Filter and electronic device
By adjusting the transducer duty cycle in the longitudinally coupled resonant filter, the problem that the surface acoustic wave filter is susceptible to the Ruili mode is solved, achieving better out-of-band rejection and overall performance.
Patent Information
- Application Number
- CN202510058672.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-14
- Publication Date
- 2025-05-13
AI Technical Summary
Surface acoustic wave filters are susceptible to unwanted clutter modes such as Ruili mode, resulting in deterioration of out-of-band suppression performance.
By adjusting and optimizing the duty cycles of multiple transducers of the longitudinally coupled resonant filter to make them different, thereby reducing the excitation intensity of the Ruili mode and the near-end high-frequency clutter mode.
Effectively suppress the Ruili mode and the near-end high-frequency clutter mode of the filter, improve the overall performance of the filter, and reduce process complexity and production costs.
Smart Images
Figure CN119995556A_ABST
Abstract
Description
Technical Field
[0001] The present application belongs to the field of semiconductor technology, and in particular, relates to a filter and an electronic device. Background Art
[0002] Surface acoustic wave (SAW) filters are widely used in mobile communications due to their good frequency selectivity, low cost and consistency. In modern mobile communication systems, the number of frequency bands continues to increase, the electromagnetic environment becomes more complex, and the requirements for the ability of each communication system to resist interference are also increasing. Therefore, the requirements for surface acoustic wave filters are also very high. However, surface acoustic wave filters are easily affected by unwanted clutter modes such as the Rayleigh mode, resulting in deterioration of the filter's out-of-band suppression performance. Summary of the invention
[0003] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a filter and an electronic device, which can suppress the Rayleigh mode and the near-end high-frequency clutter mode of the filter and improve the overall performance of the filter.
[0004] In a first aspect, the present application provides a filter, comprising a plurality of filter elements connected in series and / or in parallel, each of the filter elements comprising a transducer, the plurality of filter elements comprising at least one longitudinally coupled resonant filter, the longitudinally coupled resonant filter comprising a plurality of the transducers;
[0005] The duty cycles of the plurality of transducers of the longitudinally coupled resonant filter are different.
[0006] According to the filter of the present application, by adjusting and optimizing the duty cycles of multiple transducers of the longitudinal coupling resonant filter, the duty cycles of the multiple transducers of the longitudinal coupling resonant filter are made different, thereby reducing the excitation intensity of the Rayleigh mode and the near-end high-frequency clutter mode of the longitudinal coupling resonant filter, thereby suppressing the Rayleigh mode and the near-end high-frequency clutter mode of the filter and improving the overall performance of the filter.
[0007] According to one embodiment of the present application, the plurality of transducers of the longitudinally coupled resonant filter are sequentially distributed along the target direction;
[0008] The duty ratios of the plurality of transducers of the longitudinally coupled resonant filter are sequentially increased, sequentially decreased, alternately distributed in size, or randomly distributed in size along the target direction.
[0009] According to an embodiment of the present application, the duty cycles of the transducers of the plurality of filter elements are different.
[0010] According to one embodiment of the present application, the plurality of filter elements further include at least one surface acoustic wave resonator;
[0011] The duty cycle of the transducer of the surface acoustic wave resonator is different from the duty cycle of the transducer of the longitudinally coupled resonator filter.
[0012] According to one embodiment of the present application, a duty cycle of the transducer of the longitudinally coupled resonant filter is smaller than a duty cycle of the transducer of the surface acoustic wave resonator.
[0013] According to one embodiment of the present application, the plurality of filter elements include a plurality of the surface acoustic wave resonators;
[0014] The duty ratios of the transducers of the plurality of surface acoustic wave resonators are different.
[0015] According to one embodiment of the present application, the duty cycle of the transducer of the surface acoustic wave resonator is 0.3-0.7.
[0016] According to one embodiment of the present application, the filter further includes an input end and an output end, and the plurality of filter elements are connected between the input end and the output end;
[0017] The duty cycle of the transducer of the filter element connected in series with the input terminal is different from the duty cycles of the transducers of the other filter elements.
[0018] According to one embodiment of the present application, the duty cycle of the transducer of the longitudinally coupled resonant filter is 0.3-0.65.
