Surface acoustic wave filter and electronic device
By dividing the finger strip region in the capacitor structure and adjusting the finger strip parameters, a non-uniform interdigitated transducer finger strip structure is formed, which excites surface acoustic waves with different phases to cancel each other out, thus solving the problem of capacitor unit excitation of clutter and ensuring the passband and out-of-band performance of the filter.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-14
- Publication Date
- 2026-04-14
AI Technical Summary
When the surface acoustic wave signal excited by the capacitor unit is too strong, the existing surface acoustic wave filter is prone to generating high noise signals in the passband or out-of-band of the filter, which affects the out-of-band suppression characteristics of the filter.
The capacitor structure is divided into a first finger bar region and a second finger bar region, so that the finger bar parameters of the two finger bar regions are different, forming a non-uniform interdigitated transducer finger bar structure. The surface acoustic waves with different phases are excited and cancel each other out, reducing the excitation of clutter.
It effectively reduces the excitation intensity of clutter, ensuring the passband and out-of-band performance of the filter. Even if the rotation inside the piezoelectric substrate changes the orientation of the finger strips, it does not worsen the out-of-band suppression characteristics of the filter.
Smart Images
Figure CN121864052A_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of filter technology, and in particular relates to a surface acoustic wave filter and electronic device. Background Technology
[0002] With the development of mobile communication technology, the number of communication frequency bands has increased dramatically, from 4 bands in 2G to over 50 bands in 5G. Surface acoustic wave (SAW) filters are widely used in wireless communication terminals. To achieve miniaturization and high performance in matched filters, matching components such as capacitors and inductors are typically designed onto the filter chip. Simultaneously, one or more capacitors or inductors are connected in parallel to the resonator units on the filter, which perform signal processing tasks such as frequency selection and signal coupling, to improve the filter's rectangularity.
[0003] By utilizing the capacitive characteristics of interdigital transducers (IDTs), a capacitor unit with a finger-strip structure is fabricated. This capacitor element is then integrated onto a filter chip, allowing for flexible design of the capacitor unit's capacitance value and facilitating integration with a resonator unit (which also has an IDT finger-strip structure). However, when the surface acoustic wave signal excited by the capacitor unit is too strong, it can generate high levels of clutter in the filter's passband or out-of-band.
[0004] Currently, the finger placement direction of the capacitor unit is usually perpendicular to the finger placement direction of the resonator unit to reduce the surface acoustic wave signal excited by the capacitor unit. However, when the finger placement direction is changed by rotating the piezoelectric substrate in the filter, the noise excited by the capacitor unit is stronger, which may deteriorate the out-of-band rejection characteristics of the filter. Summary of the Invention
[0005] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes a surface acoustic wave filter and electronic device that can reduce clutter excitation and ensure the passband and out-of-band performance of the filter.
[0006] In a first aspect, this application provides a surface acoustic wave filter, comprising:
[0007] A resonator structure having a first finger extending along a first direction;
[0008] A capacitor structure is connected in parallel with the resonator structure. The capacitor structure includes two busbars arranged opposite to each other. Between the two busbars is a target finger bar that is connected to one of the busbars and spaced apart from the other busbar. The target finger bar extends along a second direction. The capacitor structure is divided into alternating first finger bar regions and second finger bar regions along the length direction of the busbars.
[0009] The target finger bar in the first finger bar area is the first target finger bar, and the target finger bar in the second finger bar area is the second target finger bar. The finger bar parameters of the first target finger bar and the second target finger bar are different.
[0010] According to the surface acoustic wave filter of this application, by dividing the capacitor structure into a first finger bar region and a second finger bar region, the finger bar parameters of the two finger bar regions are different, so that the capacitor structure forms a non-uniform interdigitated transducer finger bar structure, and the surface acoustic waves with different phases are excited and cancel each other out, which can reduce the excitation of clutter. Even if the finger bar placement direction is changed by rotating within the piezoelectric substrate, the out-of-band suppression characteristics of the filter will not be deteriorated, thus ensuring the passband and out-of-band performance of the filter.
[0011] According to one embodiment of this application, the finger bar parameters include at least one of the finger bar width and the finger bar connection busbar position.
