Near-synchronous dual-mode surface acoustic wave resonator

Abstract

An apparatus for a surface acoustic wave (SAW) apparatus having a dual mode (DMS) resonator configuration with near-synchronous operation is disclosed. One aspect includes a piezoelectric material, a first reflector disposed over the piezoelectric material, a second reflector disposed over the piezoelectric material, and a plurality of interdigital transducers (IDTs) disposed over the piezoelectric material and positioned between the first reflector and the second reflector, wherein a pitch of the electrode fingers in the first reflector and the second reflector is greater than a pitch of the electrode fingers in the plurality of interdigital transducers, and wherein a variation in the pitch of the electrode fingers in the plurality of interdigital transducers is less than 3% across the plurality of interdigital transducers.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to electronic communications. For example, aspects of the present disclosure relate to surface acoustic wave (SAW) resonators, and in particular to dual-mode SAW (DMS) resonators designed to reduce passband resonance peaking. BACKGROUND

[0002] Electronic devices include traditional computing devices such as desktop computers, notebook computers, tablet computers, smartphones, wearable devices like smartwatches, internet servers, and the like. These various electronic devices provide information, entertainment, social interaction, security, safety, productivity, transportation, manufacturing, and other services to human users. Many of the functions of these various electronic devices rely on wireless communication. Wireless communication systems and devices are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and the like. These systems can be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such systems include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, and Orthogonal Frequency Division Multiple Access (OFDMA) systems (e.g., a Long Term Evolution (LTE) system or a New Radio (NR) system). Wireless communication transceivers used in these electronic devices often include multiple radio frequency (RF) filters for filtering signals at a particular frequency or range of frequencies. Electroacoustic devices (e.g., “acoustic filters”) are used in many applications to filter high frequency (e.g., typically greater than 100 MHz) signals. Using a piezoelectric material as a vibration medium, an acoustic resonator operates by transforming an electrical signal wave propagating along an electrical conductor into an acoustic wave propagating via the piezoelectric material. The acoustic wave propagates at a speed having a magnitude much smaller than the propagation speed of electromagnetic waves. Generally, the magnitude of the propagation speed of a wave is proportional to the wavelength size of the wave. Thus, after transforming an electrical signal into an acoustic signal, the wavelength of the acoustic signal wave is significantly smaller than the wavelength of the electrical signal wave. The resulting smaller wavelength of the acoustic signal enables the use of smaller filter devices to perform filtering. This permits the use of acoustic resonators in electronic devices having size constraints such as the electronic devices listed above (e.g., including particularly portable electronic devices such as cellular telephones). SUMMARY

[0003] Systems, apparatuses, methods, and computer readable media for electronic communications are disclosed, and more specifically, devices, wireless communication apparatuses, and circuits implementing dual-mode surface acoustic wave (DMS) are disclosed.

[0004] In one aspect, an apparatus is provided. The apparatus includes a dual mode surface acoustic wave (DMS) resonator including: a piezoelectric material, a first reflector disposed above the piezoelectric material, a second reflector disposed above the piezoelectric material, a plurality of interdigital transducers (IDTs) disposed above the piezoelectric material and positioned between the first reflector and the second reflector, wherein a magnitude of a pitch of electrode fingers in the first reflector and the second reflector is higher than a pitch of electrode fingers in the plurality of interdigital transducers, wherein a variation of the pitch of the electrode fingers in the plurality of interdigital transducers is less than 3% across the plurality of interdigital transducers.

[0005] Some such aspects are configured where a metallization ratio of electrode fingers in a transition region formed by a subset of five or fewer fingers on either side of an adjacent IDT of the plurality of IDTs is greater than a metallization ratio of electrode fingers outside the transition region.

[0006] In other aspects, another apparatus is provided. The apparatus includes a dual mode surface acoustic wave (DMS) resonator including: a piezoelectric material, a first reflector disposed above the piezoelectric material, a second reflector disposed above the piezoelectric material, a plurality of interdigital transducers (IDTs) disposed above the piezoelectric material and positioned between the first reflector and the second reflector, wherein electrode fingers along the plurality of interdigital transducers are formed to have a pitch distribution along the plurality of interdigital transducers that is opposite to a formation of a cavity resonant mode between adjacent interdigital transducers of the plurality of transducers.

[0007] Some such aspects are configured where the pitch distribution corresponds to a near constant pitch with a variation of the pitch along the plurality of interdigital transducers greater than zero and less than 3%. Some such aspects are configured where a magnitude of a pitch of the first reflector and the second reflector is greater than a magnitude of a pitch along the plurality of interdigital transducers.

[0008] In other aspects, another apparatus is provided. The apparatus includes a dual-mode surface acoustic wave (DMS) resonator, the DMS resonator including: a piezoelectric material; a first interdigital transducer (IDT) disposed over a surface of the piezoelectric material, the first IDT including: a first busbar, a second busbar parallel to the first busbar, and a first plurality of IDT electrode fingers in an interdigital configuration, the first plurality of IDT electrode fingers including first IDT electrode fingers extending from the first busbar toward the second busbar and second IDT electrode fingers extending from the second busbar toward the first busbar; and a second IDT disposed adjacent to the first IDT over the surface of the piezoelectric material along an interface region between the first IDT and the second IDT, the second IDT including: a third busbar, a fourth busbar parallel to the third busbar, and a second plurality of IDT electrode fingers in an interdigital configuration, the second plurality of IDT electrode fingers including third IDT electrode fingers extending from the third busbar toward the fourth busbar and fourth IDT electrode fingers extending from the fourth busbar toward the third busbar, wherein the first IDT and the second IDT each include a transition region including five or fewer electrode fingers closest to the interface region, and wherein a chirp variation in the transition region is non-zero, and wherein the chirp variation in the transition region is less than plus or minus three percent.

[0009] Some such aspects are configured where the five or fewer electrode fingers have a transition area metallization ratio that is lower or greater than a metallization ratio of electrode fingers outside of the transition region of the first IDT and the second IDT. Some such aspects are configured where the transition area metallization ratio is less than fifteen percent lower or greater than the metallization ratio of electrode fingers outside of the transition region. Some such aspects are configured where the first plurality of IDT electrode fingers consists of 7 to 15 electrode fingers, and the second plurality of IDT electrode fingers consists of 7 to 15 electrode fingers. Some such aspects are configured where an electroacoustic cavity resonance around the first interface region between the first IDT and the second IDT is below a threshold to limit local energy in the transition region. Some such aspects are configured where the threshold is set to limit local energy in the transition region, and allow a continuous power level of 24 decibels (dBm) or greater in the apparatus.

[0010] Some such aspects are configured where a level of self-harmonic generation power in the apparatus is comparable to a level of self-harmonic generation power using a pure ladder section of the same stack with comparable insertion loss and attenuation performance.

[0011] Some such aspects are configured where a second mode of the DMS resonator is defined by a distance between the first IDT reflector and the second IDT reflector.

[0012] Some such aspects further include a first IDT reflector, a second IDT reflector, where the first IDT and the second IDT are disposed between the first IDT reflector and the second IDT reflector. Some such aspects are configured where a passband of a filter formed by the DMS resonator is formed substantially based on acoustic waves formed between the first IDT reflector and the second IDT reflector by the second mode.

[0013] Some such aspects are configured where a passband of a filter formed by the DMS resonator is formed substantially based on acoustic waves formed by the first mode and the second mode.

[0014] Some such aspects further include a third IDT adjacent to the second IDT on an opposite side from the first IDT. Some such aspects further include a plurality of additional IDTs positioned with their busbars along a line shared with busbars of the first IDT and the second IDT, where each IDT of the plurality of additional IDTs is adjacent to at least one adjacent IDT.

[0015] Some such aspects are configured where a first busbar of each additional IDT of the plurality of additional IDTs is coupled to the reference node, and where a second busbar of each additional IDT of the plurality of additional IDTs is coupled to the input node or the output node. Some such aspects are configured where a busbar of the plurality of additional IDTs coupled to the input node is adjacent to a busbar of the plurality of additional IDTs coupled to the reference node, and where a busbar of the plurality of additional IDTs coupled to the output node is adjacent to a busbar of the plurality of additional IDTs coupled to the reference node.

[0016] Some such aspects are configured where the bus bars of the plurality of additional IDTs coupled to the input nodes are adjacent to the bus bars of the plurality of additional IDTs coupled to the output nodes, and where the bus bars of the plurality of additional IDTs coupled to the reference nodes are adjacent to the bus bars of the plurality of additional IDTs coupled to the reference nodes. Some such aspects are configured where the first IDT, the second IDT, and the plurality of additional IDTs are made up of 15 or fewer IDTs. Some such aspects are configured where each IDT of the DMS resonator has a different corresponding chirp configuration from the electrode fingers of an adjacent IDT. Some such aspects are configured where the DMS resonator is disposed in a first DMS resonator element having an input node connection and an output node connection for each IDT. Some such aspects are configured where at least a first output node of the first DMS resonator element is electrically coupled to at least a first input node of a second DMS resonator element as part of a DMS resonator image impedance circuit. Some such aspects are configured where the first DMS resonator element is associated with a different DMS resonator configuration than a DMS resonator configuration associated with the second DMS resonator element, and the DMS resonator configuration associated with the second DMS resonator element and the different DMS resonator configuration associated with the first DMS resonator element are configured for impedance matching having a near zero susceptance at an inner reference plane connection between at least the first output node of the first DMS resonator element and at least the first input node of the second DMS resonator element. Some such aspects are configured where at least the first output node of the first DMS resonator element and at least the first input node of the first DMS resonator element are coupled via a first capacitor, and at least the first input node of the second DMS resonator element and at least the first output node of the second DMS resonator element are coupled via a second capacitor. Some such aspects are configured where the first capacitor has a capacitance value of 0 to 1 picofarad (pF) selected to fine tune a resonance frequency of a mode of the DMS resonator.

[0017] Some such aspects are configured where the DMS resonator is used in a transmit filter of a wireless communication device configured for power handling of at least 24 decibels (dBm).

[0018] Some such aspects are configured where the DMS resonator is disposed in a filter of a wireless communication device.

[0019] This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter. The subject matter should be understood from the entire specification, including the proper scope of the claims, any or all drawings, and the claims themselves.

[0020] The foregoing summary, as well as other features and embodiments, will be more apparent from a reading of the following description, taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1A Diagram of a perspective view of an example of an electroacoustic device.

[0022] Figure 1B Diagram of a side view of an electroacoustic device of Figure 1A

[0023] Figure 2A Diagram of a top view of an example of an electrode structure of an example electroacoustic device.

[0024] Figure 2B Diagram of a top view of an example of an electrode structure of an example electroacoustic device.

