Systems and methods for acoustic filters operating at high frequencies

Abstract

The present technology relates to systems and methods for acoustic filters operating at high frequencies. In an embodiment, the present technology provides a first resonator, a second resonator, and a third resonator. The first resonator includes a first layer coupled to and positioned between a first electrode and a second electrode. The second resonator is coupled to the first resonator at a first node. The third resonator is coupled to the first node and a ground terminal. The third resonator includes a second layer coupled to and positioned between a third electrode and a fourth electrode. Depending on embodiments, each resonator may be associated with one or more thickness extension (TE) modes and the device may function at low insertion loss over a high frequency range (e.g., greater than 5 GHz). Other embodiments are also present.

Description

Technical Field

[0001] The present technology relates to acoustic filter systems and methods of operating the same. Background Art

[0002] Acoustic filters, known for their ability to selectively transmit specific frequency ranges while attenuating other frequency ranges, have been used in a variety of applications ranging from audio systems to advanced communication devices. Over the past few decades, acoustic filters have been used in numerous systems such as radio frequency (RF) communication devices, mobile phones, and other electronic systems. However, as technological advancements continue and the demand for faster data transmission rates and wider bandwidths increases, there is a significant push to operate at much higher frequencies (e.g., greater than 5 GHz), which is becoming increasingly important for next generation communication systems, ultra-fast wireless data transmission, and applications in various emerging technologies.

[0003] Various approaches for advanced acoustic filter systems have been explored, but have proven to be inadequate.It is important to recognize the need for new and improved systems and methods for acoustic filters. Summary of the invention

[0004] In one aspect, the present disclosure provides an apparatus comprising: a first resonator comprising a first layer coupled to a first electrode and a second electrode and positioned between the first electrode and the second electrode, the first layer comprising a first piezoelectric material, the first resonator being associated with a first thickness extensional (TE) mode, the first TE mode comprising a TE n mode, wherein n is an integer greater than or equal to 2; a second resonator coupled to the first resonator at a first node; and a third resonator coupled to the first node and a first ground terminal, the third resonator comprising a second layer coupled to a third electrode and a fourth electrode and positioned between the third electrode and the fourth electrode, the second layer comprising a second piezoelectric material, the second resonator further comprising a third layer coupled to the third electrode.

[0005] In another aspect, the present disclosure provides a device comprising: a first resonator comprising a first layer coupled to a first electrode and a second electrode and positioned between the first electrode and the second electrode, the first layer comprising a first piezoelectric material, the first resonator being associated with a first thickness extensional (TE) mode; a second resonator coupled to the first resonator at a first node, the second resonator being associated with the first TE mode; a third resonator coupled to the first node and a first ground terminal, the third resonator being associated with a second TE mode; and a first filter coupled to the first resonator.

[0006] In another aspect, the present disclosure provides a device comprising: a first resonator comprising a first layer coupled to a first electrode and a second electrode and positioned between the first electrode and the second electrode, the first layer comprising a first piezoelectric material, the first resonator being associated with a first thickness extensional (TE) mode, the first TE mode being associated with a frequency of at least 5 GHz; a second resonator coupled to the first resonator at a first node, the second resonator being associated with the first TE mode; a third resonator coupled to the first node and a first ground terminal; and a fourth resonator coupled to the second resonator and a second ground terminal. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] A further understanding of the nature and advantages of particular embodiments may be achieved by reference to the remainder of the specification and drawings, wherein like reference numerals are used to refer to similar components. In some instances, a sub-label is associated with a reference numeral to represent one of multiple similar components. When a reference numeral is cited without elaborating on the existing sub-label, the reference numeral is intended to refer to all such multiple similar components.

[0008] Figure 1 is a schematic diagram illustrating an acoustic filter according to an embodiment of the present technology.

[0009] Figure 2 is a graph illustrating the frequency response of an acoustic resonator according to an embodiment of the present technology.

[0010] Figures 3A to 3E is a schematic cross-sectional view of a resonator of an acoustic filter according to an embodiment of the present technology.

[0011] Figures 4A to 4B is a diagram illustrating the frequency response of an acoustic filter according to an embodiment of the present technology.

[0012] Figure 5 is a schematic diagram illustrating an acoustic filter according to an embodiment of the present technology.

[0013] Figure 6 is a schematic diagram illustrating an acoustic filter according to an embodiment of the present technology.

[0014] Figure 7 is a schematic diagram illustrating an acoustic filter according to an embodiment of the present technology. DETAILED DESCRIPTION

[0015] The present technology relates to acoustic filter systems and methods. In an embodiment, the present technology provides a first resonator, a second resonator, and a third resonator. The first resonator includes a first layer coupled to a first electrode and a second electrode and positioned between the first electrode and the second electrode. The second resonator is coupled to the first resonator at a first node. The third resonator is coupled to the first node and a ground terminal. The third resonator includes a second layer coupled to a third electrode and a fourth electrode and positioned between the third electrode and the fourth electrode. Depending on the implementation, each resonator may be associated with one or more thickness extension (TE) modes and the device may function in a high frequency range (e.g., greater than 5 GHz) with low insertion loss. Other embodiments also exist.

[0016] Acoustic filters are important components in a wide range of applications including audio and communication devices, radar systems, medical imaging systems, satellite communication systems, and / or the like. The term "acoustic filter" may refer to a device capable of isolating and transmitting a specific range of frequencies. For example, an acoustic filter may be designed to selectively attenuate specific frequencies and allow other frequencies to pass relatively unattenuated. Acoustic filters operate by converting electrical signals applied to electrodes into acoustic waves in a resonator, which may include a layer of piezoelectric material coupled between two conductive plates (e.g., electrodes). Depending on the application, an acoustic filter may be designed to operate at a wide range of frequencies from a few kilohertz to several gigahertz.