[0012] According to one embodiment of this application, the second finger strip region has at least one second target finger strip, the width of the second target finger strip being greater than the width of the first target finger strip.
[0013] According to one embodiment of this application, the width of the second target finger strip is 1.5 to 4.5 times the width of the first target finger strip.
[0014] According to one embodiment of this application, the second finger strip region has at least two second target finger strips, and the at least two second target finger strips are connected to the same busbar within the second finger strip region.
[0015] According to one embodiment of this application, the second finger strip region has at least two second target finger strips, and the at least two second target finger strips are connected to the same busbar within the second finger strip region;
[0016] Within the first finger strip area, two adjacent first target finger strips are connected to different busbars.
[0017] According to one embodiment of this application, the first target finger strips are evenly arranged within the first finger strip area.
[0018] According to one embodiment of this application, the angle between the resonator interdigitation direction and the capacitor interdigitation direction of the surface acoustic wave filter is 0°-90°, the resonator interdigitation direction is the first direction, and the capacitor interdigitation direction is the second direction.
[0019] According to one embodiment of this application, the width of the first target finger strip is the same as the width of the first finger strip.
[0020] According to one embodiment of this application, the width of the first target finger strip is different from the width of the first finger strip.
[0021] According to one embodiment of this application, the resonator structure includes a surface acoustic wave resonator or a longitudinally coupled resonator.
[0022] Secondly, this application provides an electronic device comprising:
[0023] The surface acoustic wave filter as described in the first aspect above.
[0024] According to the electronic device of this application, by dividing the capacitor structure into a first finger strip region and a second finger strip region, the finger strip parameters of the two finger strip regions are different, so that the capacitor structure forms a non-uniform interdigitated transducer finger strip structure, and the surface acoustic waves with different phases are excited and cancel each other out, which can reduce the excitation of clutter. Even if the piezoelectric substrate is rotated to change the placement direction of the finger strips, the out-of-band suppression characteristics of the filter will not be deteriorated, thus ensuring the passband and out-of-band performance of the filter.
[0025] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description
[0026] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:
[0027] Figure 1 This is a schematic diagram of the structure of the surface acoustic wave filter provided in the embodiments of this application;
[0028] Figure 2 This is one of the schematic diagrams of the capacitor structure of the surface acoustic wave filter provided in the embodiments of this application;
[0029] Figure 3 This is a second schematic diagram of the capacitor structure of the surface acoustic wave filter provided in the embodiments of this application;
[0030] Figure 4 This is the third schematic diagram of the capacitor structure of the surface acoustic wave filter provided in the embodiments of this application;
[0031] Figure 5 This is a schematic diagram of the surface acoustic wave resonator of the surface acoustic wave filter provided in the embodiments of this application;
[0032] Figure 6 This is a schematic diagram of the longitudinal coupling resonator of the surface acoustic wave filter provided in this application embodiment;
[0033] Figure 7This is one of the schematic diagrams of filter admittance provided in the embodiments of this application;
[0034] Figure 8 yes Figure 7 A magnified admittance diagram at point A in the middle;
[0035] Figure 9 This is the second schematic diagram of filter admittance provided in the embodiments of this application.
[0036] Figure label:
[0037] The capacitor structure is 100, the first finger bar region is 101, the second finger bar region is 102, the first target finger bar is 110, the second target finger bar is 120, and the bus bar is 130.
[0038] The resonator structure 200 includes a first finger bar 210, a surface acoustic wave resonator 201, and a longitudinally coupled resonator 202. Detailed Implementation
[0039] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.
[0040] The following is for reference. Figures 1-9 This application describes a surface acoustic wave (SAW) filter according to embodiments thereof, and an electronic device including the SAW filter.
[0041] like Figure 1 As shown, the surface acoustic wave filter of this application embodiment includes a resonator structure 200 and a capacitor structure 100, with the capacitor structure 100 connected in parallel with the resonator structure 200.
[0042] Among them, the resonator structure 200 is the structure in the surface acoustic wave filter that realizes signal processing tasks such as frequency selection and signal coupling, and the capacitor structure 100 is the matching element of the resonator structure 200.