[0019] In a second aspect, the present application provides an electronic device, comprising the filter as described in the first aspect above.
[0020] The above one or more technical solutions in the embodiments of the present application have at least one of the following technical effects:
[0021] By adjusting and optimizing the duty ratios of multiple transducers of the longitudinal coupling resonant filter, the duty ratios of the multiple transducers of the longitudinal coupling resonant filter are made different, and the excitation intensity of the Rayleigh mode and the near-end high-frequency clutter mode of the longitudinal coupling resonant filter is reduced, thereby suppressing the Rayleigh mode and the near-end high-frequency clutter mode of the filter and improving the overall performance of the filter.
[0022] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:
[0024] Figure 1 is a schematic diagram of the structure of the filter provided in an embodiment of the present application;
[0025] Figure 2 It is one of the structural schematic diagrams of the filter element in the filter provided in the embodiment of the present application;
[0026] Figure 3 This is the second structural schematic diagram of the filter element in the filter provided in the embodiment of the present application;
[0027] Figure 4 It is one of the cross-sectional schematic diagrams of the filter element in the filter provided in the embodiment of the present application;
[0028] Figure 5 This is the second cross-sectional schematic diagram of the filter element in the filter provided in the embodiment of the present application;
[0029] Figure 6 This is the third structural schematic diagram of the filter element in the filter provided in the embodiment of the present application;
[0030] Figure 7 It is a schematic diagram of the relationship between the frequency and the amplitude value of the admittance curve when the duty cycle of the transducer of the filter element in the filter provided in the embodiment of the present application is different;
[0031] Figure 8 is a schematic diagram of the relationship between the frequency and the real part of the admittance curve when the duty cycle of the transducer of the filter element in the filter provided in the embodiment of the present application is different;
[0032] Fig. 9 is a frequency response comparison diagram of the longitudinally coupled resonant filter provided in the embodiment of the present application when the duty ratios of the transducers are the same and different;
[0033] Fig.10 It is a comparison diagram of the frequency responses of filters in the embodiments of the present application and in the related art. DETAILED DESCRIPTION
[0034] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.
[0035] The filter and electronic device provided by the embodiments of the present application are described below with reference to the accompanying drawings.
[0036] Figure 1 The schematic diagram of the structure of the filter provided in the embodiment of the present application is shown in FIG.
[0037] like Figure 1As shown, the filter includes multiple filter elements connected in series and / or in parallel, that is, multiple filter elements are connected in series, or multiple filter elements are connected in parallel, or some filter elements are connected in series and then connected in parallel with another part of the filter elements. The multiple filter elements include at least one longitudinal coupling resonant filter 12. Among them, the filter may only include the longitudinal coupling resonant filter 12, and does not include other types of filter elements, that is, the multiple filter elements may all be longitudinal coupling resonant filters 12. The filter may also include the longitudinal coupling resonant filter 12 and other types of filter elements, that is, some of the filter elements among the multiple filter elements are longitudinal coupling resonant filters 12, and the other part of the filter elements are other types of filter elements (such as surface acoustic wave resonators).
[0038] like Figure 2 and Figure 3 As shown, each filter element includes a transducer 13, and the transducer 13 may be an interdigital transducer IDT. Figure 2 As shown, the longitudinal coupling resonant filter 12 may include a plurality of transducers 13 sequentially distributed along the target direction X. The filter element further includes a reflection strip 19, such as the plurality of transducers 13 of the longitudinal coupling resonant filter 12 are provided with reflection strips 19 on opposite sides along the target direction X, respectively.
[0039] In some embodiments, Figure 2 and Figure 3 As shown, the transducer 13 includes a plurality of electrode fingers, a first busbar 23 and a second busbar 24. The plurality of electrode fingers include first electrode fingers 21 and second electrode fingers 22 that are alternately and spaced apart along the target direction X. The first busbar 23 and the second busbar 24 are spaced apart along the first direction Y, the first direction Y is perpendicular to the target direction X, and the first electrode fingers 21 and the second electrode fingers 22 are located between the first busbar 23 and the second busbar 24. The first electrode finger 21 extends to the first busbar 23 along the first direction Y and is connected to the first busbar 23. The second electrode finger 22 extends to the second busbar 24 along the first direction Y and is connected to the second busbar 24. Among them, the sizes (including length and width, etc.) of the first electrode finger 21 and the second electrode finger 22 may be the same. The materials of the first electrode finger 21, the second electrode finger 22, the first busbar 33 and the second busbar 34 may include metal materials such as copper and aluminum, respectively.