[0017] As the demand for high frequency devices continues to grow, designing and manufacturing acoustic filters that operate at high frequencies (e.g., greater than 7 GHz) remains a challenging task. Various methods for implementing acoustic filters in the high frequency range involve operating the resonator in a specific TE mode, in which the resonator can undergo periodic expansion and contraction, resulting in the propagation of sound waves. The term "thickness extension mode" or "thickness extension mode" may refer to a type of vibration (e.g., along the thickness direction) that occurs in a resonator when the resonator is excited by an electrical signal. For example, a resonator can operate in a TE1 mode, in which the resonator exhibits a half-wavelength resonance. However, high frequency operation typically requires ultra-thin piezoelectric layers (e.g., less than 0.15um) and electrode layers (e.g., less than 0.06um), which not only leads to increased resistivity and limited resonator area, but also introduces manufacturing complexity and performance limitations, such as increased insertion loss and impaired electrostatic discharge (ESD) robustness.

[0018] In various embodiments, the present technology provides an acoustic filter capable of operating in a high frequency range (e.g., greater than 5 GHz). By employing higher order TE modes (e.g., TE2, TE3, etc.), embodiments of the present technology enable the construction of acoustic filters that balance key performance characteristics without sacrificing manufacturability or operational reliability. This approach allows the acoustic filter to operate with improved selectivity, reduced insertion loss, and enhanced ESD resilience, thereby meeting the needs of high frequency applications in a variety of operating settings.

[0019] The following description is presented to enable one skilled in the art to make and use the invention and to incorporate the invention into the context of a particular application. Various modifications and various uses in different applications will be readily apparent to one skilled in the art, and the general principles defined herein may be applied to a wide range of embodiments. Therefore, it is not intended that the present technology be limited to the embodiments presented, but rather that the present technology be given the widest scope consistent with the principles and novel features disclosed herein.

[0020] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present technology. However, it will be apparent to those skilled in the art that the present technology may be practiced without being limited to these specific details. In other instances, well-known structures and devices are shown in block diagram form rather than in detail in order to avoid obscuring the present technology.

[0021] The reader is advised to pay attention to all papers and documents which are filed concurrently with this specification and are available for public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference. Unless expressly stated otherwise, all features disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose. Therefore, unless expressly stated otherwise, each disclosed feature is only one example of a series of generic equivalent or similar features.

[0022] In addition, any element in the technical solution that does not explicitly state a "means" for performing a specified function or a "step" for performing a specified function should not be interpreted as a "means" or "step" clause as provided in 35 U.S.C. Section 112, paragraph 6. In particular, the use of "step" or "action" in the claims herein is not intended to refer to the provisions of 35 U.S.C. Section 112, paragraph 6.

[0023] When an element is referred to herein as being "connected" or "coupled" to another element, it is understood that the element may be directly connected to the other element, or that there may be intervening elements between the elements. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, it is understood that there are no intervening elements in the "direct" connection between the elements. However, the presence of a direct connection does not exclude other connections in which there may be intervening elements.

[0024] When an element is referred to herein as being "disposed" in some manner relative to another element (e.g., disposed on, between, below, near, or in some other relative manner), it is understood that the element may be disposed directly relative to the other element (e.g., disposed directly on the other element) or that there may be intervening elements between the elements. In contrast, when an element is referred to as being "directly disposed" relative to another element, it is understood that there are no intervening elements in the "direct" instance. However, the presence of a direct disposition does not exclude other instances in which there may be intervening elements.

[0025] Similarly, when an element is referred to herein as being "joined" to another element, it is understood that the element may be directly joined to the other element (without any intervening elements) or with intervening elements between the joined elements. In contrast, when an element is referred to as being "directly joined" to another element, it is understood that there are no intervening elements in the "direct" joining between the elements. However, the presence of direct joining does not exclude other forms of joining in which there may be intervening elements.

[0026] Likewise, when an element is referred to herein as a "layer," it is understood that the layer may be a single layer or may include multiple layers. For example, a conductive layer may include a plurality of different conductive materials or multiple layers of different conductive materials, and a dielectric layer may include a plurality of dielectric materials or multiple layers of dielectric materials. When a layer is described as being coupled or connected to another layer, it is understood that the coupled or connected layer may include intervening elements present between the coupled or connected layers. In contrast, when a layer is referred to as being "directly" connected or coupled to another layer, it is understood that there are no intervening elements between the layers. However, the presence of directly coupled or connected layers does not exclude other connections in which intervening elements may be present.

[0027] In addition, the terms left, right, front, back, top, bottom, forward, backward, clockwise and counterclockwise are used for explanation purposes only and are not limited to any fixed direction or orientation. Instead, the terms are only used to indicate the relative position and / or direction between the various parts of an object and / or component.

[0028] In addition, for ease of description, the methods and processes described herein may be described in a specific order. However, it should be understood that unless the context otherwise requires, the intervening process may occur before and / or after any portion of the described process, and other various procedures may be reordered, added, and / or omitted according to various embodiments.

[0029] Unless otherwise indicated, all numbers used herein to express quantities, sizes, etc. should be understood to be modified by the term "about" in all cases. In this application, unless otherwise specifically stated, the use of the singular includes the plural, and unless otherwise indicated, the use of the terms "and" and "or" means "and / or". In addition, the use of the terms "including" and "having" and other forms such as "includes", "included", "has", "have" and "had" should be considered non-exclusive. Moreover, unless otherwise specifically stated, terms such as "element" or "component" include both elements and components including one unit and elements and components including more than one unit.