[0043] It is understandable that the parallel capacitor structure 100 of the resonator structure 200 can reduce the difference between the resonant frequency and the anti-resonant frequency in the resonator structure 200, thereby narrowing the transition band of the surface acoustic wave filter and improving the rectangularity of the surface acoustic wave filter.
[0044] In this embodiment, the resonator structure 200 has a first finger 210 extending along a first direction.
[0045] It should be noted that the resonator structure 200 is fabricated on a piezoelectric substrate. The resonator structure 200 includes two sets of interlaced and periodically distributed metal strips (i.e., interdigitated electrodes). The first finger strip 210 is the electrode finger strip of the resonator structure 200. The direction perpendicular to the first finger strip 210 is the direction of elastic wave propagation, defined as the X direction, and the direction parallel to the first finger strip 210 is defined as the Y direction.
[0046] In this embodiment, such as Figure 2 As shown, the capacitor structure 100 includes two busbars 130 disposed opposite to each other, and a target finger bar is provided between the two busbars 130, which is connected to one of the busbars 130 and spaced apart from the other busbar 130, the target finger bar extending along a second direction.
[0047] It is understood that the capacitor structure 100 can be fabricated on the same chip as the resonator structure 200 by fabricating an IDT. The capacitor structure 100 includes two bus bars 130 arranged opposite each other. The target finger is the electrode finger of the capacitor structure 100. The target finger is located between the two bus bars 130 arranged opposite each other. The target finger is connected to one of the bus bars 130 and spaced apart from the other bus bar 130.
[0048] like Figure 2 As shown, the capacitor structure 100 is divided into an alternating first finger bar region 101 and a second finger bar region 102 along the length of the bus bar 130. The target finger bar in the first finger bar region 101 is the first target finger bar 110, and the target finger bar in the second finger bar region 102 is the second target finger bar 120.
[0049] In some embodiments, the first target fingers 110 are evenly arranged in the first finger bar region 101. In the first finger bar region 101, a plurality of first target fingers 110 alternately connect the upper and lower busbars 130, and the spacing (distance along the length direction of the busbar) between two adjacent first target fingers 110 is the same.
[0050] For example, the first target bar 110 is connected to the upper bus bar 130, the second target bar 110 is connected to the lower bus bar 130, and the third target bar 110 is connected to the upper bus bar 130. The distance between the first and second target bars 110 is d, and the distance between the second and third target bars 110 is d.
[0051] It should be noted that the pointer parameters of the first target pointer 110 and the second target pointer 120 are different.
[0052] The capacitor structure 100 is provided with a first finger bar region 101 and a second finger bar region 102. The finger bar parameters of the two finger bar regions 101 and 102 are different, which makes the capacitor structure 100 form a non-uniform interdigitated transducer finger bar structure. The surface acoustic waves excited by the first target finger bar 110 located on both sides of the second finger bar region 102 are different in phase and can cancel each other out, effectively reducing the excitation intensity of clutter. Rotating the piezoelectric substrate to change the placement direction of the finger bars will not deteriorate the out-of-band suppression characteristics of the filter.
[0053] In some embodiments, the finger bar parameters include at least one of the finger bar width and the finger bar connection bus bar position.
[0054] In actual execution, the widths of the first target finger bar 110 and the second target finger bar 120 are different. For example, the width of the second target finger bar 120 is greater than the width of the first target finger bar 110.
[0055] In related technologies, the finger placement direction of the resonator unit in the filter needs to be perpendicular to the direction of strong surface acoustic wave excitation. Usually, the finger placement direction of the capacitor unit is perpendicular to the finger placement direction of the resonator unit, so that the surface acoustic wave excited by the capacitor unit is reduced. If the surface acoustic wave excited by the capacitor unit is strong or the finger placement direction is changed by rotation within the piezoelectric substrate, strong clutter resonance peaks will be generated at the corresponding frequency points. The resonance peak of the capacitor falls outside the passband or farband of the filter, resulting in the deterioration of the filter performance.