[0040] In some embodiments, Figure 4 and Figure 5 As shown, the filter element includes a piezoelectric layer 14, and the transducer 13 is located on one side of the second direction Z of the piezoelectric layer 14, the second direction Z is the thickness direction of the piezoelectric layer 14, and the second direction Z is respectively perpendicular to the target direction X and the first direction Y. The piezoelectric layer 14 may include materials such as LT and LN.
[0041] It should be noted that the filter element may be a POI structure. Figure 4 As shown, the filter element may further include a substrate 16 and a support layer 15, wherein the support layer 15 is located on the side of the piezoelectric layer 14 away from the transducer 13, and the substrate 16 is located on the side of the support layer 15 away from the piezoelectric layer 14. The support layer 15 may include silicon oxide, etc. The substrate 16 may include silicon, etc. The filter element may also be other types of structures. Figure 5 As shown, the filter element may further include a first covering layer 17 and a second covering layer 18, wherein the first covering layer 17 covers the transducer 13 and the piezoelectric layer 14, and the second covering layer 18 is located on a side of the first covering layer 17 away from the piezoelectric layer 14. The first covering layer 17 includes silicon oxide and the like, and the second covering layer 18 includes silicon nitride and the like.
[0042] The duty cycles of the multiple (two or more) transducers 13 of the longitudinal coupling resonant filter 12 are different, that is, the duty cycles of at least two transducers 13 of the longitudinal coupling resonant filter 12 are different. The duty cycle MR of the transducer 13 is the ratio of the width a of the electrode finger to the repetition period p of the electrode finger (that is, half the wavelength), that is, MR=a / p.
[0043] In some embodiments, the duty cycles of the transducers 13 of the longitudinally coupled resonant filter 12 are different. Figure 6 As shown, the longitudinally coupled resonant filter 12 includes five transducers 13a, 13b, 13c, 13d and 13e. The duty ratios of the five transducers 13a, 13b, 13c, 13d and 13e are different.
[0044] The filter is easily affected by unwanted clutter modes such as the Rayleigh mode, resulting in deterioration of the filter's out-of-band suppression performance. In order to suppress the Rayleigh mode, the duty cycle of each transducer in the longitudinally coupled resonant filter in the filter in the related art is the same, and the coupling coefficient is reduced by changing the cut or thickness of the piezoelectric layer to reduce the excitation of the Rayleigh mode. However, this method requires customization of wafers with specific cuts or specific thicknesses, which is complex in process and has high production costs.
[0045] The intensity of the Rayleigh mode is related to the number of electrode fingers in the filter element. The total number of electrode fingers in the longitudinal coupling resonant filter 12 is relatively large, and is the main source of the Rayleigh mode. This embodiment adjusts and optimizes the duty cycle of the multiple transducers 13 of the longitudinal coupling resonant filter 12 so that the duty cycles of the multiple transducers 13 of the longitudinal coupling resonant filter 12 are different, thereby reducing the excitation intensity of the Rayleigh mode and, to a certain extent, reducing the excitation intensity of other high-frequency noise modes, thereby effectively improving the out-of-band suppression effect. Moreover, by simply adjusting the duty cycle of the multiple transducers 13 of the longitudinal coupling resonant filter 12, the Rayleigh mode and the proximal high-frequency noise mode of the filter can be suppressed, without the need to adopt complex wafer back side processing technology, reducing process complexity, and reducing production costs.
[0046] In some embodiments, the multiple transducers 13 of the longitudinal coupling resonant filter 12 are sequentially distributed along the target direction X. The duty ratios of the multiple transducers 13 of the longitudinal coupling resonant filter 12 are sequentially increased, decreased, alternately distributed, or randomly distributed along the target direction X.