[0030] As used herein, the phrase "at least one of..." preceding a series of items, with the terms "and" or "or" separating any of the items, modifies the entire list, rather than each member of the list (i.e., each item). The phrase "at least one of..." does not require selection of at least one of each of the listed items; rather, the phrase allows for a meaning that includes at least one of any of the items and / or at least one of any combination of the items. By way of example, the phrase "at least one of A, B, and C" or "at least one of A, B, or C" each refers to only A, only B, or only C; and / or any combination of A, B, and C. In instances where "at least one of each of A, B, and C" or, alternatively, "at least one of A, at least one of B, and at least one of C" is intended to be selected, it is expressly described as such.

[0031] One general aspect includes a device that includes a first resonator. The first resonator includes a first layer coupled to a first electrode and a second electrode and positioned between the first electrode and the second electrode. The first layer includes a first piezoelectric material. The first resonator is associated with a first thickness extensional (TE) mode, the first TE mode including a TE nThe device further comprises a first resonator coupled to the first resonator at the first node. The device further comprises a third resonator coupled to the first node and the first ground terminal. The third resonator comprises a second layer coupled to a third electrode and a fourth electrode and positioned between the third electrode and the fourth electrode. The second layer comprises a second piezoelectric material. The second resonator further comprises a third layer coupled to the third electrode.

[0032] Embodiments may include one or more of the following features. A first TE mode is associated with a frequency of at least 6 GHz. The third layer includes a mass load. The device further includes a filter coupled to the first resonator, the filter being configured to suppress the TE1 frequency. The first electrode and the second electrode are characterized by a thickness difference of at least 30%. The third electrode and the fourth electrode are characterized by a thickness difference of at least 30%. The third electrode and the fourth electrode are characterized by a thickness difference of less than 10%. The first electrode and the second electrode are characterized by a thickness difference of at least 150%, and the first TE mode includes a TE2 mode. The device further includes a fourth resonator coupled to the second resonator and the second ground terminal. The first resonator and the second resonator are associated with the first TE mode. The third resonator and the fourth resonator are associated with the second TE mode. The second TE mode may be different from the first TE mode. The second TE mode includes a TE1 mode. The device further includes a filter coupled to the first resonator, the filter being configured to suppress the TE1 frequency. The filter includes an inductor and a capacitor.

[0033] According to another embodiment, the present technology provides a device that includes a first resonator, the first resonator including a first layer coupled to a first electrode and a second electrode and positioned between the first electrode and the second electrode. The first layer includes a first piezoelectric material. The first resonator is associated with a first thickness extensional (TE) mode. The device further includes a second resonator coupled to the first resonator at a first node, the second resonator being associated with the first TE mode. The device further includes a third resonator coupled to the first node and a first ground terminal, the third resonator being associated with a second TE mode. The device further includes a first filter coupled to the first resonator.

[0034] Implementations may include one or more of the following features. The first resonator is configured in parallel with the third resonator. The device further includes a second filter coupled to the second resonator. The first filter is configured to suppress a third TE mode associated with the first resonator.

[0035] According to another embodiment, the present technology provides a device, the device including a first resonator, the first resonator including a first layer coupled to a first electrode and a second electrode and positioned between the first electrode and the second electrode. The first layer includes a first piezoelectric material. The first resonator is associated with a first thickness extensional (TE) mode, the first TE mode being associated with a frequency of at least 5 GHz. The device further includes a second resonator coupled to the first resonator at a first node, the second resonator being associated with the first TE mode. The device further includes a third resonator coupled to the first node and a first ground terminal. The device further includes a fourth resonator coupled to the second resonator and the second ground terminal.

[0036] Implementations may include one or more of the following features. A first resonator is configured in series with a second resonator. A third resonator and a fourth resonator are associated with a second TE mode, the second TE mode being different from the first TE mode.

[0037] Figure 1 is a schematic diagram illustrating an acoustic filter 100 according to an embodiment of the present technology. This figure provides examples only, which should not unduly limit the scope of the claims. Those skilled in the art will recognize many variations, alternatives, and modifications. Depending on the application, the acoustic filter 100 can be implemented as a bulk acoustic wave (BAW), a film bulk acoustic wave resonator (FBAR), and / or the like.

[0038] As an example, the acoustic filter 100 includes a first port 102 and a second port 104, which may be configured to receive an input or output signal (e.g., a radio frequency signal). The ports may be suitable for various applications, such as signal transmission or reception in a communication device. For example, the first port 102 may be a transmission port and the second port 104 may be an antenna port. In an example, the first port 102 may be a receiving port and the second port 104 may be an antenna port. For example, the acoustic filter 100 includes a resonator 106 (e.g., the first resonator described in technical solution 1). The term "resonator" may refer to an electronic component that exhibits resonance or resonant behavior when subjected to a specific frequency. Resonators can be used to generate and filter sound waves and may include, but are not limited to, piezoelectric crystal resonators, metal resonators, polymer resonators, and / or the like.

[0039] In various implementations, the resonator 106 may be associated with or operate in a first thickness extensional (TE) mode. For example, the term "thickness extensional mode" or "thickness extensibility mode" may refer to a type of vibration that occurs in a resonator (e.g., along the thickness direction) when the resonator is excited by an electrical signal. As an example, a TE mode is characterized by the number of nodes across the thickness of the resonator - the points where the displacement field is zero. For example, the TE1 mode is the lowest order TE mode and is characterized by one node in the strain field across the thickness of the resonator. In the TE1 mode, the resonator exhibits a half-wavelength resonance. In some cases, the TE1 mode - which may be referred to as the primary mode - defines the fundamental operating frequency of the resonator, where vibrations cause significant displacement of material at the top and bottom surfaces of the resonator, while the center (e.g., the center of gravity point along the thickness) remains relatively stationary.