[0025] Figure 3A Diagram of a perspective view of another example of an electroacoustic device.

[0026] Figure 3B Diagram of a side view of an electroacoustic device of Figure 3A

[0027] Figure 4 Diagram of a view of an example electrode structure of an interdigital transducer (IDT) that can be used in a DMS resonator according to aspects described herein.

[0028] Figure 5A Diagram of a DMS resonator having two reflectors and two electroacoustic transducers according to some aspects described herein.

[0029] Figure 5B Aspects of a DMS resonator according to aspects described herein are illustrated.

[0030] Figure 5C Aspects of a near-synchronous DMS resonator according to aspects described herein are illustrated.

[0031] Figure 5D Diagram illustrating details of a DMS resonator configured for near-synchronous operation according to aspects described herein.

[0032] Figure 6 Diagram of a DMS resonator having two reflectors and three electroacoustic transducers according to some aspects described herein.

[0033] Figure 7 Diagram of a DMS resonator structure having two reflectors and any number (N) of electroacoustic transducers according to some aspects described herein.

[0034] Figure 8A ​​An example DMS resonator structure according to aspects described herein is illustrated.

[0035] Figure 8B An example of two DMS resonator structures in an image impedance configuration according to aspects described herein is illustrated.

[0036] Figure 8C An example of two DMS resonator structures in an image impedance configuration according to aspects described herein is illustrated.

[0037] Figure 8D An example circuit layout of two DMS resonator structures in an image impedance configuration according to aspects is illustrated.

[0038] Figure 8E A comparison between example physical layouts of non-DMS filters and DMS-like filters according to aspects described herein is provided.

[0039] Figure 9 is a flowchart illustrating a method of operation of a disclosed electroacoustic device according to examples described herein.

[0040] Figure 10 is a schematic representation of an example filter that can employ a disclosed electroacoustic device according to examples described herein.

[0041] Figure 11 is a functional block diagram of at least a portion of an example of a simplified wireless transceiver circuit in which a disclosed electroacoustic device described herein can be employed, according to examples described herein.

[0042] Figure 12 is a diagram of an environment including an electronic device that includes a wireless transceiver, such as Figure 11 a transceiver circuit of. DETAILED DESCRIPTION

[0043] The detailed description set forth below, in connection with the appended drawings, is intended as a description of exemplary implementations and is not intended to represent the only implementations in which the application can be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of the inventive concepts.

[0044] Electro-acoustic devices (e.g., "acoustic filters") can be used in many applications to filter high frequency (e.g., typically greater than 100 MHz) signals. Electro-acoustic filters are tuned to pass certain frequencies (e.g., frequencies within its passband) and attenuate other frequencies (e.g., frequencies outside its passband). Using piezoelectric material as a vibrating medium in a transducer, acoustic filters operate by transforming electrical signal waves propagating along an electrical conductor into acoustic waves (e.g., acoustic signal waves) formed on the piezoelectric material. The acoustic waves are then converted back into electrical filtered signals. Specifically, the cellular communications market uses such electro-acoustic devices. Within the cellular market, the market for wearable devices is growing rapidly. Aspects described herein can provide improvements to such wearable devices, where very efficient very light and small devices are preferred over devices that consume higher power.

[0045] Acoustic waves propagate on the piezoelectric material at a speed that is significantly less in magnitude than the speed of the electrical waves. Generally, the magnitude of the speed of propagation of a wave is proportional to the size of the wavelength of the wave. Thus, after transforming the electrical signal waves into acoustic waves, the wavelength of the acoustic waves is significantly smaller than the wavelength of the electrical signal waves. The resulting smaller wavelength of the acoustic waves enables the use of smaller filter devices to perform filtering. This permits acoustic filters to be used in space-limited devices, including portable electronic devices such as cellular telephones.

[0046] Dual-mode surface acoustic wave (DMS) resonators generally operate as described above, but multiple adjacent electro-acoustic transducers are positioned between reflector structures. A single transducer between two reflectors (e.g., a non-DMS SAW resonator operation) can generate a single mode (e.g., a synchronous resonator mode) between the reflectors. The use of multiple transducers in a DMS device allows multiple resonant modes (e.g., a synchronous resonator mode between outer reflectors, and one or more additional modes associated with the configuration of the multiple transducers in the DMS resonator). The multiple resonant modes can be configured in the design to synthesize a filter passband, allowing further size reduction and / or passband performance improvements beyond what is achievable using a single transducer SAW device.

[0047] Some DMS resonators include cavities between adjacent transducers, and significant asynchronous design elements, with up to 20% variation in pitch (e.g., chirp, or space between transducer fingers as described in more detail below) within the design of a single DMS resonator. Such cavity and / or chirp configurations can create strong spurious modes in the passband range by exciting spurious parasitic modes (e.g., shear, Rayleigh, etc.) near the modes between the reflectors of certain resonator layer stacks.

[0048] The aspects include DMS transducer configurations for limiting or removing such passband spikes. In some aspects, the DMS resonator is designed to have nearly constant finger period at the joint between adjacent transducers (e.g., for the fingers of an interdigital transducer of an electroacoustic resonator). In some aspects, DMS filter passband synthesis is performed using two modes that resonate in a cavity formed by two outer reflector structures (e.g., a mode between the reflectors and a second mode within the IDT, as described below). The transducer finger configuration reduces or eliminates cavity modes formed by the gap between adjacent transducers. The resonant frequency of the cavity mode can be configured at a higher frequency where spurious parasitic modes do not affect the resonator performance. Such DMS resonator filters can be optimized by adjusting the aperture (e.g., impedance), number of transducer fingers (e.g., impedance, bandwidth, attenuation), transducer and reflector finger period (e.g., frequency and reflector stopband), and transducer gap distance (e.g., bandwidth).

[0049] In addition to the benefits described above, in some aspects, DMS resonators configured for near-synchronous operation can provide manufacturing benefits associated with SiO2 gap fill behavior. In particular, as described herein, conventional DMS resonators have a transition area between the IDTs, where the fingers adjacent to the transition line between the IDTs have a higher frequency (e.g., less space between the IDT fingers). For certain frequency bands, the design of a certain IDT approaches or exceeds the manufacturability limits of the finger pitch. The DMS resonators described herein can be designed for such frequency bands without such high frequency finger pitch configurations.

[0050] These benefits can come with certain configurations, where for DMS resonators with a smaller number of IDTs, DMS resonators configured for near-synchronous performance can have reduced insertion loss performance, lower maximum achievable bandwidth, and higher impedance. In some aspects, the impedance issue can be compensated for by increasing the number of IDTs in the DMS resonator or combining aspects described herein with other resonators for implementations where the limitations associated with the aspects affect performance (e.g., a filter using a combination of near-synchronous IDTs and conventional IDTs).

[0051] Aspects of DMS resonator packages are described, and in some aspects, multiple DMS packages according to aspects described herein can be cascaded in an image impedance connection configuration. Some aspects, can provide additional tuning circuitry.

[0052] Various aspects of the disclosure will be described in relation to the figures.

[0053] Figure 1Ais a diagram of a perspective view of an example of an electroacoustic transducer 100. The electroacoustic transducer 100 can be configured as, or be a part of, a SAW resonator. In certain descriptions herein, the electroacoustic transducer 100 can be referred to as a SAW resonator. The electroacoustic transducer 100 includes an electrode structure 104, which can be referred to as an interdigital transducer (IDT), located on a surface of a piezoelectric material 102. The electrode structure 104 generally includes first and second comb electrode structures (conductive and typically metallic), with electrode fingers extending from two busbars toward each other, arranged in an interdigitated manner (e.g., in an interdigital manner) between the two busbars. An electrical signal, excited (e.g., an AC voltage applied) in the electrode structure 104, is transduced into an acoustic wave 106 that propagates in a particular direction via the piezoelectric material 102. The acoustic wave 106 is transduced back into an electrical signal and provided as an output. In many applications, the piezoelectric material 102 has a particular crystal orientation such that when the electrode structure 104 is arranged relative to the crystal orientation of the piezoelectric material 102, the acoustic wave propagates primarily in a direction perpendicular to the direction of the fingers (e.g., parallel to the busbars).

[0054] Figure 1B is Figure 1A a side view of the electroacoustic transducer 100 along a cross-section 107 shown. Figure 1A is a diagram of a perspective view of an example of an electroacoustic transducer 100. The electroacoustic transducer 100 can be configured as, or be a part of, a SAW resonator. In certain descriptions herein, the electroacoustic transducer 100 can be referred to as a SAW resonator. The electroacoustic transducer 100 includes an electrode structure 104, which can be referred to as an interdigital transducer (IDT), located on a surface of a piezoelectric material 102. The electrode structure 104 generally includes first and second comb electrode structures (conductive and typically metallic), with electrode fingers extending from two busbars toward each other, arranged in an interdigitated manner (e.g., in an interdigital manner) between the two busbars. An electrical signal, excited (e.g., an AC voltage applied) in the electrode structure 104, is transduced into an acoustic wave 106 that propagates in a particular direction via the piezoelectric material 102. The acoustic wave 106 is transduced back into an electrical signal and provided as an output. In many applications, the piezoelectric material 102 has a particular crystal orientation such that when the electrode structure 104 is arranged relative to the crystal orientation of the piezoelectric material 102, the acoustic wave propagates primarily in a direction perpendicular to the direction of the fingers (e.g., parallel to the busbars).

[0055] Figure 2A is a diagram of a perspective view of an example of an electroacoustic transducer 100. The electroacoustic transducer 100 can be configured as, or be a part of, a SAW resonator. In certain descriptions herein, the electroacoustic transducer 100 can be referred to as a SAW resonator. The electroacoustic transducer 100 includes an electrode structure 104, which can be referred to as an interdigital transducer (IDT), located on a surface of a piezoelectric material 102. The electrode structure 104 generally includes first and second comb electrode structures (conductive and typically metallic), with electrode fingers extending from two busbars toward each other, arranged in an interdigitated manner (e.g., in an interdigital manner) between the two busbars. An electrical signal, excited (e.g., an AC voltage applied) in the electrode structure 104, is transduced into an acoustic wave 106 that propagates in a particular direction via the piezoelectric material 102. The acoustic wave 106 is transduced back into an electrical signal and provided as an output. In many applications, the piezoelectric material 102 has a particular crystal orientation such that when the electrode structure 104 is arranged relative to the crystal orientation of the piezoelectric material 102, the acoustic wave propagates primarily in a direction perpendicular to the direction of the fingers (e.g., parallel to the busbars). Figure 2AA single-port configuration is generally illustrated. The electrode structure 204a has an IDT 205 that includes a first busbar 222 (e.g., a first electrically conductive segment or conductive trunk) electrically connected to a first terminal 220 and a second busbar 224 (e.g., a second electrically conductive segment or conductive trunk) spaced apart from the first busbar 222 and connected to a second terminal 230. A plurality of electrically conductive fingers 226 are connected to the first busbar 222 or the second busbar 224 in an interdigital fashion. The fingers 226 connected to the first busbar 222 extend toward the second busbar 224 but are not connected to the second busbar 224, such that there is a small gap between the ends of these fingers 226 and the second busbar 224. Similarly, the fingers 226 connected to the second busbar 224 extend toward the first busbar 222 but are not connected to the first busbar 222, such that there is a small gap between the ends of these fingers 226 and the first busbar 222.