[0047] For example, the longitudinal coupling resonant filter 12 includes five transducers 13a, 13b, 13c, 13d and 13e distributed in sequence along the target direction X. The duty ratios of the five transducers 13a, 13b, 13c, 13d and 13e can be increased in sequence, with the duty ratio of the transducer 13a being the largest and the duty ratio of the transducer 13e being the smallest. Alternatively, the duty ratios of the five transducers 13a, 13b, 13c, 13d and 13e can also be decreased in sequence, with the duty ratio of the transducer 13a being the smallest and the duty ratio of the transducer 13e being the largest. Alternatively, the duty ratios of the five transducers 13a, 13b, 13c, 13d, and 13e may be distributed alternately in size, the duty ratio of transducer 13b is greater than the duty ratio of transducer 13a, the duty ratio of transducer 13c is less than the duty ratio of transducer 13b, the duty ratio of transducer 13d is greater than the duty ratio of transducer 13c, and the duty ratio of transducer 13e is less than the duty ratio of transducer 13d. Alternatively, the duty ratios of the five transducers 13a, 13b, 13c, 13d, and 13e are randomly distributed, that is, the size relationship of the duty ratios of the five transducers 13a, 13b, 13c, 13d, and 13e is not specifically limited.
[0048] In some embodiments, the duty cycles of the transducers 13 of multiple (two or more) filter elements are different, that is, the duty cycles of the transducers 13 of at least two of the multiple filter elements are different. For example, the duty cycles of the transducers 13 of at least two longitudinally coupled resonant filters 12 of the multiple filter elements are different. Alternatively, the multiple filter elements also include other types of filter elements (such as surface acoustic wave resonators) different from the longitudinally coupled resonant filters 12, and the duty cycles of at least one longitudinally coupled resonant filter 12 of the multiple filter elements and the transducer 13 of at least one other type of filter element are different, or the duty cycles of the transducers 13 of at least two other types of filter elements of the multiple filter elements are different. In some embodiments, the duty cycles of the transducers 13 of each filter element are different.
[0049] The excitation of the Rayleigh mode is related to the duty cycle of the transducer 13 of the filter element. In this embodiment, the duty cycle of the transducers of multiple filter elements is adjusted and optimized to suppress the Rayleigh mode. Figure 7 and Figure 8 The simulation analysis is conducted on the Rayleigh mode excited on the filter element (such as a surface acoustic wave resonator) when the duty cycle of the transducer of the filter element is 0.4, 0.5 and 0.6 respectively. Figure 7 It is a schematic diagram of the relationship between the amplitude value and frequency of the admittance curve of the transducer of the filter element at different duty cycles. Figure 8 The figure is a schematic diagram showing the relationship between the real part of the admittance curve and the frequency of the transducer of the filter element at different duty cycles. Figure 7 and Figure 8 It can be seen that the different duty cycles of the transducers make the 1.5GHz Rayleigh mode more dispersed. Therefore, the duty cycles of the transducers 13 of the multiple filter elements in the filter are different, which disperses the Rayleigh mode and the near-end high-frequency noise mode generated by the multiple filter elements, so that the Rayleigh mode and the near-end high-frequency noise mode generated by the multiple filter elements can be evenly distributed within a certain frequency range, avoiding the superposition of the Rayleigh mode and the near-end high-frequency noise mode generated by the multiple filter elements to form a strong parasitic peak, thereby suppressing the Rayleigh mode and the near-end high-frequency noise mode of the filter and improving the overall performance of the filter. Moreover, by simply adjusting the duty cycle of the transducers 13 of the multiple filter elements, the Rayleigh mode and the near-end high-frequency noise mode of the filter can be suppressed, without the need to adopt complex wafer backside processing technology, reducing process complexity, and reducing production costs.
[0050] In some embodiments, the duty cycle of the transducer 13 of each filtering element is 0.3-0.7.
[0051] In this embodiment, the duty cycle of the transducers 13 of the plurality of filter elements is adjusted within the range of 0.3-0.7 to suppress the Rayleigh mode and the near-end high-frequency clutter mode of the filter while avoiding affecting the main mode of the filter element.
[0052] In some embodiments, the period lengths of the transducers 13 of the multiple filter elements are the same, and the widths of the electrode fingers of the transducers 13 of the multiple filter elements are different, so that the duty cycles of the transducers 13 of the multiple filter elements are different.
