Abstract: The present disclosure provides systems and methods for scalable and parallel computation of hierarchical cascading in finite element method (FEM) simulations of surface acoustic wave (SAW) devices. Different computing units of a cluster or cloud service may be assigned to independently model different core blocks or combinations of core blocks for iterative cascading to generate a model of the SAW devices. Similarly, frequency ranges may independently be assigned to computing units for modeling and analysis of devices, drastically speeding up computation.

Abstract: Acoustic resonator devices and filters. An acoustic resonator includes a substrate having a surface and a lithium niobate plate. A back surface of the lithium niobate plate is attached the substrate except for a portion of the lithium niobate plate forming a diaphragm that spans a cavity in the substrate. An interdigital transducer (IDT) is formed on a front surface of the lithium niobate plate such that interleaved fingers of the IDT are disposed on the diaphragm. The IDT and the lithium niobate plate configured such that a radio frequency signal applied to the IDT excites a shear primary acoustic mode within the diaphragm. Euler angles of the lithium niobate plate are [0°, ?, 0°], where ? is greater than or equal to 40° and less than or equal to 70°.

Abstract: A filter device has a substrate with a first cavity and a second cavity on a single die; and a bonding layer formed on the substrate but not spanning the first cavity or the second cavity. A piezoelectric plate is bonded to the bonding layer and spans the first and the second cavity. However, excess portions of piezoelectric plate are removed that extend a certain length past the perimeter of the first cavity and of the second cavity. Excess portions may be piezoelectric material that extends in the length and width direction past the perimeter of a cavity by more than between 2 and 25 percent of the cavity perimeter. An interdigital transducer (IDT) is on a front surface of the piezoelectric plate and having interleaved fingers over the first cavity.

Abstract: There are disclosed matrix filters having an input port and sub-filters connected between the input port and respective output ports. Each of the sub-filters includes a ladder circuit with n transversely-excited film bulk acoustic resonator (XBAR) series elements and n?1 capacitor shunt elements, where n, the order of the sub-filter, is an integer greater than 2. Each sub-filter further has a first switch in parallel with a first capacitor shunt element and a second switch in parallel with a last capacitor shunt element.

Abstract: Acoustic resonators are disclosed. An acoustic resonator includes a substrate having a surface and a single-crystal piezoelectric plate having front and back surfaces. The back surface is attached to the surface of the substrate except for a portion of the piezoelectric plate forming a diaphragm spanning a cavity in the substrate. An interdigital transducer (IDT) is formed on the front surface of the piezoelectric plate. The IDT includes: a first busbar and a second busbar disposed on respective portions of the piezoelectric plate other than the diaphragm; a first set of elongate fingers extending from the first bus bar onto the diaphragm; and a second set of elongate fingers extending from the second bus bar onto the diaphragm, the second set of elongate fingers interleaved with the first set of elongate fingers.

Abstract: Acoustic resonators and filter devices, and methods for making acoustic resonators and filter devices. An acoustic resonator includes a substrate having a surface and a single-crystal piezoelectric plate having front and back surfaces. The back surface is attached to the surface of the substrate except for a portion of the piezoelectric plate forming a diaphragm spanning a cavity in the substrate. A conductor pattern formed is formed on the front surface of the piezoelectric plate, including an interdigital transducer (IDT) with interleaved fingers of the IDT on the diaphragm. An insulating layer is formed between the piezoelectric plate and portions of the conductor pattern other than the interleaved fingers.

Abstract: A method of designing a filter to meet a set of specifications. The set of specifications is received, and a filter design is established. Analysis of the filter design is performed by: determining a part admittance matrix; determining a circuit admittance matrix based on the part admittance matrices; reducing interior nodes of the circuit admittance matrix; reducing algebraic nodes to transform the circuit admittance matrix into a Green's Function; evaluating the Green's Function to determine a circuit exterior node admittance matrix; and transforming the circuit exterior node admittance matrix to a circuit scattering matrix. The circuit scattering matrix is compared to the set of specifications to determine whether the filter design is satisfactory. When a determination is made that the design is not satisfactory, the filter design is modified and the process is repeated. When a determination is made that the design is satisfactory, a filter design description is output.