[0056] In this embodiment, a first finger strip region 101 and a second finger strip region 102 are provided in the capacitor structure 100. By inserting the second finger strip region 102 between the uniformly arranged first finger strip regions 101, and adjusting the finger strip parameters such as the finger strip width and the position of the finger strip connecting to the busbar in the second finger strip region 102, the capacitor structure 100 forms a non-uniform interdigitated transducer finger strip structure. The surface acoustic waves excited by the first target finger strips 110 on both sides of the second finger strip region 102 have different phases and can cancel each other out, effectively reducing the excitation intensity of clutter. Rotating the piezoelectric substrate to change the placement direction of the finger strips will not deteriorate the out-of-band suppression characteristics of the filter.
[0057] According to the surface acoustic wave filter provided in the embodiments of this application, by dividing the capacitor structure 100 into a first finger bar region 101 and a second finger bar region 102, the finger bar parameters of the two finger bar regions are different, so that the capacitor structure 100 forms a non-uniform interdigitated transducer finger bar structure, and the surface acoustic waves with different phases are excited to cancel each other out, which can reduce the excitation of clutter. Even if the finger bar placement direction is changed by rotation within the piezoelectric substrate, the out-of-band suppression characteristics of the filter will not be deteriorated, thus ensuring the passband and out-of-band performance of the filter.
[0058] In some embodiments, such as Figure 2As shown, the entire capacitor structure IDT is provided with a second finger bar region 102, having at least one second target finger bar 120, the finger bar width of the second target finger bar 120 being greater than the finger bar width of the first target finger bar 110.
[0059] In this embodiment, one or more second target fingers 120 may be provided in the second finger bar region 102. The width of the second target fingers 120 is greater than the width of the first target fingers 110 in the first finger bar region 101. The second target fingers 120 is a wide finger bar electrode compared to the first target fingers 110.
[0060] In some embodiments, such as Figure 3 As shown, the entire capacitor structure IDT is provided with multiple second finger bar regions 102, and a second target finger bar 120 is provided in the second finger bar region 102. The finger bar width of the second target finger bar 120 is greater than the finger bar width of the first target finger bar 110.
[0061] In this embodiment, the surface acoustic waves excited by the first target fingers 110 on both sides of the wide finger electrode (i.e., the second target finger 120) are out of phase and cancel each other out, which can effectively reduce the excitation intensity of clutter and ensure the passband and out-of-band performance of the filter.
[0062] In some embodiments, the width of the second target finger bar 120 is 1.5 to 4.5 times the width of the first target finger bar 110.
[0063] The following is an example of simulation performed on a Y42-X lithium tantalate substrate.
[0064] The example is as follows Figure 2 The entire capacitor structure 100 shown has a second finger bar region 102, and a second target finger bar 120 is set in the second finger bar region 102. The width of the second target finger bar 120 is three times the width of the first target finger bar 110.
[0065] like Figure 7 and Figure 8 As shown, P1 and P2 characterize the capacitor cells with uniformly distributed finger strips in the related technology.
[0066] Wherein, P1 is the frequency admittance relationship between the finger placement direction of the capacitor unit and the finger placement direction of the resonator unit. The surface acoustic wave excited along the X direction is very strong, and the admittance amplitude is about -20dB.
[0067] P2 represents the frequency admittance relationship between the finger placement direction of the capacitor unit and the finger placement direction of the resonator unit. Different finger placement directions result in different excited sound wave intensities. Compared to P1, rotating the finger placement direction of the capacitor unit by 90° results in a weaker excited surface acoustic wave, such as... Figure 8As shown, the admittance of P2 is reduced by -24dB compared to P1.
[0068] P3 represents the capacitor structure 100 in Embodiment 2 of this application. Only one second finger strip region 102 is provided in the capacitor IDT. The second finger strip region 102 is provided with a second target finger strip 120. The width of the second target finger strip 120 is three times the width of the first target finger strip 110. The finger strip placement direction of the capacitor structure 100 is perpendicular to the finger strip placement direction of the resonator structure 200. Figure 8 As shown, the admittance amplitude of P3 is reduced by 2dB compared to P2, which reduces the excitation intensity of clutter.