[0053] The period length p of the transducer 13 remains unchanged, and the duty cycle MR of the transducer 13 can be adjusted by adjusting the width a of the electrode finger of the transducer 13. Increasing the width a of each electrode finger of the transducer 13 can increase the duty cycle MR of the transducer 13; reducing the width a of each electrode finger of the transducer 13 can reduce the duty cycle MR of the transducer 13. It should be noted that the width a of each electrode finger in the same transducer 13 increases or decreases at the same time, that is, the width a of each electrode finger in the same transducer 13 remains consistent.
[0054] like Figure 6As shown, the longitudinal coupling resonant filter 12 includes five transducers 13a, 13b, 13c, 13d and 13e. The period lengths of the electrode fingers of the five transducers 13a, 13b, 13c, 13d and 13e are the same, but the widths of the electrode fingers of the five transducers 13a, 13b, 13c, 13d and 13e are different, so that the duty ratios of the five transducers 13a, 13b, 13c, 13d and 13e are different.
[0055] In some embodiments, the plurality of filter elements further include at least one surface acoustic wave resonator 11, that is, the plurality of filter elements include at least one surface acoustic wave resonator 11 and at least one longitudinal coupling resonant filter 12. The number of the surface acoustic wave resonator 11 and the longitudinal coupling resonant filter 12 is not specifically limited. The number of the surface acoustic wave resonator 11 and the longitudinal coupling resonant filter 12 may be the same or different.
[0056] like Figure 3 As shown, the surface acoustic wave resonator 11 may include a transducer 13. The transducer 13 of the surface acoustic wave resonator 11 is provided with reflection strips 19 on opposite sides along the target direction X, respectively.
[0057] The duty ratios of the surface acoustic wave resonator 11 and the transducer 13 of the longitudinal coupling resonator filter 12 are different, that is, the duty ratios of at least one surface acoustic wave resonator 11 and at least one transducer 13 of the longitudinal coupling resonator filter 12 in the plurality of filter elements are different.
[0058] In some embodiments, the duty cycle of the transducer 13 of the longitudinal coupling resonator filter 12 is smaller than the duty cycle of the transducer 13 of the surface acoustic wave resonator 11. The longitudinal coupling resonator filter 12 includes a plurality of transducers 13, and the duty cycle of each transducer 13 of the longitudinal coupling resonator filter 12 is smaller than the duty cycle of the transducer 13 of the surface acoustic wave resonator 11.
[0059] When the number of electrode fingers of the transducer 13 of the surface acoustic wave resonator 11 is small, a large part of the Rayleigh mode in the filter frequency response comes from the longitudinal coupling resonant filter 12. The duty cycle of the transducer 13 of the longitudinal coupling resonant filter 12 is smaller than the duty cycle of the transducer 13 of the surface acoustic wave resonator 11, which can reduce the excitation intensity of the Rayleigh mode and reduce the excitation intensity of other proximal high-frequency clutter modes to a certain extent, thereby effectively improving the out-of-band suppression effect.
[0060] In some embodiments, the duty cycle of the transducer 13 of the longitudinal coupling resonant filter 12 can be 0.3-0.65, and the duty cycle of the transducer 13 of the surface acoustic wave resonator 11 can be 0.3-0.7, so that the duty cycle of the transducer 13 of the longitudinal coupling resonant filter 12 is smaller than the duty cycle of the transducer 13 of the surface acoustic wave resonator 11.
[0061] Fig. 9 FIG. 1 is a frequency response comparison diagram when the duty ratios of the transducers 13 of the longitudinal coupling resonant filter 12 are the same and different. Fig. 9 It can be seen that when the duty ratios of the transducers 13 of the longitudinal coupling resonant filter 12 are the same, the Rayleigh mode and the near-end high-frequency clutter mode will be generated. When the duty ratios of the transducers 13 of the longitudinal coupling resonant filter 12 are different, and the duty ratios of the transducers 13 of the longitudinal coupling resonant filter 12 are slightly smaller than the duty ratios of the transducers 13 of the surface acoustic wave resonator 11, the frequency response is smoother, the Rayleigh mode is almost completely suppressed, and the near-end high-frequency clutter mode is also suppressed.
