5, wherein The two arc sides of the positive projection of the second second resonator on the horizontal plane are arranged oppositely along the direction of the second straight line. The two ends of the first straight line side of the positive projection of the second second resonator on the horizontal plane are respectively connected to the two arc sides. The second straight line side and the third straight line side of the second second resonator are connected and have a second included angle. Among them, The second straight line side and the third straight line side of the positive projection of the second second resonator on the horizontal plane are closer to the first first resonator and the third first resonator than the first straight line side of the positive projection of the second second resonator on the horizontal plane.
10. The bulk acoustic wave filter according to claim 9, characterized in that, The second included angle formed by the second straight line side and the third straight line side of the second second resonator is 140° - 160°.
11. The bulk acoustic wave filter according to claim 10, characterized in that, The length of the positive projection of the second second resonator on the horizontal plane is equal to the second distance.
12. The bulk acoustic wave filter according to claim 2, wherein The area of the positive projection of the second first resonator on the horizontal plane is equal to the area of the positive projection of the third first resonator on the horizontal plane, and is smaller than the area of the positive projection of the first first resonator on the horizontal plane; the area of the positive projection of the first first resonator on the horizontal plane is smaller than the area of the positive projection of the third second resonator on the horizontal plane; The area of the positive projection of the third second resonator on the horizontal plane is smaller than the area of the positive projection of the first second resonator on the horizontal plane; the area of the positive projection of the first second resonator on the horizontal plane is smaller than the area of the positive projection of the second second resonator on the horizontal plane.
13. The bulk acoustic wave filter according to claim 1, characterized in that, The positive projection of the bulk acoustic wave filter on the horizontal plane is rectangular.
14. The bulk acoustic wave filter according to claim 1, wherein The first resonator is a thin film bulk acoustic wave resonator or a solidly mounted resonator; The second resonator is a thin film bulk acoustic wave resonator or a solidly mounted resonator.
15. An electronic device, characterized in that, Comprising the bulk acoustic wave filter according to any one of claims 1 - 14.