[0040] In various examples, the TE2 mode is a second-order or second-highest-order (relative to TE1) TE mode. The TE2 mode is characterized by two nodes in the strain field across the thickness of the resonator. For example, operating in the TE2 mode, the resonator exhibits a full-wavelength resonance, with a full-wavelength fit between the top and bottom surfaces of the resonator. The TE2 mode may occur at a frequency higher than the frequency of the TE1 mode. The TE3 mode is characterized by three nodes in the strain field across the thickness of the resonator. It divides the resonator into three sections, each section exhibiting a half-wavelength resonance. For example, the TE3 mode will occur at a frequency higher than the frequency of the TE1 mode and the TE2 mode. As the complexity of the vibration pattern increases, it results in intricate waveforms and multiple minimum vibration nodes within the thickness of the resonator. The choice of the TE mode in which the resonator operates can directly affect the performance of the acoustic filter and its suitability for various applications. Each resonator can be configured to utilize one or more TE modes (e.g., TE1, TE2, TE3, etc.) for frequency filtering. Depending on the implementation, the TE mode first utilized may be greater than TE1 (e.g., TE2, TE3, etc.), thereby enabling the acoustic filter 100 to achieve high resonant frequencies (e.g., at least 5 GHz), reduced insertion loss, increased bandwidth, and enhanced selectivity. In some examples, the first TE mode is associated with a frequency of at least 6 GHz.

[0041] In some embodiments, the resonator 108 (e.g., the second resonator described in technical solution 1) may be coupled to the resonator 106 at a node 114 (e.g., the first node described in technical solution 1). For example, the term "node" may refer to a point for coupling two or more elements (e.g., a resonator, a resistor, a ground terminal, etc.). Two or more resonators may be coupled together directly or via a coupling component. For example, the resonator 108 may be associated with a first TE mode. In other words, the resonator 106 and the resonator 108 may be associated with the same TE mode (e.g., the first TE mode) or operate in the same TE mode. In some examples, the acoustic filter 100 further includes a resonator 110 (e.g., the third resonator described in technical solution 1) coupled to the node 114 and the ground terminal 112 (e.g., the first ground terminal described in technical solution 1). The term "ground terminal" or "ground" may refer to a reference point in a circuit where the voltage is considered to be zero. The resonator 110 may be associated with or operate in a second TE mode (eg, TE1, TE2, TE3, etc.) Depending on the implementation, the first TE mode and the second TE mode may be the same or different.

[0042] According to some embodiments, the acoustic filter 100 further includes a resonator 116 (e.g., the fourth resonator described in technical solution 9) coupled to the resonator 108 and a ground terminal 118 (e.g., the second ground terminal described in technical solution 9). For example, the resonator 116 can be coupled to the resonator 108 through the node 120. In various implementations, the acoustic filter 100 can be configured in a ladder topology, wherein a plurality of resonators are connected in a series-shunt configuration to achieve the desired filter characteristics. For example, the resonator 106 and the resonator 108 can be configured in series and can be referred to as a "series resonator". The resonator 110 and the resonator 116 can be configured in parallel and can be referred to as a "shunt resonator". In various implementations, the resonator 106 and the resonator 108 can be associated with a first TE mode (e.g., TE1) or operate in a first TE mode. The resonator 110 and the resonator 116 can be associated with a second TE mode or operate in a second TE mode. Depending on the implementation, the first TE mode and the second TE mode can be the same or different.

[0043] Depending on the application, the number and configuration of series and shunt resonators can be adjusted to achieve the desired operating frequency and filter characteristics. In addition, the resonant frequency of a resonator can be determined by its physical properties, such as its size, shape, and material composition. In some cases, achieving higher frequencies generally requires reducing the resonator size, which can introduce manufacturing complexity due to the precision required in making and aligning these smaller components. Therefore, the material properties and design configuration of the resonator can be optimized for achieving the desired frequency response while maintaining operating efficiency and cost effectiveness.

[0044] Figure 2 A graph 200 is provided illustrating the frequency response of an acoustic resonator according to an embodiment of the present technology. This figure merely provides an example, which should not unduly limit the scope of the claims. Those skilled in the art will recognize many variations, alternatives, and modifications. As an example, Figure 2 The diagram illustrates an acoustic resonator (e.g., Figure 1 Frequency response of the acoustic filter 100).

[0045] Depending on the implementation, the acoustic resonator can operate in various TE modes. For example, curve 202 illustrates the frequency response of an acoustic resonator operating in TE2 mode. As shown, curve 202 includes a first peak 204 at a resonant frequency f1 (e.g., greater than 6 GHz) and a second peak 206 at a resonant frequency f2 (e.g., greater than 12 GHz). In some examples, curve 210 illustrates the frequency response of an acoustic resonator operating in TE1 mode. Curve 210 may include a third peak 208 at a resonant frequency f3 (e.g., greater than 13 GHz). In high frequency applications (e.g., greater than 5 GHz), operating an acoustic filter in TE2, TE3, and higher modes provides several benefits over TE1 mode, including reduced ohmic losses, lower acoustic coupling, robust main modes, and reduced manufacturing complexity. This allows the acoustic filter to have improved ESD performance, power handling, and overall performance.

[0046] Figures 3A to 3E 300 is a cross-sectional schematic diagram of a resonator of an acoustic filter 300 according to an embodiment of the present technology. This figure provides examples only, which should not unduly limit the scope of the claims. Those skilled in the art will recognize many variations, alternatives, and modifications. In various embodiments, the resonator of the acoustic filter 300 can be implemented as an acoustic filter (e.g., Figure 1 One of the resonators of the acoustic filter 100).