[0062] In some embodiments, the plurality of filter elements include a plurality of surface acoustic wave resonators 11, and the duty ratios of the transducers 13 of the plurality of (two or more) surface acoustic wave resonators 11 are different, that is, the duty ratios of the transducers 13 of at least two surface acoustic wave resonators 11 in the filter are different. In some embodiments, the duty ratios of the transducers 13 of the surface acoustic wave resonators 11 in the filter are all different.
[0063] In this embodiment, the duty cycles of the multiple surface acoustic wave resonators 11 are different, which can disperse the Rayleigh mode and the near-end high-frequency clutter mode generated by the multiple surface acoustic wave resonators 11, avoid the superposition of the Rayleigh mode and the near-end high-frequency clutter mode generated by the multiple surface acoustic wave resonators 11, thereby suppressing the Rayleigh mode and the near-end high-frequency clutter mode of the filter and improving the overall performance of the filter.
[0064] For example, the band25 filter includes five surface acoustic wave resonators 11 connected in series and parallel and a longitudinal coupling resonant filter 12. In the related art, the duty ratios of the transducers of the five surface acoustic wave resonators and the one longitudinal coupling resonant filter of the filter are the same, and the duty ratios of the transducers of the longitudinal coupling resonant filter are the same. In this embodiment, the duty ratios of the transducers 13 of the five surface acoustic wave resonators 11 are different, and the duty ratio of the transducer 13 of each surface acoustic wave resonator 11 is about 0.6, and the duty ratios of the transducers 13 of the longitudinal coupling resonant filter 12 are different, and the duty ratio of each transducer 13 of the longitudinal coupling resonant filter 12 is about 0.45.
[0065] Fig.10 : is a frequency response comparison diagram of the filter in this embodiment and the related art. Fig.10It can be seen that the filter in the related art has obvious Rayleigh mode and high-frequency clutter peaks at 1.5GHz and 2.2GHz, which seriously affect the out-of-band suppression performance of the filter. However, this embodiment significantly reduces the clutter intensity at 1.5GHz and 2.2GHz by adjusting the duty cycle of the transducers of each surface acoustic resonator and the duty cycle of each transducer of the longitudinal coupling resonant filter, and the overall performance is a smoother frequency response curve, and the out-of-band suppression effect is significantly improved.
[0066] It should be noted that the adjustment of the duty cycle of the transducer will lead to the distortion of the filter passband frequency response, especially the deterioration of the high-end performance of the passband at 2.0GHz-2.02GHz. However, the performance of the low-end of the passband can be optimized by adjusting the repetition period p of the electrode fingers of the longitudinally coupled resonant filter and the surface acoustic wave resonator.
[0067] In some embodiments, Figure 1 As shown, the filter also includes an input terminal In and an output terminal Out, and a plurality of filter elements are connected between the input terminal In and the output terminal Out. The plurality of filter elements can be connected in series between the input terminal In and the output terminal Out; or, the plurality of filter elements are first connected in series and then in parallel between the input terminal In and the output terminal Out; or, the plurality of filter elements are first connected in parallel and then in series between the input terminal In and the output terminal Out. The duty cycle of the transducer 13 of the filter element connected in series with the input terminal In is different from the duty cycle of the transducer 13 of other filter elements. Among them, the filter element connected in series with the input terminal In may refer to the first filter element connected in series with the input terminal In, and the filter element connected in series with the input terminal In may be a surface acoustic wave resonator, a longitudinally coupled resonant filter, or other types of filter elements.
[0068] For example Figure 1 As shown, the filter element connected in series with the input terminal In is a surface acoustic wave resonator 11a, and the duty cycle of the transducer 13 of the surface acoustic wave resonator 11a is different from the duty cycle of the transducer 13 of the longitudinal coupling resonator filter 12 (and other surface acoustic wave resonators 11). The duty cycle of the transducer 13 of the longitudinal coupling resonator filter 12 (and other surface acoustic wave resonators 11) can be the same or different.
[0069] For another example, the filter element connected in series with the input terminal In is a longitudinal coupling resonant filter 12, and the duty cycle of the transducer 13 of the longitudinal coupling resonant filter 12 is different from the duty cycle of the transducer 13 of other filter elements (such as the surface acoustic wave resonator 11 and / or other longitudinal coupling resonant filters 12). The duty cycle of the transducer 13 of the longitudinal coupling resonant filter 12 may be slightly lower than the duty cycle of the transducer 13 of the surface acoustic wave resonator 11. The duty cycles of the transducers 13 of the longitudinal coupling resonant filter 12 are different. The duty cycles of the transducers 13 of other filter elements (such as the surface acoustic wave resonator 11 and / or other longitudinal coupling resonant filters 12) may be the same or different.