[0056] In a direction along a shared line parallel to the busbars 222 and 224, there is an overlap region that includes a central region (as illustrated by the central region 225) in which a portion of one finger overlaps a portion of an adjacent finger. The central region 225 including this overlap can be referred to as an aperture, track, or active region at which an electric field is generated between the fingers 226 to cause a sound wave to propagate in the piezoelectric material 102. The periodicity of the fingers 226 is referred to as the pitch of the IDT. The pitch can be indicated in various ways. For example, in certain aspects, the pitch can correspond to the magnitude of the distance between the fingers in the central region 225. This distance can be defined, for example, as the distance between the center points of each of the fingers (and, when the fingers have a uniform thickness, can generally be measured between the right (or left) edge of one finger and the right (or left) edge of an adjacent finger). As described herein, a “higher” pitch refers to a section of the IDT in which the electrode fingers have a greater distance between adjacent electrode fingers, while a “lower” pitch refers to a section of the IDT in which the electrode fingers have a smaller distance between adjacent electrode fingers. In certain aspects, an average of the distances between adjacent fingers can be used for the pitch. Having the electrode fingers in some sections of the IDT have a given pitch characteristic that is different from the pitch characteristic of other sections of the IDT will allow for selection or control of signals (e.g., waves) that propagate through the IDT. The frequency at which the piezoelectric material vibrates is the self-resonance (also referred to as the “primary resonance”) frequency of the electrode structure 204a. This frequency is determined at least in part by the pitch of the IDT 205 and other characteristics of the electroacoustic device 100.

[0057] In some examples, the pitch characteristic of a section of the IDT can be constant pitch, i.e., the pitch does not vary significantly (e.g., varies within manufacturing tolerances, and is designed for a constant average pitch) across the IDT section. In other examples, the pitch characteristic of an IDT section can include a "chirped" pitch, i.e., the pitch varies in a predefined manner across the IDT section. For example, a chirped pitch can include an IDT section in which the pitch is designed to vary linearly across the IDT section, such that the pitch at one end of the IDT section is at a first value, the pitch at an opposite end of the IDT section is at a second value, and the pitch (e.g., the distance between electrode fingers) varies linearly between the two ends of the IDT section. In other examples, other non-linear variations in the pitch value across an IDT section can be used. By combining IDT sections with different pitch characteristics (e.g., a constant pitch at a first value and a constant pitch at a second value, or a constant pitch at a first value in one IDT section and a chirped pitch across a second IDT section), resonator characteristics can be designed for a given performance as described herein.

[0058] The IDT 205 is arranged between two reflectors 228 that reflect acoustic waves back towards the IDT 205 in order to convert the acoustic waves into electrical signals via the IDT 205 in the illustrated configuration, and to prevent loss (e.g., limit and prevent acoustic waves from escaping). Each reflector 228 has two busbars along a shared line with a grating structure of conductive fingers for the corresponding busbars of the IDT 205 and each connected to the two busbars. The pitch of the reflectors can be similar or the same as the pitch of the IDT 205 to reflect acoustic waves in the resonant frequency range. But many configurations are possible.

[0059] When converted back into electrical signals, the admittance or reactance measured between the two terminals (i.e., the first terminal 220 and the second terminal 230) is used as the signal for the electroacoustic transducer 100.

[0060] Figure 2B Diagram of a top view of another example of an electrode structure 204b of an electroacoustic device. In this instance, the electrode structure 204b includes a center IDT and reflectors 228 connected as illustrated. The electrode structure 204b is provided to illustrate various electrode structures and structural connections that can be used in accordance with aspects described herein.

[0061] It should be appreciated that while a certain number of fingers 226 are illustrated, the actual number of fingers, as well as the length and width of the fingers 226 and the busbars, can vary in actual implementations. Such parameters depend on the particular application of the filter and the desired frequencies. Moreover, the SAW filter can include multiple interconnected electrode structures, each including multiple IDTs to achieve a desired passband (e.g., multiple interconnected resonators or IDTs to form a desired filter transfer function).

[0062] Figure 3A is a diagram of a perspective view of another example of an electroacoustic device 300. The electroacoustic device 300 (e.g., which can be configured as or be part of a SAW resonator) is similar to Figure 1A the electroacoustic transducer 100 of Figure 1A but has a different layer stack. In particular, the electroacoustic device 300 includes a thin piezoelectric material 302 provided on a substrate 310 (e.g., silicon). Based on the type of piezoelectric material 302 used (e.g., typically relative to Figure 1A the electroacoustic transducer 100 of Figure 1A the electroacoustic device 300 can have a higher Q-factor compared to the electroacoustic transducer 100 of Figure 3A The piezoelectric material 302 can be, for example, lithium tantalate (LiTa03) or some doped variant. Another example of the piezoelectric material 302 can be lithium niobate (LiNb03). In general, the substrate 310 can be substantially thicker than the piezoelectric material 302 (e.g., by a factor of about 50 to 100, or more, as one example). The substrate 310 can include other layers, such as 310-1, 310-2, and 310-3 (or other layers can be included between the substrate 310 and the piezoelectric material 302).

[0063] Figure 3B is a diagram of a perspective view of another example of an electroacoustic device 300. The electroacoustic device 300 (e.g., which can be configured as or be part of a SAW resonator) is similar to Figure 3A the electroacoustic transducer 300 of Figure 3BIn the aspects shown, substrate 310 may include sublayers that may have higher resistance (e.g., relative to other layers—high resistivity layers), such as substrate sublayer 310-1 (e.g., made of silicon). Substrate 310 may also include trap-rich layers 310-2 (e.g., polycrystalline silicon, aluminum nitride (AlN), silicon nitride (SiN4), diamond-like carbon (DLC), and dielectric films with high acoustic velocities). Substrate 310 may also include compensation layers (e.g., silicon dioxide (SiO2) or another dielectric material) that can provide temperature compensation and other properties. These sublayers may be considered as part of substrate 310 or as separate layers on their own. A relatively thin layer of piezoelectric material 302 is provided on substrate 310 at a specific thickness to provide specific acoustic modes (e.g., with...). Figure 1A Compared to the electroacoustic transducer 100, the thickness of the piezoelectric material 102 is not a critical design parameter exceeding a certain thickness, and... Figure 3A and Figure 3B The piezoelectric material 302 of the electroacoustic device 300 may be thicker than it would typically be. The electrode structure 304 is positioned above the piezoelectric material 302. In addition, in some aspects, one or more layers (not shown) (e.g., a thin passivation layer) may be present above the electrode structure 304.

[0064] Based on the type, thickness, and overall layer stacking of the piezoelectric material, the electromechanical connection to the electrode structure 304 and the sound velocity within the piezoelectric material in different regions of the electrode structure 304 can be achieved between different types of electroacoustic devices, such as... Figure 1A Electroacoustic transducer 100 and Figure 3A and Figure 3B The electroacoustic devices vary among the 300 models.

[0065] Figure 4 This is a schematic diagram of an example electrode structure 400 of an interdigital transducer (IDT) that can be used in a DMS according to the aspects described herein. As described above, electrode structure 400 may be referred to as an IDT, which may be fabricated on the surface of a piezoelectric material as part of a resonator. Electrode structure 400 includes a first comb electrode and a second comb electrode. The comb teeth are located within a track 429 and are supported on one side by a busbar 402 and on the other side by a busbar 404. An electrical signal excited across the resonator by an electrical signal at input node 401 is converted into an acoustic wave propagating within the resonator. The acoustic wave is converted back to an electrical signal at output node 411. An external reflector (e.g., reflector 228) is used. Figure 4 (Not shown in the image) will have a similar configuration, but without barriers, so that each finger of the reflector is connected across the track region to connect to the two busbars.

[0066] As described above, multiple electrode structures 400 can be configured between the outer reflectors using the SAW details provided above for dual-mode SAW (DMS) resonators.

[0067] Figure 5A is a diagram of a DMS resonator 500 having two reflectors 528A, 528B and two electroacoustic interdigital transducers (IDTs) 505A, 505B according to some aspects described herein. As Figure 2A and Figure 2B , Figure 5A may be considered a diagram of a top view of an example of a resonator structure. Figure 5A A DMS resonator 500 is shown. The interface region between the two IDTs 505A, 505B is not to scale. Each of the IDTs 505A, 505B includes a first corresponding busbar 522A, 522B (e.g., a first conductive segment or track) electrically connected to a first terminal 520A, 520B and a second busbar 524A, 524B (e.g., a second conductive segment or track) spaced apart from the first busbar 522A, 522B and connected to a second terminal 530A, 530B. A plurality of corresponding conductive fingers 526A, 526B of each of the IDTs 505A, 505B includes busbars, with adjacent fingers coupled to opposite busbars in an interdigital fashion. Similar to Figure 4 , a central track region 525 of the conductive fingers provides a primary electroacoustic region for signal modes in the IDTs of the DMS resonator 500.

[0068] In addition to having multiple IDTs 505A, 505B, Figure 5A the interface region between the IDTs 505A, 505B in the DMS resonator 500 is also illustrated. Figure 5AA transition region 529 between IDTs 505A and 505B is also illustrated, which includes the electrode fingers of each IDT 505A, 505B closest to the transition region 529 associated with the elements of both IDTs 505A, 505B. In some aspects, the transition region 529 does not include electrode fingers. In other aspects, the transition region of a DMS resonator with near-synchronous operation includes up to two electrode fingers from each associated IDT on either side of the transition line between the two IDTs. In other aspects, five or fewer electrode fingers are included in the transition region, which are different in metallization and / or pitch from the metallization and / or pitch outside the transition region. The DMS resonator 500 can be configured in a variety of different ways according to the details described above. Variables for configuring the passband and other operational characteristics of the DMS resonator 500 can include the chirp or finger distance values associated with the interface region 521 (e.g., the distance between the fingers of adjacent IDTs around the interface region), variations in finger pitch and metallization ratio along any portion of any element of the DMS resonator 500 (e.g., reflectors 528A, 528B and IDTs 505A, 505B), the number of fingers 526A, 526B of any IDT of the DMS resonator 500, the chirp (e.g., finger pitch) values along any portion of any element of the DMS resonator 500, the number or pitch of fingers in the reflectors 528A, 528B, or any other such characteristic of a DMS resonator such as the DMS resonator 500 described herein. While the DMS resonator 500 includes two IDTs 505A, 505B, other aspects can include any number of IDTs. In some aspects, a DMS resonator can be configured with three to fifteen IDTs between a pair of reflectors, as further illustrated below. Each pair of adjacent IDTs will have an associated interface region 521 that influences the resonance, while providing electrically isolated input and output, in Figure 5A are illustrated as input terminals 520A, 520B and output terminals 530A, 530B.