Abstract: There are disclosed acoustic resonators and methods of fabricating acoustic resonators. An acoustic resonator includes a piezoelectric plate having front and back surfaces, the back surface facing a substrate. A portion of the piezoelectric plate forms a diaphragm spanning a cavity in the substrate. A conductor pattern on the front surface includes a multi-pitch interdigital transducer (IDT) with interleaved fingers of the IDT on the diaphragm.

Abstract: There are disclosed acoustic filters and radios incorporating the acoustic filters. A filter includes a first filter port, a second filter port, and n sub-filters, where n is an integer greater than one. Each sub-filter has a first sub-filter port connected to the first filter port and a second sub-filter port connected to the second filter port. A first acoustic resonator is connected from the first filter port to ground, and a second acoustic resonator is connected from the second filter port to ground. The first and second acoustic resonators are configured to create respective transmission zeros adjacent to a lower edge of a passband of the filter.

Abstract: Radio frequency filters. A radio frequency filter includes a substrate attached to a piezoelectric plate, portions of the piezoelectric plate forming a plurality of diaphragms spanning respective cavities in the substrate. A conductor pattern formed on the piezoelectric plate includes a plurality of interdigital transducers (IDTs) of a respective plurality of resonators, interleaved fingers of each IDT disposed on a respective diaphragm of the plurality of diaphragms. The conductor pattern connects the plurality of resonators in a matrix filter circuit including a first sub-filter and a second sub-filter, each sub-filter comprising two or more resonators from the plurality of resonators.

Abstract: Acoustic resonators, acoustic filter devices and methods of making the same. An acoustic resonator device includes a piezoelectric plate having front and back surfaces, and an interdigital transducer (IDT) on the front surface including interleaved fingers. An overlapping distance of the interleaved fingers defines an aperture of the acoustic resonator device. The device further includes a fast region between the aperture and a busbar of the IDT. The piezoelectric plate and the IDT are configured such that a radio frequency signal applied to the IDT excites a primary shear acoustic mode having a first frequency in the piezoelectric plate within a central portion of the aperture and a primary shear acoustic mode having a second frequency in the fast region. The second frequency is higher than the first frequency.

Abstract: Filter devices. A first chip includes a first interdigital transducer (IDT) of a first acoustic resonator formed on a surface of a first piezoelectric wafer having a first thickness, interleaved fingers of the first IDT disposed on a portion of the first piezoelectric wafer spanning a first cavity in a first base. A second chip includes a second IDT of a second acoustic resonator formed on a surface of a second piezoelectric wafer having a second thickness less than the first thickness, interleaved fingers of the second IDT disposed on a portion of the second piezoelectric wafer spanning a second cavity in a second base. A circuit card coupled to the first chip and the second chip includes at least one conductor for making an electrical connection between the first IDT and the second IDT.

Abstract: Acoustic filters and methods of fabrication are disclosed. A filter device includes a substrate and a single-crystal piezoelectric plate, a back surface of the piezoelectric plate attached to a surface of the substrate. The filter device includes a plurality of acoustic resonators including one or more shunt resonators and one or more series resonators. Each of the plurality of acoustic resonators includes an interdigital transducer (IDT) formed on the front surface of the piezoelectric plate, interleaved fingers of the IDT disposed on a respective diaphragm formed by a respective portion of the piezoelectric plate that spans a respective cavity in the substrate. A divided frequency setting layer is formed on at least some of the one or more shunt resonators but not on the one or more series resonators.