[0047] like Figure 3AAs shown in , the acoustic filter 300 includes a resonator 314 (e.g., the first resonator described in technical solution 1), which may include a layer 302 coupled to a first electrode 304 and a second electrode 306 and / or positioned between the first electrode and the second electrode. The layer 302 may include a first piezoelectric material. The term "piezoelectric material" may refer to a material that generates an electric charge when subjected to mechanical stress or undergoes mechanical deformation when subjected to an electric field. The piezoelectric material may include, but is not limited to, quartz, lead zirconate titanate (PZT), lithium niobate (LiNbO3), aluminum nitride (AlN), aluminum scandium nitride (ASN), scandium nitride (ScN), zinc oxide (ZnO), lithium tantalate (LiTaO3), polyvinylidene fluoride (PVDF), and / or the like. Depending on the implementation, the layer 302 may be configured in a multilayer structure or a single layer structure. For example, the term "electrode" may refer to a conductor used to establish electrical contact with a non-metallic portion of a circuit. The electrodes can be used to apply an electric field to the piezoelectric material (e.g., layer 302), which can cause the piezoelectric material to deform and generate acoustic waves. The electrodes can be made of a variety of materials including, but not limited to, molybdenum, tungsten, aluminum, ruthenium, gold, silver, platinum, copper, conductive polymers, and / or the like. Depending on the implementation, the electrodes can be configured in a multi-layer structure or a single-layer structure.

[0048] In some embodiments, the acoustic filter 300 further includes a resonator 316 (e.g., the third resonator described in technical solution 1), which may include a layer 302 coupled to a third electrode 308 and a fourth electrode 310 and / or positioned between the third electrode and the fourth electrode. Layer 302 may include a second piezoelectric material. The first piezoelectric material and the second piezoelectric material may be the same or different. Depending on the implementation, resonator 314 and resonator 316 may share the same piezoelectric layer (e.g., layer 302) or have separate piezoelectric layers. In various examples, resonator 316 includes a layer 312 (e.g., the third layer described in technical solution 1) coupled to the third electrode 308. For example, layer 312 includes a mass load. For example, the term "mass loads" may refer to a material added to a resonator in order to change its resonant frequency. Mass loads can be used to tune a resonator to a specific frequency in order to generate multiple resonant frequencies required for a filter. The mass loading may include, but is not limited to, metal dots, polymer materials, dielectric materials, and / or the like.Depending on the implementation, layer 312 may have a thickness greater than or less than or equal to the thickness of third electrode 308 .

[0049] In various implementations, the resonant frequency of a resonator (e.g., resonators 314, 316) can be associated with the thickness of individual layers (e.g., electrodes, piezoelectric layers, mass loading, and / or the like). For high frequency applications, increasing the thickness of the electrodes and / or piezoelectric layers can enable the use of higher TE modes. This provides several advantages, including reducing electrode resistivity, increasing resonator area, and enhancing RF performance, resulting in a more reliable and efficient frequency response tailored for demanding applications. Depending on the application, the resonator can be configured in a symmetrical or asymmetrical structure. For example, Figure 3A The diagram illustrates the symmetrical structure of resonators 314 and 316. In resonator 314, the thickness of first electrode 304 can be substantially the same as the thickness of second electrode 306. In resonator 316, the thickness of third electrode 308 can be substantially the same as the thickness of fourth electrode 310. It should be understood that for the purposes of this disclosure, a thickness difference of less than 10% can be considered to be substantially the same. Depending on the implementation, first electrode 304 can have a thickness that is greater than, less than, or equal to the thickness of second electrode 306. In resonator 316, third electrode 308 and fourth electrode 310 can be characterized by a thickness difference of less than 10%. Depending on the implementation, third electrode 308 can have a thickness that is greater than, less than, or equal to the thickness of fourth electrode 310. In some cases, layer 312 can have a thickness that is greater than the thickness of third electrode 308.

[0050] In some embodiments, resonator 314 may be associated with or operate in a first TE mode; resonator 316 may be associated with or operate in a second TE mode. For example, resonator 314 may be a series resonator in acoustic filter 300; resonator 316 may be a shunt resonator in acoustic filter 300. The first TE mode may include TE n mode, where n is an integer greater than or equal to 2. In other words, the first TE mode can be a TE2 mode or higher. In an example, resonator 314 can operate in a TE2 mode, which is associated with a frequency of at least 6 GHz. For example, a 12 GHz operating frequency is used in various communication-related applications, and other operating frequencies are possible depending on the implementation. In some cases, resonator 316 can be associated with a TE n Mode associated or TE n The first TE mode and the second TE mode may be operated in a TE2 mode, wherein n is an integer greater than or equal to 2. In other words, the second TE mode may be a TE2 mode or a higher mode. In some cases, the resonator 316 may operate in a TE2 mode, which is associated with a frequency of at least 6 GHz. Depending on the application, the first TE mode and the second TE mode may be the same or different. For example, the first TE mode and the second TE mode may both be TE1 modes.

[0051] like Figure 3B As shown in , the second electrode 306 may have a thickness greater than the thickness of the first electrode 304. For example, the first electrode 304 and the second electrode 306 may be characterized by a thickness difference of at least 30%. For example, the thickness difference may be related to the acoustic impedance and / or conductivity of the electrode material. In some examples, the first electrode 304 and the second electrode 306 may be characterized by a thickness difference of at least 150%. In various embodiments, the third electrode 308 may have a thickness greater than the thickness of the fourth electrode 310. For example, the third electrode 308 and the fourth electrode 310 may be characterized by a thickness difference of at least 30%. In some examples, the third electrode 308 and the fourth electrode 310 may be characterized by a thickness difference of at least 150%. It should be understood that the thickness difference between the electrodes may result in an asymmetric configuration that allows the resonator (e.g., resonator 314, 316) to operate in a higher TE mode. Such a configuration is well suited to meet the needs of high frequency applications including 5G communications, automotive radar, medical imaging, and / or the like. For example, resonator 314 and resonator 316 can operate in TE2 mode or higher. Depending on the application, the first TE mode and the second TE mode can be the same or different. For example, the first TE mode and the second TE mode can both be TE2 modes. In some cases, layer 312 can be coupled to third electrode 308. Third electrode 308 can have a thickness greater than the thickness of layer 312.