[0069] Figure 5B Aspects of a DMS resonator 500 according to aspects described herein are illustrated. Figure 5B The acoustic modes that dominate the passband operation due to the various elements of the DMS resonator 500 are illustrated at a high level. The reflectors 528A and 528B, as well as the two IDTs 505A and 505B are shown. As described above, conventional DMS resonators are configured with an interface region 521 (e.g., a cavity region between the IDTs) that has a significant change in the finger period at the transition between the IDTs (e.g., a chirp at the transition between adjacent IDTs). Figure 5BA configuration is illustrated with an interface region 521 in which there is a cavity mode 3 in addition to mode 2 between the reflectors 528A, 528B and mode 1 within each of the IDTs 505A, 505B. Mode 2 pitch is produced by resonances within the constant pitch region of the transducer (e.g., where there are multiple reflections between the fingers of the synchronous portion of the IDT off of mode 2). Mode 1 can include high order modes that are primarily caused by reflections between the reflectors. Mode 3 can occur in the interface region 521 due to a large chirp associated with the interface region 521, such as a 10% to 20% or greater variation in the finger period. In some aspects, mode 3 results in excitation of spurious modes that can result in a few decibels (dB) of spikes in the passband range of the DMS resonator 500.

[0070] Figure 5C Aspects of a DMS resonator 500 configured for near-synchronous operation (e.g., with little pitch variation) to limit the interface region 521 are illustrated in accordance with aspects described herein. As illustrated, Figure 5C the DMS resonator 500 includes reflectors 528A, 528B and IDTs 505A, 505B, but where the interface region 521 is limited, minimized, or eliminated by device configuration. As illustrated, there are reflectors 528A, 528B and two IDTs 505A, 505B, but the transition area associated with the interface region 521 is designed to eliminate Figure 5B mode 3, leaving mode 2 and mode 1 electroacoustic signal dominant performance. In addition to showing the above details of the DMS resonator 500, Figure 5C an axis 599 is also included that illustrates the direction of a shared line parallel to the generatrix of the DMS resonator (e.g., both the IDT generatrix and the reflector generatrix) from the beginning of the reflector 528A along the two IDTs 505A, 505B to the end of the reflector 528B, which is used to describe the configuration of the near-synchronous operation of the DMS resonator 500 below.

[0071] Figure 5D is a chart illustrating details of a DMS resonator configured for near-synchronous operation in accordance with aspects described herein. The chart includes areas associated with the reflectors 528A, 528B and IDTs 505A, 505B that correspond to distances along the DMS resonator 500 as also illustrated by the axis 599 shown in Figure 5C The finger pitch line 551 shows the relative finger pitch associated with each location of each element of the DMS resonator 500 along the axis 599, where the axis 598 illustrates increasing pitch values (e.g., greater distances between the IDT fingers). Figure 5Dbottom of the plot along axis 599 is not associated with a 0 pitch value, but reflects an example of a relative pitch value according to some aspects. Details of pitch values and other configurations are provided below. The metallization ratio line 552 illustrates a relative metallization ratio associated with each location along axis 599 of each element of the DMS resonator 500, where axis 598 illustrates increasing metallization values (e.g., thicker IDT fingers). The element transition line 561 illustrates a location between the two IDTs 505A, 505B. The element transition line 561 is associated with a gap between the bus bars of the IDTs 505A, 505B, and can be associated with a chirp value in the area around the element transition line 561. In other DMS implementations, the characteristics around the element transition line 561 (e.g., as well as the interface region 521 around the element transition line 561) cause a cavity mode resonance, which is Figure 5B Mode 3. Mode 3 is associated with excitation of spurious modes and spurious responses in the passband. However, having a relative finger pitch as exemplified by Figure 5D the DMS as described herein reduces or limits any modes (e.g., Mode 3 of Figure 5B ) formed between adjacent IDTs within the structure that have a resonance within the passband of the filter. The aspects described herein having the characteristics described in Table 1 limit the modes (e.g., Mode 3 of Figure 5B ) formed between adjacent IDTs. In DMS resonators having more than two IDTs, for each pair of adjacent IDTs, there will be an element transition similar to the element transition of element transition line 561. The element transitions 562 and 563 are the transitions between the outermost IDTs and the adjacent reflectors (e.g., associated with the bus bar gap between elements).

[0072] Table 1 below provides configuration details of some aspects of the DMS resonator 500 configured for near-synchronous operation compared to configuration details of a conventional DMS resonator.

[0073]

[0074] Table 1

[0075] In Table 1, NFiW is the number of fingers attached to the bus bar of a given IDT. Figure 5DNfi 582 illustrates the area of the associated number of fingers in IDT 505A. For example, as described above, a single IDT of a DMS resonator will have separate bus bars that allow for isolated electrical input and output. Nfi 582 is the number of fingers (e.g., bus bars attached to IDT 505A) of the associated IDT 505A. Nfi 582 includes fingers in the center region and the transition region of IDT 505A. Other IDTs will have separate Nfi values along the width (e.g., long dimension of the corresponding bus bar) of each IDT.

[0076] Finger pitch line 551 illustrates the change in the chirp (e.g., finger frequency) along the IDT 505A associated with those fingers. Similarly, NFR is the number of fingers around element transition line 561 in the case where a gap occurs between the bus bars of IDT 505A and IDT 505B. NFR 584 is associated with the number of fingers around element transition line 561 that further configure the interface region 521 between adjacent IDTs. In Figure 5D The delta FPeW value, illustrated in the graph as dFPeW 585, is the change in the chirp of the finger frequency around element transition line 561 that is associated with the NFR 584 value (e.g., the number of fingers around element transition line 561). The delta ETA value is the change in the metallization ratio around element transition line 561 between IDTs. PRIR, illustrated in the graph as PRIR 580, is a measure of the maximum finger period change between the reflector and the adjacent IDT.

[0077] As illustrated in Table 1, some aspects in accordance with near-synchronous DMS configurations include an NFR region around element transition line 561 between two IDTs (e.g., as described above in relation to FIG. 5A). For example, as illustrated in Table 1, the NFR region around element transition line 561 between two IDTs can include a number of fingers (e.g., bus bars) that are configured to have a different finger pitch than the fingers of the IDTs on either side of the NFR region. Figure 5AThe illustrated transition region 529) has 0, 1, or 2 fingers (e.g., NFR is less than or equal to 2). In some alternative aspects, additional fingers can be present in the NFR transition region according to other configurations, allowing for additional fingers without creating a significant acoustic cavity at the element transition between adjacent IDTs. For example, some aspects can have up to 5 fingers in the NFR region, as described below. As shown, the transition can be chirped in a linear fashion, such that the distance between each finger changes in a linear fashion around the element transition line 561. This results in a constant rate of change of the pitch (e.g., dFPeW) for each pair of fingers, and a change in the element transition area and associated dFPeW 585 across the region (e.g., the average chirp across the region is approximately the same as the chirp between each pair of electrode fingers in the NFR 584 in the region around the element transition line 561). In other aspects, other chirp configurations can be used. Some such aspects operate with a chirp (e.g., change in finger periodicity) of less than 2% around the transition line 561 between IDTs, and a change in metallization ratio (e.g., absolute value, the change in metallization can be negative, as long as the manufacturing capability can achieve the change, so the change in metallization ratio can be up to + / - 10%) of greater than 0 and up to 10% around the IDT transition. A change in metallization ratio (e.g., associated with the NFR 584) of up to 10% around the transition line 561 allows for adjustment of the frequency resonance, and can be used to adjust the frequency resonance, as well as expand or reduce the bandwidth of the filter (e.g., to reduce the bandwidth if too much coupling occurs). Some aspects operate with 7 to 15 fingers for a given IDT (e.g., Nfi 582).

[0078] Figure 5D The particular implementations reflected in the middle reflect no limitations in the relative design of a DMS resonator configured for near-synchronous operation. For example, the relative pitch of the fingers within a given IDT can be higher or lower at any location within the DMS resonator in different implementations, as long as the design limits acoustic cavity resonance at the locations between the DMS resonator elements (e.g., between adjacent IDTs). In some aspects, for example, a DMS resonator designed for near-synchronous operation is configured to have an electro-acoustic cavity resonance below a threshold value that satisfies performance standards for implementation. The configurations detailed in Table 1 describe possible implementations of such near-synchronous DMS resonators. Other implementations are also possible within the scope of the aspects described. Additionally, as DMS resonators are scaled for different frequency bands, such configuration standards can be scaled based on the frequencies associated with the target frequency band of a given DMS resonator.

[0079] In particular, conventional DMS resonators are typically designed with a chirp between the IDTs, where the finger pitch around the element transitions is lower than the finger pitch in other central portions of the IDT (e.g., portions not near the element transitions) by up to 20%.

[0080]

[0081] Table 2

[0082] Table 2 shows configuration details for additional possible implementations of near-synchronous DMSs according to aspects described herein. In particular, Table 2 describes slight variations in the number of electrode fingers that can be slightly chirped in the transition regions between the IDTs, while limiting acoustic resonances between the IDTs in the DMS according to near-synchronous operation as described herein.

[0083] Figure 6 is a diagram of a DMS resonator 600 having two reflectors 628A, 628B and three IDTs 605A, 605B, 605C according to some aspects described herein. The DMS resonator 600 can be configured for near-synchronous operation and uses similar configurations to those detailed above for Table 1 and Figure 5D detailed configurations to limit the cavity resonances (e.g., similar to the resonances of the cavity resonant mode 3 from Figure 5B the illustrated interface region 521). For such configurations, any of the values of Table 1 can be used for any of the IDTs 605A, 605B, 605C, the reflectors 628A, 628B, and the transition regions 671, 672 between the reflectors 628A, 628B and the end IDTs, as well as the transitions 661, 662 between adjacent IDTs.