[0069] It should be noted that for certain tangential lithium tantalate or lithium niobate substrates, the surface acoustic waves excited along the X direction are relatively strong, while those excited along the Y direction are relatively weak. For other tangential lithium tantalate or lithium niobate substrates, the surface acoustic waves excited along the finger direction of the in-plane rotating capacitor structure 100 are relatively strong. A greater number of second target fingers 120 (i.e., wide electrode fingers) can be set in the capacitor structure 100 to reduce the excitation intensity of clutter.
[0070] In order to set more second finger strip regions 102 in the capacitor structure 100, in actual implementation, the number of first target fingers 110 in each first finger strip region 101 is reduced. At the same time, in order to ensure that the capacitance value of the capacitor structure 100 remains unchanged, the total number of first target fingers 110 is the same as the original number of first target fingers 110. Therefore, the number of corresponding first finger strip regions 101 needs to be increased, and the number of second finger strip regions 102 between the first finger strip regions 101 also increases accordingly, so that the capacitor structure 100 has a larger number of second target fingers 120.
[0071] The following is a specific example.
[0072] like Figure 3 As shown, the entire capacitor structure IDT is provided with multiple second finger bar regions 102, and a second target finger bar 120 is provided in the second finger bar region 102. The width of the second target finger bar 120 is three times the width of the first target finger bar 110.
[0073] like Figure 9 As shown, simulations were performed on an X-cut lithium niobate substrate. The comparative example is the frequency admittance relationship corresponding to a traditional interdigitated electrode (i.e., a capacitor unit with uniformly distributed fingers in related technologies). The finger placement direction of the capacitor unit is parallel to the finger placement direction of the resonator unit.
[0074] Example 1 is Figure 3 The frequency admittance relationship corresponding to 8 first target fingers 110 is set in the first finger bar region 101 shown in Embodiment 2. Figure 3The frequency admittance relationship of four first target fingers 110 is set in the first finger bar region 101 shown. The finger bar placement direction of the capacitor structure 100 is parallel to the finger bar placement direction of the resonator structure 200.
[0075] like Figure 9 As shown, when 8 first target bars 110 are set, the admittance amplitude is reduced by 20dB compared with the related technology. When 4 first target bars 110 are set, the admittance amplitude is reduced by 32dB compared with the related technology. By reducing the number of first target bars 110 and increasing the number of second target bars 120 in the capacitor structure 100, the excitation intensity of clutter can be effectively reduced.
[0076] In this embodiment, by adjusting the number of second target fingers 120 in the capacitor structure 100, it is not necessary to set the finger placement direction of the capacitor structure 100 to be perpendicular to the finger placement direction of the resonator structure 200. This can also effectively reduce the noise generated by the capacitor structure 100 and improve the filter performance.
[0077] In some embodiments, the second finger bar region 102 has at least two second target finger bars 120, and within the second finger bar region 102, at least two second target finger bars 120 are connected to the same bus bar 130.
[0078] In this embodiment, all the second target fingers 120 within the second finger area 102 are connected to the same busbar 130.
[0079] In actual implementation, multiple second target fingers 120 within the second finger region 102 are connected to the same busbar 130, and the first finger region 101 can be connected to different busbars 130, so that the sound waves excited by the first finger regions 101 on both sides of the second finger region 102 are out of phase, and the sound waves superimpose and cancel each other out, effectively reducing the noise generated.
[0080] In some embodiments, the second finger bar region 102 has at least two second target finger bars 120, and within the second finger bar region 102, at least two second target finger bars 120 are connected to the same bus bar 130; within the first finger bar region 101, two adjacent first target finger bars 110 are connected to different bus bars 130.
[0081] like Figure 4 As shown, in the first finger bar region 101, two adjacent first target finger bars 110 are connected to different bus bars 130. The first first target finger bar 110 is connected to the upper bus bar 130, the second first target finger bar 110 is connected to the lower bus bar 130, and the third first target finger bar 110 is connected to the upper bus bar 130. In the second finger bar region 102, two second target finger bars 120 are connected to the lower bus bar 130.