Abstract: An acoustic resonator device includes a conductor pattern formed on a surface of a piezoelectric plate. The conductor pattern includes a first busbar, a second busbar, and n interleaved parallel fingers of an interdigital transducer (IDT), where n is a positive integer. The fingers extend alternately from the first and second busbars. A first finger and an n'th finger are at opposing ends of the IDT. The conductor pattern also includes a first reflector element proximate and parallel to the first finger and a second reflector element proximate and parallel to the n'th finger. A center-to-center distance pr between the first reflector element and the first finger and between the second reflector element and the n'th finger is greater than or equal to 1.2 times a pitch p of the IDT and less than or equal to 1.5 times the pitch p.

Abstract: Acoustic resonator devices and filters. An acoustic resonator includes a substrate and a lithium niobate plate. A back surface of the lithium niobate plate faces the substrate. A portion of the lithium niobate plate forms a diaphragm that spans a cavity in the substrate. An interdigital transducer (IDT) is on a front surface of the lithium niobate plate such that interleaved fingers of the IDT are on the diaphragm. The IDT and the lithium niobate plate are configured such that a radio frequency signal applied to the IDT excites a shear primary acoustic mode within the diaphragm. Euler angles of the lithium niobate plate are [0°, ?, 0° ], where ? is greater than or equal to 40° and less than or equal to 70°.

Abstract: Acoustic resonators and filters are disclosed. An acoustic resonator includes a substrate and a piezoelectric plate. A back surface of the piezoelectric plate is attached to the substrate except for a portion of the piezoelectric plate forming a diaphragm spanning a cavity in the substrate. A conductor pattern including an interdigital transducer (IDT) is formed on a front surface of the piezoelectric plate, interleaved fingers of the IDT disposed on the diaphragm. A front-side dielectric layer is formed on the front surface of the piezoelectric plate between, but not over, the IDT fingers. A back-side dielectric layer is formed on a back surface of the diaphragm. Thicknesses of the IDT fingers and the front-side dielectric layer are substantially equal. An acoustic impedance Zm of the IDT fingers and an acoustic impedance Zfd of the front-side dielectric layer satisfy the relationship 0.8Zm?Zfd?1.25Zm.

Abstract: There are disclosed acoustic resonators and radio frequency filter devices. A back surface of a single-crystal piezoelectric plate is attached to a surface of a substrate except for portions of the piezoelectric plate forming a plurality of diaphragms, each of which spans a respective cavity in the substrate. A conductor pattern is formed on the front surface, the conductor pattern including interdigital transducers (IDTs) of one or more pairs of sub-resonators, each pair consisting of two sub-resonators. The IDT of each sub-resonator includes interleaved fingers disposed on a respective diaphragm. The piezoelectric plate and the IDTs are configured such that respective radio frequency signals applied to each IDT excite respective shear primary acoustic modes in the respective diaphragms. The two sub-resonators of each pair of sub-resonators are positioned symmetrically about a central axis.

Abstract: Bandpass filters are disclosed. A bandpass filter includes a plurality of series resonators and a plurality of shunt resonators. The series resonators are connected in series between a first port and a second port. The plurality of series resonators includes a first series resonator and a second series resonator connected at a node. The plurality of shunt resonators includes a first shunt resonator coupled between the node and a ground. A capacitor bridges the first and second series resonators.

Abstract: Acoustic filters are disclosed. A bandpass filter has a passband between a lower band edge and an upper band edge. The bandpass filter includes a plurality of transversely-excited film bulk acoustic resonators (XBARs) connected in a ladder filter circuit. The plurality of XBARs includes at least one lithium tantalate XBAR and at least one lithium niobate XBAR.

Abstract: Acoustic sensor devices and sensor systems are disclosed. An acoustic sensor device includes a piezoelectric plate having a front surface and a back surface. A floating back-side conductor pattern is formed on the back surface. A first and second front-side conductor patterns are formed on a portion of the front surface opposite the back-side conductor pattern. A sensing layer is formed over all or a portion of the floating back-side conductor pattern.