[0084] Figure 7 is a diagram of a DMS resonator 700 having two reflectors 728A, 728B and any number (N) of IDTs 705A and 705B through 705N according to some aspects described herein. Additionally, as shown, the DMS resonator 700 includes two transitions between the reflectors 728A, 728B and the end IDTs, as well as transitions 761A through 761(N-1) (e.g., because the number of transitions between adjacent IDTs (N-1) is one less than the number of IDTs N). As described above for the DMS resonators 600 and 500, the DMS resonator 700 can be configured for near-synchronous operation and uses similar configurations to those detailed above for Table 1 and Figure 5DA similar configuration is detailed to limit cavity resonance (e.g., from interface region 521). For such a configuration, any of the values of Table 1 can be used for any of IDT 705A-N, reflector 728A, 728B, transition regions 771, 772 between reflector 728A, 728B and end IDTs, and transitions 761A through 761(N-1) between adjacent IDTs. Such a configuration can be used for a DMS resonator with any number of IDTs, including a DMS resonator with three or more IDTs. In some aspects, 15 IDTs is the maximum number of IDTs for a given DMS resonator configuration. Additionally, such IDTs within a single DMS resonator can include variations of any such values. For example, within a single DMS resonator, a first IDT can have 15 fingers and a second IDT can have 7 fingers. Similarly, in accordance with aspects described herein, within a single DMS resonator, chirp, metallization values, and other such values can vary according to IDT within a single DMS resonator, and vary for transitions between different IDT pairs.

[0085] Figure 8A A circuit 800 with a DMS resonator element 801 is illustrated in accordance with aspects described herein. Figure 8A Node connections 828, 820A-C, and 830A-C of a DMS resonator element 801 are illustrated. Figure 8A A reference node 829 (e.g., a ground connection) coupled to various nodes of the DMS resonator element 801 is illustrated. Inside the DMS resonator element 801 is a DMS resonator with 3 IDTs similar to Figure 6 A DMS resonator with 3 IDTs similar to that of

[0086] In the illustrated circuit 800, input node 819 is connected to node connections 820A and 820C. Node connections 820B, 830A, and 830C are connected to reference node 829 (e.g., ground). Node connection 830B is connected to output node 831. Node connection 828 is open and not connected internally or externally. Circuit 800 can be included in a device, as a filter, as a resonator within a larger filter as described below, or within any other such device. In some aspects, DMS resonator element 801 has an associated size (e.g., layout footprint) of approximately 0.07 square millimeters (mm2). 2 ​

[0087] Figure 8B An example circuit 890 is shown for two DMS resonator elements 801, 802 in an image impedance configuration, in accordance with aspects described herein. The layout of DMS resonator element 801 on the internal reference plane 803 is the same as the layout of circuit 800 in Figure 8A However, node connection 830B is connected to node connection 840B of DMS resonator element 802, instead of to output node 831. Node connections 840A, 840C, and 850B are connected to reference node 829. Node connections 850A, 850C are connected to output node 832.

[0088] In circuit 890, since the two DMS resonator elements 801, 802 are similar (e.g., identical within normal manufacturing variation), the conductance and susceptance values of DMS resonator elements 801, 802 are equal or nearly equal. On the internal reference plane 803 connection between node connections 830B and 840B, there is maximum power transfer with a susceptance close to zero. This is referred to as an image impedance connection operation, and can allow for efficient use of a design of two DMS resonators in accordance with aspects described herein for a band filter, particularly when compared to a mismatch with a susceptance much greater than the conductance, and when the resulting mismatch increases the out-of-band rejection level.

[0089] In some aspects, the two DMS resonator elements 801, 802 are not identical devices, but rather different devices can be used for DMS resonator elements 801, 802, with the impedances matched to achieve the maximum power transfer described above. Such a configuration can allow for configuration of a band filter with additional design configurations, where the DMS resonators of DMS resonator elements 801, 802 have different characteristics, as long as the impedance matching is sufficient to meet the design criteria of the particular implementation.

[0090] Additionally, as detailed above, even with multiple DMS resonator structures, there can be layout benefits of the devices when compared to a single conventional DMS resonator. In some aspects, two DMS resonator structures and connection circuitry use approximately 0.17 mm 2 of surface area on a chip or substrate within a wireless device (e.g., a filter, transceiver, etc. as described in Figures 10 to 12 may be comparable to the design footprint of a single conventional DMS resonator. Even when associated with a similar footprint area, the presence of two separate elements (e.g., DMS resonator elements 801, 802) provides design flexibility, as placement of two separate elements with a similar layout footprint provides layout flexibility when compared to a single (e.g., non-adjustable) element with a fixed size.

[0091] Figure 8CAn example circuit 891 is shown according to aspects described herein having two DMS resonator elements 861, 862 in an image impedance configuration between an input 859 and an output 879, with shunt capacitors 871, 872 for image tuning. The DMS resonator elements 861, 862 are connected by electrical connections across the inner reference plane 803 as part of the image impedance configuration.

[0092] Figure 8C The circuit illustrates the connection nodes 861-1 through 861-22 of the DMS element 861 and the connection nodes 862-1 through 862-22 of the DMS element 862. Similar to the description above for the DMS element 801, each of the DMS elements 861 and 862 includes open end node connections, as well as a pair of node connections for each IDT (e.g., connection nodes 861-3 and 861-4 for the first IDT, etc.). As illustrated, the DMS resonator elements 861, 862 are connected in the circuit 891 with signal connections on one side of the elements and the reference node 869 (e.g., ground) on the other side of the elements. The connections of the circuit 891 result in all input / output nodes on one side of the elements and ground connections for each IDT on the opposite side of the elements. In other aspects, the input can be on one side and the output on the other side, with the ground connections for the IDTs connected to the output on the same side as the input connections, and the ground connections for the IDTs connected to the output on the same side as the output connections. In other aspects, other configurations can apply to circuits in which DMS resonators having configurations for near-synchronous operation are described.

[0093] The shunt capacitors 871, 872 are connected between the input signal path and the output signal path of each element track. The capacitors 871, 872 allow for individual tuning of the anti-resonant frequency of mode 2 for each element track. Tuning from the capacitors 871, 872 can be used to perform band tuning by adjusting the image mode and frequency location, as well as the impedance. Such tuning can also allow for adjustment of the steepness of the filter right skirt and the filter attenuation level. In some aspects, the capacitors 871, 872 can be selected (e.g., configured during device design) to be static capacitors with a capacitance value of 0 (e.g., no capacitor in the signal path) to 1 picofarad (pF). In some aspects, such configurations can be selected with a constraint of 0.2 pF steps. Such capacitors 871, 872 can further provide the benefit of design flexibility, with fine tuning of the DMS resonators in the filter.

[0094] Figure 8D is an example layout diagram of the circuit 891 according to some aspects. Figure 8DThe illustrated electrical connections show the surface area of the integrated circuit design or the substrate surface area occupied by the DMS resonator elements 861, 862. As shown, the input 859 follows a conductive path to a first set of input nodes on the left side of the DMS resonator element 861. A second set of output nodes on the left side of the DMS resonator element 861 is connected to a third set of input nodes on the right side of the element 862 across the electrical path of the internal reference plane 803. A fourth set of output nodes on the right side of the element 862 is connected to the output 879. The left side of the element 862 and the right side of the element 861 are coupled to a reference node 869 (e.g., ground). As noted above, while the DMS resonator elements 861, 862 are shown in a particular relative positioning, in other design layouts, these elements can be positioned in any relative space in proximity to one another, providing design flexibility, so long as the electrical connections provide performance sufficient to meet the device operational limitations. Similarly, while the input and output are illustrated on the same side in Figure 8D the example design layout 800, in other aspects, the input and output can be on opposite sides of the DMS resonator elements, while in other aspects, there are respective input and output nodes on each side between adjacent ground nodes.

[0095]

[0096] Table 3

[0097] Table 3 illustrates an example design configuration for a circuit 891 according to an aspect. According to some aspects, the design configuration of Table 3 can be used, for example, for a band 71 filter in a cellular communication system of a wireless communication device. The example filter includes 9 IDTs for a first DMS resonator element (e.g., DMS 1 similar to DMS resonator element 861) and 9 IDTs for a second DMS resonator element (e.g., DMS 2 similar to DMS resonator element 862). The first DMS resonator element has consecutive 7, 7, 11, 7, 11, 7, 11, 7, 7 fingers for the IDTs of the first DMS resonator. The second DMS resonator has a different IDT configuration, with the IDTs having respective numbers of fingers as indicated in Table 2. The characteristics of each IDT are described by the additional rows of Table 2 according to the descriptions in Table 1 above related to chirp, transition region metallization ratio, etc.

[0098] In some aspects, a DMS resonator can be configured or designed such that an electroacoustic cavity resonance around a first interface region between a first IDT and a second IDT is below a threshold to limit localized energy in the transition region. In some such aspects, such a threshold can be set to limit localized energy in the transition region and allow a sustained power level of 24 decibels (dBm) or more in the device.

[0099] In other respects, such DMS resonators can be configured or designed such that the level of self-harmonic generation power in the device (e.g., the local energy in the mode of the DMS resonator) is comparable to the level of self-harmonic generation power using a pure ladder segment with the same stack having comparable insertion loss and attenuation performance.

[0100] Figure 8E A comparison of example physical layouts between a non-DMS filter circuit 893 and a DMS-like filter 892, according to various aspects described herein, is provided. The dimensions of filter circuits 892 and 893 indicate that a similar (e.g., providing similar performance to meet device operating constraints) DMS filter 892 occupies almost 40% less area on the substrate surface.

[0101] As described in this article, near-synchronous DMS resonators can be used in filters (such as...) Figure 10 In the filter 1000, where a near-synchronous DMS resonator is used, similar performance can be provided with fewer steps (e.g., as...). Figure 10 As shown, each step or segment has two resonators (Rs and Rp). In some aspects, the DMS resonator can be configured such that the power in the DMS resonator is comparable to the power in a segment of a non-DMS resonator with comparable insertion loss and attenuation performance. For example, in some aspects, a duplexer with a non-DMS resonator can be redesigned with a DMS resonator to reduce the filter footprint (e.g., die size) by approximately 40% while providing comparable or improved performance. In some aspects, such a DMS filter 892 can be used in the receive (Rx) and transmit (Tx) paths of a wireless communication device, thereby significantly reducing the size of the chip used to implement the filter circuitry in each path.

[0102] Figure 9 This is a flowchart illustrating an example method 900 performed by a DMS resonator configured for near-synchronous operation, according to various aspects described herein. Method 900 is described in the form of a set of blocks specifying the operable operations. However, the operations are not necessarily limited to... Figure 9 The order shown or described herein is not specified, as these operations can be implemented in an alternative order or in a manner that is fully or partially overlapping. Furthermore, more, fewer, and / or different operations can be implemented to perform method 900 or other processes. In some aspects, method 900 can be performed by a device including circuitry configured for the operation of method 900. In some aspects, control circuitry of the device or one or more processors can be configured to perform the operations. In some aspects, method 900 can be implemented as instructions in a non-transitory computer-readable storage medium that, when executed by one or more processors of the device, cause the device to perform the operations of method 900.