[0052] like Figure 3C , the first electrode 304 may have a thickness greater than the thickness of the second electrode 306. For example, the first electrode 304 and the second electrode 306 may be characterized by a thickness difference of at least 30%. In some examples, the first electrode 304 and the second electrode 306 may be characterized by a thickness difference of at least 150%. In various embodiments, the fourth electrode 310 may have a thickness greater than the thickness of the third electrode 308. For example, the third electrode 308 and the fourth electrode 310 may be characterized by a thickness difference of at least 30%. In some examples, the third electrode 308 and the fourth electrode 310 may be characterized by a thickness difference of at least 150%. In various examples, the resonator 314 and the resonator 316 may operate in a TE2 mode or higher mode. Depending on the application, the first TE mode and the second TE mode may be the same or different. For example, the first TE mode and the second TE mode may both be TE2 modes. In some cases, the layer 312 may be coupled to the third electrode 308. The layer 312 may have a thickness greater than the thickness of the third electrode 308 .

[0053] In various embodiments, resonator 314 and resonator 316 may have different configurations. Figure 3DAs shown in , resonator 314 can be configured in an asymmetric structure and resonator 316 can be configured in a symmetric structure. For example, first resonator 304 can have a thickness greater than the thickness of second electrode 306. For example, first electrode 304 and second electrode 306 can be characterized by a thickness difference of at least 30%. In some examples, first electrode 304 and second electrode 306 can be characterized by a thickness difference of at least 150%. In resonator 316, the thickness of third electrode 308 can be substantially the same as the thickness of fourth electrode 310. In various examples, resonator 314 and resonator 316 can operate in TE2 mode or higher. In some cases, layer 312 can be coupled to third electrode 308. Layer 312 can have a thickness greater than the thickness of third electrode 308. Depending on the implementation, resonator 314 and resonator 316 can operate in different TE modes. In some examples, the first TE mode and the second TE mode can be associated with WiFi6 or WiFi7 filter responses. For example, resonator 314 may operate in TE2 mode or higher. Resonator 316 may operate in TE1 mode. By operating one or more resonators (e.g., resonators 314, 316) in different TE modes, acoustic filter 300 may process a wider range of frequencies, thereby effectively meeting various application requirements.

[0054] In various embodiments, such as Figure 3E , to facilitate operation in a higher TE mode, the thickness of one or more electrodes (e.g., first electrode 304, second electrode 306, third electrode 308, fourth electrode 310) may be increased. This enhanced thickness is used to accommodate specific mechanical and acoustic properties required for the resonator to operate in a higher TE mode. In some examples, resonator 314 and resonator 316 may operate in a TE3 mode or higher. In some cases, layer 312 may be coupled to third electrode 308. Layer 312 may have a thickness that is less than the thickness of third electrode 308.

[0055] Figures 4A to 4B 400 . The acoustic filter 400 may be implemented as a ladder filter (e.g., a sawtooth filter, a bulk acoustic wave filter, a Butterworth filter, an elliptical filter, and / or the like). For example, the acoustic filter 400 may be implemented as a ladder filter (e.g., Figure 1 Acoustic filter 100).

[0056] Depending on the application, the acoustic filter 400 may be optimized for operation in a high frequency band (eg, greater than 5 GHz). Figure 4A As shown in , the acoustic filter 400 exhibits low insertion loss (e.g., less than 1.5 dB) throughout its passband (e.g., 9 GHz to 9.15 GHz). The term "insertion loss" may refer to the amount of signal power loss or attenuation when a device or system is inserted into a transmission line. Insertion loss may be expressed in decibels (dB) and is calculated by comparing the power of the input signal to the power of the output signal after the filter. Low insertion loss (e.g., less than 1.5 dB) indicates that the acoustic filter 400 exhibits minimal attenuation, thereby ensuring that signals within the defined passband are transmitted with minimal amplitude reduction, thereby maintaining signal integrity and ensuring high efficiency.

[0057] In various embodiments, one or more resonators (e.g., series resonators or shunt resonators) can operate in a TE mode greater than TE1 (e.g., TE2 or higher modes). TE2 modes and higher TE modes have higher resonant frequencies than TE1 modes, thereby enabling the acoustic filter 400 to operate at higher frequencies. Figure 4B As shown in , when operating in TE1 mode, the acoustic filter 400 achieves a frequency of about 4 GHz. In contrast, when operating in TE2 mode, the acoustic filter 400 can achieve a frequency of about 9 GHz. The transition to the higher TE mode allows the use of thicker electrodes and piezoelectric materials compared to the TE1 main mode. For example, the resonator can be characterized by a thickness greater than 2 microns. The increased thickness contributes to a more robust structure, thereby minimizing the possibility of manufacturing defects and enhancing operational reliability. By operating in a higher TE mode, the acoustic filter 400 demonstrates enhanced signal quality, reduced insertion loss, and amplified resilience to environmental and operational stresses.

[0058] Figure 5 is a schematic diagram illustrating an acoustic filter 500 according to an embodiment of the present technology. This figure provides examples only, which should not unduly limit the scope of the claims. Those skilled in the art will recognize many variations, alternatives, and modifications. Depending on the application, the acoustic filter 500 can be implemented as a bulk acoustic wave (BAW), a film bulk acoustic resonator (FBAR), a filter, and / or the like.

[0059] As an example, the acoustic filter 500 includes a first port 502 and a second port 504, which may be configured to receive an input or output signal (e.g., a radio frequency signal). The ports may be suitable for various applications, such as signal transmission or reception in a communication device. The acoustic filter 500 may include one or more resonators. For example, the acoustic filter 500 includes at least one of a resonator 506, a resonator 508, a resonator 510, and a resonator 516. The resonator 506 may be associated with a first TE mode or operate in a first TE mode. The first TE mode may be greater than TE1. The resonator 508 may be coupled to the resonator 506 at a node 514. The resonator 508 may be associated with a first TE mode. In other words, the resonator 506 and the resonator 508 may be associated with the same TE mode (e.g., the first TE mode) or operate in the same TE mode. In some embodiments, the resonator 506 and the resonator 508 may be configured in series.