[0070] This embodiment adjusts the duty cycle of the transducer 13 of the filter element connected in series with the input terminal In to be different from the duty cycle of the transducer 13 of other filter elements, so as to disperse the Rayleigh mode and near-end high-frequency clutter mode generated by the filter element connected in series with the input terminal In and other filter elements, and effectively suppress the Rayleigh mode and near-end high-frequency clutter mode of the filter.
[0071] According to the filter provided in the embodiment of the present application, by adjusting and optimizing the duty cycles of the multiple transducers of the longitudinal coupling resonant filter 12, the duty cycles of the multiple transducers 13 of the longitudinal coupling resonant filter 12 are made different, thereby reducing the excitation intensity of the Rayleigh mode and the near-end high-frequency clutter mode of the longitudinal coupling resonant filter 12, thereby suppressing the Rayleigh mode and the near-end high-frequency clutter mode of the filter and improving the overall performance of the filter.
[0072] Correspondingly, an embodiment of the present application further provides an electronic device, including the filter in the above embodiment, which will not be described in detail here.
[0073] According to the electronic device provided in the embodiment of the present application, the duty cycles of the multiple transducers of the longitudinal coupling resonant filter are adjusted and optimized so that the duty cycles of the multiple transducers of the longitudinal coupling resonant filter are different, thereby reducing the excitation intensity of the Rayleigh mode and the near-end high-frequency clutter mode of the longitudinal coupling resonant filter, thereby suppressing the Rayleigh mode and the near-end high-frequency clutter mode of the filter, improving the overall performance of the filter, and further improving the performance of the electronic device.
[0074] The terms "first", "second", etc. in the specification and claims of this application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are generally of the same type, and the number of objects is not limited. For example, the first object can be one or more.
[0075] In the description of the present application, “plurality” means two or more.
[0076] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.
[0077] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.
Claims
1. A filter, characterized in that: The method comprises a plurality of filter elements connected in series and / or in parallel, each of the filter elements comprising a transducer, the plurality of filter elements comprising at least one longitudinally coupled resonant filter, and the longitudinally coupled resonant filter comprising a plurality of the transducers; The duty cycles of the plurality of transducers of the longitudinally coupled resonant filter are different.
2. The filter according to claim 1, characterized in that The plurality of transducers of the longitudinally coupled resonant filter are sequentially distributed along a target direction; The duty ratios of the plurality of transducers of the longitudinally coupled resonant filter are sequentially increased, sequentially decreased, alternately distributed in size, or randomly distributed in size along the target direction.
3. The filter according to claim 1, characterized in that The duty cycles of the transducers of the plurality of filter elements are different.
4. The filter according to claim 3, characterized in that The plurality of filter elements further include at least one surface acoustic wave resonator; The duty cycle of the transducer of the surface acoustic wave resonator is different from the duty cycle of the transducer of the longitudinally coupled resonator filter.
5. The filter according to claim 4, characterized in that The duty cycle of the transducer of the longitudinally coupled resonator filter is smaller than the duty cycle of the transducer of the surface acoustic wave resonator.
6. The filter according to claim 3, characterized in that The plurality of filter elements include a plurality of surface acoustic wave resonators; The duty ratios of the transducers of the plurality of surface acoustic wave resonators are different.
7. The filter according to any one of claims 4 to 6, characterized in that: The duty cycle of the transducer of the surface acoustic wave resonator is 0.3-0.
7.
8. The filter according to claim 1, characterized in that The filter further comprises an input end and an output end, and the plurality of filter elements are connected between the input end and the output end; The duty cycle of the transducer of the filter element connected in series with the input terminal is different from the duty cycles of the transducers of the other filter elements.
9. The filter according to claim 1, characterized in that The duty cycle of the transducer of the longitudinally coupled resonant filter is 0.3-0.
65.
10. An electronic device, characterized in that: Comprising the filter as claimed in any one of claims 1 to 9.