[0103] At block 902, the method includes exciting an input node of a dual-mode surface acoustic wave (DMS) resonator with a signal associated with a communication band, wherein the DMS resonator includes: a piezoelectric material, a first reflector disposed above the piezoelectric material, a second reflector disposed above the piezoelectric material, and a plurality of interdigital transducers (IDTs) disposed above the piezoelectric material and positioned between the first and second reflectors, wherein the pitch of the electrode fingers in the first and second reflectors is greater than the pitch of the electrode fingers in the plurality of interdigital transducers, wherein the pitch variation of the electrode fingers in the plurality of interdigital transducers is less than 3% across the plurality of interdigital transducers, wherein the input node is connected to a first bus of a first subset of the plurality of IDTs, and wherein a second bus opposite to the first bus of the first subset of the plurality of IDTs is connected to a reference node.

[0104] At box 904, the method includes filtering the signal using multiple IDTs to generate a filtered signal.

[0105] At block 906, the method includes outputting a filtered signal at the output node of the DMS resonator, wherein the output node is connected to a first bus of a second subset of the plurality of IDTs, wherein a second bus opposite to the first bus of the second subset of the plurality of IDTs is connected to a reference node, and wherein each IDT in the first subset of IDTs is adjacent to an IDT in the second subset of IDTs.

[0106] As mentioned above, conventional DMS resonators are highly asynchronous, which can cause strong spurious peaks in the passband of filters designed using conventional DMS resonators. The aspects described herein reduce or eliminate cavity resonances occurring between IDTs in conventional DMS resonators using the above design configurations, while maintaining the benefits of cascaded IDT topologies of DMS resonators, which enable a variety of transverse electrical modes (e.g., compared to non-DMS single-IDT SAW resonators).

[0107] The aspects described herein improve the operation of DMS resonators and devices using SAW resonators through improved spurious (e.g., parasitic) mode suppression, improved manufacturability associated with SiO2 gap-filling limitations (e.g., achieving certain frequency bands without finger pitch causing SiO2 gap-filling problems related to manufacturability), and reduced size compared to conventional DMS designs. In particular, size benefits are possible due to the difficulty of using high-connectivity substrates with conventional DMS resonators, where near-synchronous DMS resonators according to the aspects described herein can use high-connectivity substrates, allowing for smaller dimensions and, for example, the removal of at least one step in the device design (e.g., as...). Figure 10In addition, in some aspects, low (e.g., constant or near constant) pitch variation allows for improved linearity of power variation when compared to conventional DMS resonators, which have poor power / linearity performance due to the asynchronous structure of low pitch (e.g., abutting fingers) in the IDT transition region between adjacent IDTs. Aspects described herein can include potential tradeoffs associated with slightly lower maximum achievable bandwidth, higher impedance for designs with fewer IDTs per resonator, and slightly higher insertion loss, which can be compensated as part of the device design.

[0108] Figure 10 is a schematic representation of an example filter 1000 according to aspects described herein, which can employ DMS resonators configured for near-synchronous operation. In particular, filter 1000 includes a ladder arrangement of acoustic SAW resonators Rs, Rp, where Rs is a series resonator and Rp is a shunt resonator. DMS resonators configured for near-synchronous operation can be used for at least one of the acoustic SAW resonators Rs, Rp of filter 1000.

[0109] The ladder structure of filter 1000 includes a plurality of basic sections. Each basic section includes at least one series resonator Rs and at least one shunt resonator Rp. The number of basic sections required to achieve a desired selectivity are connected together in series. Series resonators Rs belonging to adjacent basic sections can be combined as a common series resonator Rs, and shunt resonators Rp can also be combined if directly adjacent and belonging to different basic sections. One basic section provides a basic filter. More basic sections can be added to provide sufficient selectivity associated with the particular resonators used in that section.

[0110] Figure 11is a functional block diagram of at least a portion of an example of a simplified wireless transceiver circuit 1100 in which a DMS resonator configured for near-synchronous operation as described herein can be employed. The transceiver circuit 1100 is configured to receive signals / information for transmission (shown as I and Q values) that are provided to one or more baseband filters 1112. The filtered outputs are provided to one or more mixers 1114. The outputs from the one or more mixers 1114 are provided to a driver amplifier 1116, the output of which is provided to a power amplifier 1118 to produce an amplified signal for transmission. The amplified signal is output through one or more filters 1120 (e.g., a duplexer if used as a frequency division duplex transceiver or other filter) to an antenna 1122. The one or more filters 1120 can include the disclosed DMS resonator. The antenna 1122 can be used for both wirelessly transmitting data and receiving data. The transceiver circuit 1100 includes the following receive path: through the one or more filters 1120 to provide to a low noise amplifier (LNA) 1124 and further filter 1126, and then through one or more mixer circuits 1128 to down-convert from a receive frequency to a baseband frequency before the signal is further processed (e.g., provided to an analog-to-digital converter and then demodulated or otherwise processed in the digital domain). There can be separate filters for the receive circuit that can be implemented using the disclosed DMS resonator (e.g., the receive circuit can have a separate antenna or have a separate receive filter).

[0111] Figure 12 is a diagram of an environment 1200 including an electronic device 1202 that includes a wireless transceiver 1296, such as Figure 11 transceiver circuit 1100. In some aspects, the electronic device 1202 includes a display screen 1299 that can be used to display information associated with data transmitted via the wireless link 1206 and processed using components of the electronic device 1202 described below. Other aspects of an electronic device for multi-band communication using low phase delay filters in accordance with aspects described herein can not be configured with a display screen. In the environment 1200, the electronic device 1202 communicates with a base station 1204 over a wireless link 1206. As shown, the electronic device 1202 is depicted as a smartphone. However, the electronic device 1202 can be implemented as any suitable computing electronic device or other electronic device, such as a cellular base station, a broadband router, an access point, a cellular or mobile phone, a gaming device, a navigation device, a media device, a laptop computer, a desktop computer, a tablet computer, a server computer, a network attached storage (NAS) device, a smart appliance, an automobile including a vehicle-based communication system, an Internet of Things (IoT) device, a sensor or security device, an asset tracker, etc.

[0112] The base station 1204 communicates with the electronic device 1202 via a wireless link 1206, which can be implemented as any suitable type of wireless link. Although depicted as a base station tower of a cellular radio network, the base station 1204 can represent or be implemented as another device, such as a satellite, a terrestrial broadcast tower, an access point, a peer-to-peer device, a mesh network node, a fiber optic line, another electronic device substantially as described above, etc. Thus, the electronic device 1202 can communicate with the base station 1204 or another device via a wired connection, a wireless connection, or a combination thereof. The wireless link 1206 can include a downlink of data or control information communicated from the base station 1204 to the electronic device 1202, and an uplink of other data or control information communicated from the electronic device 1202 to the base station 1204. The wireless link 1206 can be implemented using any suitable communication protocol or standard, such as Third Generation Partnership Project Long Term Evolution (3GPP LTE, 3GPP NR 5G), IEEE 802.11, IEEE 802.16, Bluetooth ™

[0113] The electronic device 1202 includes a processor 1280 and a memory 1282. The memory 1282 can be part of or form part of a computer-readable storage medium. The processor 1280 can include any type of processor configured to execute processor-executable instructions (e.g., code) stored by the memory 1282, such as an application processor or a multi-core processor. The memory 1282 can include any suitable type of data storage media, such as volatile memory (e.g., random access memory (RAM)), non-volatile memory (e.g., flash memory), optical media, magnetic media (e.g., disk or tape), etc. In the context of the present disclosure, the memory 1282 is implemented to store instructions 1284, data 1286, and other information of the electronic device 1202, and thus the memory 1282 does not include transitory propagating signals or carrier waves when configured as or part of a computer-readable storage medium.

[0114] The electronic device 1202 can also include an input / output port 1290. The I / O port 1290 enables data exchange or interaction between elements of the device, other devices, networks, or users.

[0115] The electronic device 1202 can also include a signal processor (SP) 1292 (e.g., such as a digital signal processor (DSP)). The signal processor 1292 can function similarly to the processor and can be capable of executing instructions and / or processing information in conjunction with the memory 1282.

[0116] ​For communication purposes, the electronic device 1202 also includes a modem 1294, a wireless transceiver 1296, and an antenna (not shown). The wireless transceiver 1296 provides connectivity to respective networks and other electronic devices connected with those respective networks using radio-frequency (RF) wireless signals, and can include Figure 11 transceiver circuitry 1100. The wireless transceiver 1296 can facilitate communication over any suitable type of wireless network, such as a wireless local area network (WLAN), a peer-to-peer (P2P) network, a mesh network, a cellular network, a wireless wide area network (WW AN), a navigation network (e.g., the Global Positioning System (GPS) of North America or another Global Navigation Satellite System (GNSS)), and / or a wireless personal area network (WPAN).

[0117] The various operations of methods described above can be performed by any suitable means depending on the functionality of the means. This means can include various hardware and / or software component(s) and / or module(s), including, but not limited to a circuit, an application specific integrated circuit (ASIC), or processor. The means can be implemented as any form of hardware and / or software configured to perform the corresponding functions.

[0118] In an aspect, elements, or any portion thereof, of the systems and methods described herein can be implemented as a "processing system" that includes one or more processors. Aspects of the processor include microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, systems on a chip (SoC), baseband processors, field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. One or more processors in the processing system can execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

[0119] Accordingly, in one or more aspects embodiments, functions or circuitry blocks can be implemented in hardware, software, or any combination thereof. If implemented in software, the functions can be stored on or encoded as one or more instructions or code on a computer-readable medium. Computer-readable media includes computer storage media. Storage media can be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise a random-access memory (RAM), a read-only memory (ROM), an electrically erasable programmable ROM (EEPROM), compact disk ROM (CD-ROM) or other optical disk storage, magnetic disk storage or other magnetic storage devices, combinations of the aforementioned types of computer-readable media, or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer. In some aspects, components described in circuitry can be implemented by hardware, software, or any combination thereof.

[0120] The phrases "coupled to" and "coupled with" refer to any component being directly or indirectly physically connected to another component and / or any component being directly or indirectly in communication with another component (e.g., connected to another component through a wired or wireless connection and / or other suitable communication interface).

[0121] Generally, where there are operations illustrated in the figures, those operations can have corresponding counterpart components with similar numbering.

[0122] As used herein, the term "determining" encompasses a wide variety of actions. For example, "determining" can include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, a database or another data structure), ascertaining and the like. Also, "determining" can include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory) and the like. Also, "determining" can include resolving, selecting, choosing, establishing and the like.