[0060] In various implementations, the resonator 510 may be coupled to a node 514 and a ground terminal 512. The resonator 510 may be associated with a second TE mode (e.g., TE1, TE2, TE3, etc.) or operate in a second TE mode. Depending on the implementation, the first TE mode and the second TE mode may be the same or different. According to some embodiments, the acoustic filter 500 further includes a resonator 516 coupled to the resonator 508 and the ground terminal 518. For example, the resonator 516 may be coupled to the resonator 508 via a node 520. In some embodiments, the resonator 510 and the resonator 516 may be configured in parallel. The resonator 516 may be associated with a second TE mode. In other words, the resonator 510 and the resonator 516 may be associated with the same TE mode (e.g., the second TE mode) or operate in the same TE mode.

[0061] In various embodiments, one or more resonators of the acoustic filter 500 can be operated in a high TE mode (e.g., TE2 or higher mode). However, one of the challenges of operating an acoustic filter in a high TE mode is the presence of lower order TE modes (e.g., TE1 modes), which can impair the performance of the filter by introducing undesirable signal interference and distortion. In various implementations, the acoustic filter 500 may further include a filter 522 configured to suppress and / or remove TE1 mode frequencies. For example, the filter 522 may be coupled to the resonator 506 and the ground terminal 524. The filter 522 may include an LC circuit, which may include an inductor 530 and a capacitor 532. Depending on the implementation, the inductor 530 and the capacitor 532 may be configured in series or in parallel. The term "inductor" may refer to an electronic component that stores energy in a magnetic field when current flows through it. An inductor may include, but is not limited to, a coil, a ceramic inductor, a chip inductor, and / or the like. The term "capacitor" may refer to an electronic component that stores energy in an electric field. The capacitor may include, but is not limited to, a ceramic capacitor, a film capacitor, an electrolytic capacitor, and / or the like. The LC circuit may resonate at a specific frequency, thereby isolating or attenuating unwanted signals at a specific frequency (e.g., the TE1 frequency). By strategically introducing LC resonance at the frequency of the main mode (e.g., the TE1 mode), unwanted modes may be significantly rejected. In some cases, the acoustic filter 500 may further include a filter 526 coupled to the resonator 508 and the ground terminal 528.

[0062] Figure 6 6 is a schematic diagram illustrating an acoustic filter 600 according to an embodiment of the present technology. This diagram only provides examples, which should not unduly limit the scope of the claims. Those skilled in the art will recognize many variations, alternatives, and modifications. The acoustic filter 600 may include at least one of a first port 602, a second port 604, a resonator 606, a resonator 608, a resonator 610, and a resonator 616. The resonator 606 may be associated with a first TE mode or operate in a first TE mode. The first TE mode may be greater than TE1. The resonator 608 may be coupled to the resonator 606 at a node 614. The resonator 608 may be associated with a first TE mode. In other words, the resonator 606 and the resonator 608 may be associated with the same TE mode (e.g., the first TE mode) or operate in the same TE mode. In some embodiments, the resonator 606 and the resonator 608 may be configured in series.

[0063] In various implementations, the resonator 610 may be coupled to a node 614 and a ground terminal 612. The resonator 610 may be associated with a second TE mode (e.g., TE1, TE2, TE3, etc.) or operate in a second TE mode. Depending on the implementation, the first TE mode and the second TE mode may be the same or different. According to some embodiments, the acoustic filter 600 further includes a resonator 616 coupled to the resonator 608 and the ground terminal 618. For example, the resonator 616 may be coupled to the resonator 608 via a node 620. In some embodiments, the resonator 610 and the resonator 616 may be configured in parallel. The resonator 616 may be associated with a second TE mode. In other words, the resonator 610 and the resonator 616 may be associated with the same TE mode (e.g., the second TE mode) or operate in the same TE mode.

[0064] In various embodiments, one or more resonators of the acoustic filter 600 can be operated in a high TE mode (e.g., TE2 or higher mode). However, one of the challenges of operating an acoustic filter in a high TE mode is the presence of a lower order TE mode (e.g., TE1 mode), which can impair the performance of the filter by introducing undesirable signal interference and distortion. In various implementations, the acoustic filter 600 may further include a filter 622, which is configured to suppress the TE1 mode and remove the TE1 frequency. For example, the filter 622 may be coupled to the resonator 606 and the ground terminal 624. The filter 522 may include a high pass circuit. The term "high pass circuit" may refer to a circuit that passes a signal having a frequency higher than a specific cutoff frequency and attenuates a signal having a frequency lower than the cutoff frequency. The high pass circuit may prevent the TE1 mode signal from passing through the filter, thereby effectively suppressing the TE1 mode during operation. Depending on the implementation, the filter 522 may include one or more components, including but not limited to resistors, capacitors, inductors, and / or the like. Depending on the frequency of the TE1 mode and the desired performance of the filter, one or more components of the filter 522 may be configured in series or in parallel. In some cases, the acoustic filter 600 may further include a filter 626 coupled to the resonator 608 and a ground terminal 628.

[0065] Figure 7is a schematic diagram illustrating an acoustic filter 700 according to an embodiment of the present technology. This diagram provides examples only, which should not unduly limit the scope of the claims. Those skilled in the art will recognize many variations, alternatives, and modifications. The acoustic filter 700 may include at least one of a first port 702, a second port 704, a resonator 706, a resonator 708, a resonator 710, and a resonator 716. For example, the first port 702 and the second port 704 may be configured to receive an input or output signal (e.g., a radio frequency signal). The ports may be suitable for various applications, such as signal transmission or reception in a communication device.