[0082] In this embodiment, the first target fingers 110 in the first finger bar region 101 are uniformly arranged. By adjusting the polarity of the second target fingers 120 connected to the busbar in the second finger bar region 102, that is, adjusting the position of the fingers connected to the busbar, the acoustic waves excited by the first finger bar regions 101 on both sides of the second finger bar region 102 of the capacitor structure 100 are opposite in phase, and the acoustic waves superimpose and cancel each other, reducing the excitation of noise and ensuring the passband and out-of-band performance of the filter.
[0083] In some embodiments, the angle between the resonator finger direction and the capacitor finger direction is 0°-90°.
[0084] In this embodiment, by adjusting the finger width of the target finger in the second finger region 102 of the capacitor structure 100 and the finger connection position to the bus bar (i.e., the polarity of the finger connection to the bus bar is different), the excitation of clutter on the capacitor structure 100 is reduced. The capacitor structure 100 can be flexibly placed in the surface acoustic wave filter. The angle between the capacitor finger direction (i.e., the second direction) of the capacitor structure 100 and the resonator finger direction (i.e., the first direction) of the resonator structure 200 can be set in the range of 0°-90°.
[0085] By adjusting the finger parameters such as the finger width and finger position of the target finger in the second finger region 102 of the capacitor structure 100, the capacitor structure 100 forms a non-uniform interdigitated transducer finger structure, reducing the excitation of clutter. The width of the first target finger 110 and the width of the first finger 210 can be the same or different.
[0086] In some embodiments, the width of the first target finger strip 110 is the same as the width of the first finger strip 210.
[0087] In related technologies, to avoid clutter generated by capacitor units falling into the passband of the filter, the wavelength of the capacitor unit's fingers is often 10%-30% smaller than that of the resonator unit's fingers. This ensures that the clutter generated by the capacitor unit falls outside the high-end band of the filter. The fingers of the capacitor unit are much thinner than those of the resonator unit, meaning the width of the capacitor unit's fingers is smaller than that of the resonator unit's fingers. The two types of fingers have poor single-exposure performance and require double-exposure, which increases the filter's manufacturing cost.
[0088] In this embodiment, the non-uniform interdigitated transducer bar structure of the capacitor structure 100 is designed to effectively reduce the excitation of clutter. Even if the capacitor structure 100 uses the same wavelength as the resonator structure 200, the passband and out-of-band performance of the filter will not be degraded. The width of the first target bar 110 and the width of the first bar 210 can be the same, which allows for easy one-time exposure to obtain the bar of the capacitor structure 100 and the bar of the resonator structure 200 integrated on the piezoelectric substrate, resulting in a miniaturized, high-rectangularity surface acoustic wave filter.
[0089] In some embodiments, the width of the first target finger bar 110 and the width of the first finger bar 210 may also be different.
[0090] In some embodiments, such as Figure 5 As shown, the resonator structure 200 includes a surface acoustic wave resonator 201, which has a first finger strip 210 extending along a first direction.
[0091] Among them, the surface acoustic wave resonator 201 (SAWR) features high Q value (quality factor), low insertion loss, good temperature stability, miniaturization, and easy integration.
[0092] In some embodiments, such as Figure 6 As shown, the resonator structure 200 includes a longitudinally coupled resonator 202, which has a first finger 210 extending along a first direction.
[0093] Among them, the longitudinally coupled resonator 202 (Couple Resonator Filter, CRF) features high selectivity, high carrier quality factor, and small area.
[0094] In actual implementation, the resonator structure 200 of the surface acoustic wave filter may include a surface acoustic wave resonator 201 and a longitudinally coupled resonator 202.
[0095] The surface acoustic wave (SAW) filter of this application embodiment, by adjusting the finger parameters such as the finger width of the target finger in different finger regions and the position of the finger connecting to the busbar in the capacitor structure 100, designs a non-uniform interdigitated transducer finger structure of the capacitor structure 100, reduces the excitation of clutter, and ensures the filter performance. The capacitor structure 100 can be flexibly placed in the SAW filter, and the finger width of the capacitor structure 100 can be the same as or different from the finger width of the resonator structure 200. The finger strips of the capacitor structure 100 and the resonator structure 200 integrated on the piezoelectric substrate can be easily obtained in a single exposure, resulting in a miniaturized, high-rectangularity SAW filter.