[0123] The methods disclosed herein comprise one or more steps or actions for achieving the described method. The method steps and / or actions can be interchanged with one another without departing from the scope of the claims. In other words, unless a specific order of steps or actions is specified, the order and / or use of specific steps and / or actions can be modified without departing from the scope of the claims.

[0124] It is to be understood that the claims are not limited to the precise configuration and components illustrated above. Various modifications, changes, and variations can be made in the arrangement, operation, and details of the methods and apparatus described above without departing from the scope of the claims.

[0125] Claim language or other language reciting “at least one of’ and / or “one or more of’ a set indicates that one member of the set or multiple members of the set (in any combination) satisfy the claim. For example, claim language reciting “at least one of A and B” or “at least one of A or B” means A, B, or A and B. In another example, claim language reciting “at least one of A, B, and C” or “at least one of A, B, or C” means A, B, C, or A and B or A and C or B and C, A and B and C, or any repetition of information or data (e.g., A and A, B and B, C and C, A and A and B, etc.), or any other ordering, repetition, or combination of A, B, and C. The language “at least one of’ and / or “one or more of’ a set does not limit the set to the items listed in the set. For example, claim language reciting “at least one of A and B” or “at least one of A or B” can mean A, B, or A and B, and can additionally include items not listed in the set of A and B. The phrases “at least one” and “one or more” are used interchangeably herein.

[0126] Claim language or other language reciting “at least one processor configured to,” “at least one processor configured to,” “one or more processors configured to,” “one or more processors configured to,” and the like indicates that one processor or multiple processors (in any combination) can perform the associated operations. For example, claim language reciting “at least one processor configured to: X, Y, and Z” means a single processor can be used to perform operations X, Y, and Z; or multiple processors each tasked with the responsibility of a particular subset of operations X, Y, and Z, such that the multiple processors together perform X, Y, and Z; or a group of multiple processors working together to perform operations X, Y, and Z. In another example, claim language reciting “at least one processor configured to: X, Y, and Z” can mean that any single processor can perform only at least a subset of operations X, Y, and Z.

[0127] Where reference is made to one or more elements performing one or more functions, one element can perform the functions, or more than one element can perform the functions collectively. Where reference is made to one or more elements being configured to cause another element (e.g., a device) to perform a function, one element can be configured to cause the other element to perform all of the functions, or more than one element can be collectively configured to cause the other element to perform the functions.

[0128] Where reference is made to an entity (e.g., any entity or device described herein) performing or being configured to perform a function (e.g., a step of a method), the entity can be configured to cause one or more elements (either individually or collectively) to perform the function. One or more components of the entity can include at least one memory, at least one processor, at least one communication interface, another component configured to perform one or more (or all) of the functions, and / or any combination thereof. Where reference is made to an entity performing a function, the entity can be configured to cause one component to perform all of the functions, or more than one component collectively to perform the functions. Where the entity is configured to cause more than one component collectively to perform the functions, each function can not need to be performed by each of those components (e.g., different functions can be performed by different components), and / or each function can not need to be performed solely by one component (e.g., different components can perform different sub-functions of the function).

[0129] The following are a set of non-limiting aspects according to the details provided herein:

[0130] Aspect 1. An apparatus comprising: a dual-mode surface acoustic wave (DMS) resonator comprising: a piezoelectric material; a first interdigital transducer (IDT) disposed over a surface of the piezoelectric material, the first IDT comprising: a first busbar; a second busbar parallel to the first busbar; and a first plurality of IDT electrode fingers in an interdigital configuration, the first plurality of IDT electrode fingers comprising first IDT electrode fingers extending from the first busbar toward the second busbar and second IDT electrode fingers extending from the second busbar toward the first busbar; and a second IDT disposed adjacent to the first IDT over the surface of the piezoelectric material along an interface region between the first IDT and the second IDT, the second IDT comprising: a third busbar; a fourth busbar parallel to the third busbar; and a second plurality of IDT electrode fingers in the interdigital configuration, the second plurality of IDT electrode fingers comprising third IDT electrode fingers extending from the third busbar toward the fourth busbar and fourth IDT electrode fingers extending from the fourth busbar toward the third busbar; wherein the first IDT and the second IDT each comprise a transition region comprising five or fewer electrode fingers closest to the interface region, and wherein a chirp variation in the transition region is non-zero, and wherein the chirp variation in the transition region is less than plus or minus three percent.

[0131] Aspect 2. The apparatus of aspect 1, wherein the five or fewer electrode fingers have a transition area metallization ratio that is lower or greater than a metallization ratio of electrode fingers of the first IDT and the second IDT outside of the transition region.

[0132] Aspect 3. The apparatus of aspect 2, wherein the transition area metallization ratio is less than the metallization ratio of the electrode fingers outside of the transition region by less than fifteen percent.

[0133] Aspect 4. The apparatus of any one of aspects 1-3, wherein: the first plurality of IDT electrode fingers consists of 7-15 electrode fingers; and the second plurality of IDT electrode fingers consists of 7-15 electrode fingers.

[0134] Aspect 5. The apparatus of any one of aspects 1-4, wherein an electroacoustic cavity resonance around a first interface region between the first IDT and the second IDT is below a threshold to limit local energy in the transition region.

[0135] Aspect 6. The apparatus of Aspect 5, wherein the threshold is set to limit a local energy in the transition region, and allow a continuous power level of 24 decibels (dBm) or greater in the apparatus.

[0136] Aspect 7. The apparatus of any one of Aspects 1-6, wherein a level of self- harmonic generation power in the apparatus is comparable to a level of self-harmonic generation power using a pure ladder section of the same stack with comparable insertion loss and attenuation performance.

[0137] Aspect 8. The apparatus of any one of Aspects 1-7, wherein a second mode of the DMS resonator is defined by a distance between the first IDT reflector and the second IDT reflector.

[0138] Aspect 9. The apparatus of any one of Aspects 1-8, further comprising: a first IDT reflector; a second IDT reflector, wherein the first IDT and the second IDT are disposed between the first IDT reflector and the second IDT reflector.

[0139] Aspect 10. The apparatus of Aspect 9, wherein a passband of a filter formed by the DMS resonator is formed substantially based on acoustic waves formed by the second mode between the first IDT reflector and the second IDT reflector.

[0140] Aspect 11. The apparatus of any one of Aspects 1-10, wherein a passband of a filter formed by the DMS resonator is formed substantially based on acoustic waves formed by the first mode and the second mode.

[0141] Aspect 12. The apparatus of any one of Aspects 1-11, further comprising a third IDT adjacent to the second IDT on an opposite side from the first IDT.

[0142] Aspect 13. The apparatus of any one of Aspects 1-12, further comprising a plurality of additional IDTs positioned with their busbars along a line shared with busbars of the first IDT and the second IDT, wherein each IDT of the plurality of additional IDTs is adjacent to at least one adjacent IDT.

[0143] Aspect 14. The apparatus of Aspect 13, wherein a first busbar of each additional IDT of the plurality of additional IDTs is coupled to a reference node; and wherein a second busbar of each additional IDT of the plurality of additional IDTs is coupled to an input node or an output node.

[0144] Aspect 15. The apparatus of Aspect 13, wherein the bus bars of the plurality of additional IDTs coupled to the input node are adjacent to the bus bars of the plurality of additional IDTs coupled to the reference node; and wherein the bus bars of the plurality of additional IDTs coupled to the output node are adjacent to the bus bars of the plurality of additional IDTs coupled to the reference node.

[0145] Aspect 16. The apparatus of Aspect 13, wherein the bus bars of the plurality of additional IDTs coupled to the input node are adjacent to the bus bars of the plurality of additional IDTs coupled to the output node; and wherein the bus bars of the plurality of additional IDTs coupled to the reference node are adjacent to the bus bars of the plurality of additional IDTs coupled to the reference node.

[0146] Aspect 17. The apparatus of any one of Aspects 13 to 16, wherein the first IDT, the second IDT, and the plurality of additional IDTs are comprised of 15 or fewer IDTs.

[0147] Aspect 18. The apparatus of any one of Aspects 1 to 17, wherein each IDT of the DMS resonator has a different corresponding chirp configuration of electrode fingers than an adjacent IDT.

[0148] Aspect 19. The apparatus of any one of Aspects 1 to 18, wherein the DMS resonator is disposed in a first DMS resonator element having an input node connection and an output node connection for each IDT.

[0149] Aspect 20. The apparatus of Aspect 19, wherein at least a first output node of the first DMS resonator element is electrically coupled to at least a first input node of a second DMS resonator element as part of a DMS resonator image impedance circuit.

[0150] Aspect 21. The apparatus of any one of Aspects 18 to 20, wherein: the first DMS resonator element is associated with a different DMS resonator configuration than a DMS resonator configuration associated with the second DMS resonator element; and the DMS resonator configuration associated with the second DMS resonator element and the different DMS resonator configuration associated with the first DMS resonator element are configured for impedance matching having a near-zero susceptance at an inner reference plane connection between at least the first output node of the first DMS resonator element and at least the first input node of the second DMS resonator element.

[0151] Aspect 22. The apparatus of any one of aspects 19 through 21, wherein: at least the first output node of the first DMS resonator element and at least a first input node of the first DMS resonator element are coupled via a first capacitor; and at least the first input node of the second DMS resonator element and at least a first output node of the second DMS resonator element are coupled via a second capacitor.

[0152] Aspect 23. The apparatus of aspect 22, wherein the first capacitor has a capacitance value of 0 to 1 picofarad (pF), the capacitance value selected to fine tune a resonance frequency of a mode of the DMS resonator.

[0153] Aspect 24. The apparatus of any one of aspects 1 through 23, wherein the DMS resonator is used in a transmit filter of a wireless communication apparatus configured for power handling of at least 24 decibels (dBm).

[0154] Aspect 25. The apparatus of any one of aspects 1 through 24, wherein the DMS resonator is disposed in a filter of a wireless communication apparatus.

[0155] Aspect 26. An apparatus comprising: a dual-mode surface acoustic wave (DMS) resonator, the dual-mode surface acoustic wave (DMS) resonator comprising: a piezoelectric material; a first reflector disposed above the piezoelectric material; a second reflector disposed above the piezoelectric material; a plurality of interdigital transducers (IDTs) disposed above the piezoelectric material and positioned between the first reflector and the second reflector, wherein a magnitude of a pitch of electrode fingers in the first reflector and the second reflector is higher than a pitch of electrode fingers in the plurality of interdigital transducers, wherein a variation in the pitch of electrode fingers in the plurality of interdigital transducers is less than 3% across the plurality of interdigital transducers.