[0066] In various implementations, resonator 706 may be associated with or operate in a first TE mode. The first TE mode may be greater than TE1. Resonator 708 may be coupled to resonator 706 at node 714. Resonator 708 may be associated with a first TE mode. In other words, resonator 706 and resonator 708 may be associated with or operate in the same TE mode (e.g., the first TE mode). In some embodiments, resonator 706 and resonator 708 may be configured in series.

[0067] In various implementations, the resonator 710 may be connected to a node 714 and a ground terminal 712. The resonator 710 may be associated with a second TE mode (e.g., TE1, TE2, TE3, etc.) or operate in a second TE mode. Depending on the implementation, the first TE mode and the second TE mode may be the same or different. According to some embodiments, the acoustic filter 700 further includes a resonator 716 coupled to the resonator 708 and the ground terminal 718. For example, the resonator 716 may be coupled to the resonator 708 via a node 720. In some embodiments, the resonator 710 and the resonator 716 may be configured in parallel. The resonator 716 may be associated with a second TE mode. In other words, the resonator 710 and the resonator 716 may be associated with the same TE mode (e.g., the second TE mode) or operate in the same TE mode.

[0068] In various embodiments, one or more resonators of the acoustic filter 700 can be operated in a high TE mode (e.g., TE2 or higher mode). However, one of the challenges of operating an acoustic filter in a high TE mode is the presence of a lower order TE mode (e.g., TE1 mode), which can impair the performance of the filter by introducing undesirable signal interference and distortion. In various implementations, the acoustic filter 700 may further include an inductor 720 coupled to the resonator 710. The inductor 720 may be configured to adjust the resonant frequency of the capacitance of the resonator (e.g., resonator 710) to suppress the lower mode. For example, by adjusting the inductance value of the inductor 720, the resonant frequency can be shifted to the frequency of the TE1 mode. This can produce a notch in the filter frequency response at the TE1 frequency, thereby effectively suppressing the undesirable TE1 mode. In some cases, the acoustic filter 700 further includes an inductor 722 coupled to the resonator 722 and the ground terminal 718. Similar to inductor 720, inductor 722 may be configured to adjust the resonant frequency of a resonator (eg, resonator 716) to suppress the TE1 mode and the TE1 frequency.

[0069] Although specific embodiments have been fully described above, various modifications, alternative constructions and equivalents may be used. Therefore, the above description and illustrations should not be taken as limiting the scope of the present technology, which is defined by the appended claims.

Claims

1. A device comprising: A first resonator includes a first layer coupled to a first electrode and a second electrode and positioned between the first electrode and the second electrode, the first layer including a first piezoelectric material, the first resonator being associated with a first thickness extensional TE mode, the first TE mode including a TE n mode, where n is an integer greater than or equal to 2; a second resonator coupled to the first resonator at a first node; and a third resonator coupled to the first node and the first ground terminal, the third resonator comprising a second layer coupled to a third electrode and a fourth electrode and positioned between the third electrode and the fourth electrode, the second layer comprising a second piezoelectric material, the second resonator further comprising a third layer coupled to the third electrode. 2 . The apparatus of claim 1 , wherein the first TE mode is associated with a frequency of at least 6 GHz.

3. The device of claim 1, wherein the third layer comprises mass loading. 4 . The device of claim 1 , further comprising a filter coupled to the first resonator, the filter configured to suppress TE1 frequencies.

5. The device of claim 1, wherein the first electrode and the second electrode are characterized by a thickness difference of at least 30%.

6. The device of claim 1, wherein the third electrode and the fourth electrode are characterized by a thickness difference of at least 30%.

7. The device of claim 1, wherein the third electrode and the fourth electrode are characterized by a thickness difference of less than 10%.

8. The device of claim 1, wherein the first electrode and the second electrode are characterized by a thickness difference of at least 150%, and the first TE mode comprises a TE2 mode.

9. The device of claim 1, further comprising a fourth resonator coupled to the second resonator and a second ground terminal.

10. The device of claim 9, wherein the first and second resonators are associated with the first TE mode, and the third and fourth resonators are associated with a second TE mode, the second TE mode being different from the first TE mode. The apparatus of claim 10 , wherein the second TE mode comprises a TE1 mode.

12. The device of claim 1, further comprising a filter coupled to the first resonator, the filter configured to suppress TE1 frequencies.

13. The device of claim 12, wherein the filter comprises an inductor and a capacitor.

14. An apparatus comprising: a first resonator comprising a first layer coupled to a first electrode and a second electrode and positioned between the first electrode and the second electrode, the first layer comprising a first piezoelectric material, the first resonator being associated with a first thickness extensional TE mode; a second resonator coupled to the first resonator at a first node, the second resonator being associated with the first TE mode; a third resonator coupled to the first node and the first ground terminal, the third resonator being associated with a second TE mode; and A first filter is coupled to the first resonator.

15. The apparatus of claim 14, wherein the first resonator is configured in parallel with the third resonator.

16. The device of claim 14, further comprising a second filter coupled to the second resonator.

17. The device of claim 14, wherein the first filter is configured to suppress a third TE mode associated with the first resonator.

18. An apparatus comprising: a first resonator comprising a first layer coupled to a first electrode and a second electrode and positioned between the first electrode and the second electrode, the first layer comprising a first piezoelectric material, the first resonator being associated with a first thickness extensional TE mode, the first TE mode being associated with a frequency of at least 5 GHz; a second resonator coupled to the first resonator at a first node, the second resonator being associated with the first TE mode; a third resonator coupled to the first node and a first ground terminal; and A fourth resonator is coupled to the second resonator and a second ground terminal.

19. The apparatus of claim 18, wherein the first resonator is configured in series with the second resonator.

20. The device of claim 18, wherein the third resonator and the fourth resonator are associated with a second TE mode, the second TE mode being different from the first TE mode.

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