[0096] This application also provides an electronic device that includes the surface acoustic wave filter as described above.
[0097] The electronic device can be a wireless communication terminal or other devices besides a terminal. For example, the electronic device can be a mobile phone, tablet computer, laptop computer, in-vehicle electronic device, mobile internet device (MID), augmented reality (AR) / virtual reality (VR) device, robot, wearable device, etc.
[0098] According to the electronic device provided in the embodiments of this application, by dividing the capacitor structure 100 into a first finger strip region 101 and a second finger strip region 102, the finger strip parameters of the two finger strip regions are different, so that the capacitor structure 100 forms a non-uniform interdigitated transducer finger strip structure, and the surface acoustic waves with different phases are excited to cancel each other out, which can reduce the excitation of clutter. Even if the finger strip placement direction is changed by rotation within the piezoelectric substrate, the out-of-band suppression characteristics of the filter will not be deteriorated, thus ensuring the passband and out-of-band performance of the filter.
[0099] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.
[0100] In the description of this application, it should be understood that the terms "center", "length", "width", "upper", "lower", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.
[0101] In the description of this application, "first feature" and "second feature" may include one or more of the features.
[0102] In the description of this application, "multiple" means two or more.
[0103] In the description of this application, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or the first and second features being in contact through another feature between them.
[0104] In the description of this application, the terms "above," "over," and "on top" for the first feature and the second feature include the first feature being directly above or diagonally above the second feature, or simply indicate that the first feature is at a higher horizontal level than the second feature.
[0105] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0106] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.
Claims
1. A surface acoustic wave filter, characterized in that, include: A resonator structure having a first finger extending along a first direction; A capacitor structure is connected in parallel with the resonator structure. The capacitor structure includes two busbars arranged opposite to each other. Between the two busbars is a target finger bar that is connected to one of the busbars and spaced apart from the other busbar. The target finger bar extends along a second direction. The capacitor structure is divided into alternating first finger bar regions and second finger bar regions along the length direction of the busbars. The target finger bar in the first finger bar area is the first target finger bar, and the target finger bar in the second finger bar area is the second target finger bar. The finger bar parameters of the first target finger bar and the second target finger bar are different.
2. The surface acoustic wave filter according to claim 1, characterized in that, The finger bar parameters include at least one of the finger bar width and the finger bar connection bus bar position.
3. The surface acoustic wave filter according to claim 2, characterized in that, The second finger strip region has at least one second target finger strip, and the width of the second target finger strip is greater than the width of the first target finger strip.
4. The surface acoustic wave filter according to claim 3, characterized in that, The width of the second target finger strip is 1.5 to 4.5 times the width of the first target finger strip.
5. The surface acoustic wave filter according to claim 3, characterized in that, The second finger strip region has at least two second target fingers, and the at least two second target fingers are connected to the same busbar within the second finger strip region.
6. The surface acoustic wave filter according to claim 2, characterized in that, The second finger strip region has at least two second target finger strips, and within the second finger strip region, the at least two second target finger strips are connected to the same busbar; Within the first finger strip area, two adjacent first target finger strips are connected to different busbars.
7. The surface acoustic wave filter according to claim 1, characterized in that, The first target finger strips are evenly distributed within the first finger strip area.
8. The surface acoustic wave filter according to any one of claims 1-7, characterized in that, The angle between the interdigitated direction of the resonator and the interdigitated direction of the capacitor in the surface acoustic wave filter is 0°-90°, the interdigitated direction of the resonator is the first direction, and the interdigitated direction of the capacitor is the second direction.
9. The surface acoustic wave filter according to any one of claims 1-7, characterized in that, The width of the first target finger bar is the same as the width of the first finger bar.
10. The surface acoustic wave filter according to any one of claims 1-7, characterized in that, The width of the first target finger bar is different from the width of the first finger bar.
11. The surface acoustic wave filter according to any one of claims 1-7, characterized in that, The resonator structure includes a surface acoustic wave resonator or a longitudinally coupled resonator.
12. An electronic device, characterized in that, include: The surface acoustic wave filter as described in any one of claims 1-11.