[0156] Aspect 27. The apparatus of aspect 26, wherein a metallization ratio of electrode fingers in a transition region formed by a subset of five or fewer fingers on either side of an adjacent IDT in the plurality of IDTs is greater than a metallization ratio of electrode fingers outside the transition region.

[0157] Aspect 28. An apparatus, the apparatus comprising: a dual-mode surface acoustic wave (DMS) resonator, the dual-mode surface acoustic wave (DMS) resonator comprising: a piezoelectric material; a first reflector disposed above the piezoelectric material; a second reflector disposed above the piezoelectric material; a plurality of interdigital transducers (IDTs) disposed above the piezoelectric material and positioned between the first reflector and the second reflector, wherein electrode fingers along the plurality of interdigital transducers are formed to have a pitch profile along the plurality of interdigital transducers that is opposite to formation of a cavity resonant mode between adjacent interdigital transducers of the plurality of transducers.

[0158] Aspect 29. The apparatus of aspect 28, wherein the pitch profile corresponds to a near constant pitch with a pitch variation along the plurality of interdigital transducers greater than zero and less than 3%.

[0159] Aspect 30. The apparatus of any one of aspects 1 to 29, wherein a magnitude of a pitch of the first reflector and the second reflector is greater than a magnitude of the pitch along the plurality of interdigital transducers.

[0160] Aspect 31. The apparatus of any one of aspects 1 to 30, wherein a metallization ratio of electrode fingers in a transition region formed by a subset of fingers on either side of an adjacent IDT is lower or greater than a metallization ratio of electrode fingers outside the transition region.

[0161] Aspect 32. A method comprising: exciting an input node of a dual-mode surface acoustic wave (DMS) resonator with a signal associated with a communication band, wherein the DMS resonator comprises: a piezoelectric material; a first reflector disposed above the piezoelectric material; a second reflector disposed above the piezoelectric material; and a plurality of interdigital transducers (IDTs) disposed above the piezoelectric material and positioned between the first reflector and the second reflector, wherein a magnitude of a pitch of electrode fingers in the first and second reflectors is higher than a pitch of electrode fingers in the plurality of IDTs, wherein a variation in the pitch of the electrode fingers in the plurality of IDTs is less than 3% across the plurality of IDTs, wherein the input node is coupled to a first busbar of a first subset of the plurality of IDTs, and wherein a second busbar opposite the first busbar of the first subset of the plurality of IDTs is coupled to a reference node; filtering the signal using the plurality of IDTs to generate a filtered signal; and outputting the filtered signal at an output node of DMS resonator, wherein the output node is coupled to a first busbar of a second subset of the plurality of IDTs, wherein a second busbar opposite the first busbar of the second subset of the plurality of IDTs is coupled to the reference node, and wherein each IDT in the first subset of IDTs is adjacent to an IDT in the second subset of IDTs.

[0162] Aspect 33. The method of aspect 32 is performed using any of the apparatuses of aspects 1-31 above.

Claims

1. An apparatus, the apparatus comprising: A dual-mode surface acoustic wave (DMS) resonator, the dual-mode surface acoustic wave (DMS) resonator comprising: piezoelectric materials; A first interdigital transducer (IDT) is disposed above the surface of the piezoelectric material, and the first IDT includes: First busbar; The second busbar is parallel to the first busbar; and A first plurality of IDT electrode fingers in an interdigitated configuration, the first plurality of IDT electrode fingers including a first IDT electrode finger extending from the first busbar toward the second busbar and a second IDT electrode finger extending from the second busbar toward the first busbar; and A second IDT, disposed adjacent to the first IDT and above the surface of the piezoelectric material along the interface region between the first IDT and the second IDT, comprises: Third busbar; A fourth busbar, which is parallel to the third busbar; and The second plurality of IDT electrode fingers are arranged in the interdigitated configuration, the second plurality of IDT electrode fingers including a third IDT electrode finger extending from the third busbar toward the fourth busbar and a fourth IDT electrode finger extending from the fourth busbar toward the third busbar; The first IDT and the second IDT each include a transition region, the transition region including five or fewer electrode fingers closest to the interface region, and wherein the chirp variation in the transition region is not zero, and wherein the chirp variation in the transition region is less than plus or minus three percent.

2. The apparatus of claim 1, wherein the five or fewer electrode fingers have a transition area metallization ratio that is lower than the metallization ratio of the electrode fingers outside the transition region of the first IDT and the second IDT.

3. The apparatus of claim 2, wherein the metallization ratio of the transition area is less than 15 percent of the metallization ratio of the electrode fingers outside the transition region.

4. The apparatus of claim 1, wherein the five or fewer electrode fingers have a transition area metallization ratio greater than the metallization ratio of the electrode fingers outside the transition region of the first IDT and the second IDT.

5. The apparatus according to claim 1, wherein: The first plurality of IDT electrode fingers are composed of 7 to 15 electrode fingers; and The second plurality of IDT electrode fingers consist of 7 to 15 electrode fingers.

6. The apparatus of claim 1, wherein the electroacoustic cavity resonance around the first interface region between the first IDT and the second IDT is below a threshold to limit local energy in the transition region.

7. The apparatus of claim 5, wherein the level of self-harmonic generation power in the apparatus is comparable to the level of self-harmonic generation power using a pure ladder segment of the same stack with comparable insertion loss and attenuation performance.

8. The apparatus according to claim 1, further comprising: First IDT reflector; A second IDT reflector, wherein the first IDT and the second IDT are disposed between the first IDT reflector and the second IDT reflector.

9. The apparatus of claim 8, wherein the second mode of the DMS resonator is defined by the distance between the first IDT reflector and the second IDT reflector.

10. The apparatus of claim 9, wherein the passband of the filter formed by the DMS resonator is substantially based on the acoustic wave formed by the second mode between the first IDT reflector and the second IDT reflector.

11. The apparatus of claim 10, wherein the passband of the filter formed by the DMS resonator is substantially based on the acoustic waves formed by the first mode and the second mode.

12. The apparatus of claim 1, further comprising a third IDT, the third IDT being adjacent to the second IDT on the opposite side from the first IDT.

13. The apparatus of claim 1, further comprising a plurality of additional IDTs positioned such that their busbars are along a line shared with the busbars of the first IDT and the second IDT, wherein each of the plurality of additional IDTs is adjacent to at least one adjacent IDT.

14. The apparatus of claim 13, wherein the first bus of each of the plurality of additional IDTs is connected to a reference node; and The second bus of each of the plurality of additional IDTs is connected to an input node or an output node.

15. The apparatus of claim 14, wherein the buses of the plurality of additional IDTs connected to the input node are adjacent to the buses of the plurality of additional IDTs connected to the reference node; and The buses of the plurality of additional IDTs connected to the output node are adjacent to the buses of the plurality of additional IDTs connected to the reference node.

16. The apparatus of claim 14, wherein the buses of the plurality of additional IDTs connected to the input node are adjacent to the buses of the plurality of additional IDTs connected to the output node; and The buses of the plurality of additional IDTs connected to the reference node are adjacent to the buses of the plurality of additional IDTs connected to the reference node.

17. The apparatus of claim 13, wherein the first IDT, the second IDT, and the plurality of additional IDTs comprise 15 or fewer IDTs.

18. The apparatus of claim 13, wherein each IDT of the DMS resonator has a corresponding chirped configuration different from that of the electrode fingers of the adjacent IDT.

19. The apparatus of claim 13, wherein the DMS resonator is disposed in a first DMS resonator element having input node connections and output node connections for each IDT.

20. The apparatus of claim 19, wherein at least a first output node of the first DMS resonator element is electrically connected to at least a first input node of the second DMS resonator element as part of a DMS resonator image impedance circuit.

21. The apparatus according to claim 20, wherein: The first DMS resonator element is associated with different DMS resonator configurations of the DMS resonator configuration associated with the second DMS resonator element; and The DMS resonator configuration associated with the second DMS resonator element and the different DMS resonator configurations associated with the first DMS resonator element are configured to have near-zero susceptance impedance matching at the inner reference plane connection between at least the first output node of the first DMS resonator element and at least the first input node of the second DMS resonator element.

22. The apparatus according to claim 20, wherein: At least the first output node of the first DMS resonator element and at least the first input node of the first DMS resonator element are connected via a first capacitor; and At least the first input node of the second DMS resonator element and at least the first output node of the second DMS resonator element are connected via a second capacitor.

23. The apparatus of claim 22, wherein the first capacitor has a capacitance value of 0 to 1 picofarad (pF), the capacitance value being selected to fine-tune the anti-resonant frequency of the mode of the DMS resonator.

24. The apparatus of claim 1, wherein the DMS resonator is used in a transmit filter of a wireless communication apparatus configured for power processing of at least 24 dBm.

25. An apparatus comprising: A dual-mode surface acoustic wave (DMS) resonator, the dual-mode surface acoustic wave (DMS) resonator comprising: piezoelectric materials; A first reflector is disposed above the piezoelectric material; A second reflector is disposed above the piezoelectric material; A plurality of interdigital transducers (IDTs) are disposed above the piezoelectric material and positioned between the first reflector and the second reflector, wherein the pitch of the electrode fingers in the first and second reflectors is greater than the pitch of the electrode fingers in the plurality of interdigital transducers, and the pitch variation of the electrode fingers in the plurality of interdigital transducers is less than 3% across the plurality of interdigital transducers.

26. The apparatus of claim 25, wherein the metallization ratio of the electrode fingers in the transition region formed by a subset of five or fewer fingers on any side of adjacent IDTs of the plurality of IDTs is greater than the metallization ratio of the electrode fingers outside the transition region.

27. An apparatus comprising: A dual-mode surface acoustic wave (DMS) resonator, the dual-mode surface acoustic wave (DMS) resonator comprising: piezoelectric materials; A first reflector is disposed above the piezoelectric material; A second reflector is disposed above the piezoelectric material; Multiple interdigital transducers (IDTs) are disposed above the piezoelectric material and positioned between the first reflector and the second reflector, wherein the electrode fingers along the multiple interdigital transducers are formed to have a pitch distribution along the multiple interdigital transducers, the pitch distribution being opposite to the formation of cavity resonant modes between adjacent interdigital transducers of the multiple transducers.

28. The apparatus of claim 27, wherein the pitch distribution corresponds to a near-constant pitch along the plurality of interdigital transducers with a pitch variation greater than zero and less than 3%.

29. The apparatus of claim 27, wherein the pitch of the first reflector and the second reflector is greater than the pitch along the plurality of interdigital transducers.

30. The apparatus of claim 27, wherein the metallization ratio of the electrode fingers in the transition region formed by a subset of the fingers on either side of adjacent IDTs of the plurality of IDTs is lower than or greater than the metallization ratio of the electrode fingers outside the transition region.

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