A method of designing an acoustic microwave filter in accordance with frequency response requirements comprises generating a modeled filter circuit design having a plurality of circuit elements comprising an acoustic resonant element defined by an electrical circuit model that comprises a parallel static branch, a parallel motional branch, and one or both of a parallel Bragg Band branch that models an upper Bragg Band discontinuity and a parallel bulk mode function that models an acoustic bulk mode loss. The method further comprises optimizing the modeled filter circuit design to generate an optimized filter circuit design, comparing a frequency response of the optimized filter circuit design to the frequency response requirements, and constructing the acoustic microwave filter from the optimized filter circuit design based on the comparison.

The present invention relates to a heterostructure, in particular, a piezoelectric structure, comprising a cover layer, in particular, a layer of piezoelectric material, the material of the cover layer having a first coefficient of thermal expansion, assembled to a support substrate, the support substrate having a second coefficient of thermal expansion substantially different from the first coefficient of thermal expansion, at an interface wherein the cover layer comprises at least a recess extending from the interface into the cover layer, and its method of fabrication.

The present invention relates to a heterostructure, in particular, a piezoelectric structure, comprising a cover layer, in particular, a layer of piezoelectric material, the material of the cover layer having a first coefficient of thermal expansion, assembled to a support substrate, the support substrate having a second coefficient of thermal expansion substantially different from the first coefficient of thermal expansion, at an interface wherein the cover layer comprises at least a recess extending from the interface into the cover layer, and its method of fabrication.

Provided are a surface acoustic wave device including IDT electrodes having an oxide electrode layer formed therein, and a method for fabricating the same. The surface acoustic wave device include a piezoelectric substrate and a plurality of IDT electrodes formed on the piezoelectric substrate, wherein each of the plurality of IDT electrodes includes: a main electrode layer formed on the upper surface of the piezoelectric substrate; an upper electrode layer formed on the main electrode layer; and an oxide electrode layer formed on the upper surface of the upper electrode layer by oxidation of the upper electrode layer, and wherein the thickness (t.sub.e) of each of the plurality of IDT electrodes satisfies 0.011t.sub.o/t.sub.e0.333 with respect to the thickness (t.sub.o) of the oxide electrode layer.

Provided are a surface acoustic wave device including IDT electrodes having an oxide electrode layer formed therein, and a method for fabricating the same. The surface acoustic wave device include a piezoelectric substrate and a plurality of IDT electrodes formed on the piezoelectric substrate, wherein each of the plurality of IDT electrodes includes: a main electrode layer formed on the upper surface of the piezoelectric substrate; an upper electrode layer formed on the main electrode layer; and an oxide electrode layer formed on the upper surface of the upper electrode layer by oxidation of the upper electrode layer, and wherein the thickness (t.sub.e) of each of the plurality of IDT electrodes satisfies 0.011t.sub.o/t.sub.e0.333 with respect to the thickness (t.sub.o) of the oxide electrode layer.

A substrate for a surface acoustic wave device or bulk acoustic wave device, comprising a support substrate and an piezoelectric layer on the support substrate, wherein the support substrate comprises a semiconductor layer on a stiffening substrate having a coefficient of thermal expansion that is closer to the coefficient of thermal expansion of the material of the piezoelectric layer than that of silicon, the semiconductor layer being arranged between the piezoelectric layer and the stiffening substrate.

A substrate for a surface acoustic wave device or bulk acoustic wave device, comprising a support substrate and an piezoelectric layer on the support substrate, wherein the support substrate comprises a semiconductor layer on a stiffening substrate having a coefficient of thermal expansion that is closer to the coefficient of thermal expansion of the material of the piezoelectric layer than that of silicon, the semiconductor layer being arranged between the piezoelectric layer and the stiffening substrate.

Aspects of this disclosure relate to an acoustic wave resonator with a patterned conductive layer. The acoustic wave resonator can include a piezoelectric layer, an interdigital transducer electrode over the piezoelectric layer, and a temperature compensation layer over the interdigital transducer electrode. The interdigital transducer electrode can include a bus bar and fingers extending from the bus bar. The fingers can each include an edge portion and a body portion. The patterned conductive layer can overlap the edge portions of the fingers. The patterned conductive layer can conductive portions that are spaced apart from each other. A portion of the temperature compensation layer can be positioned between the patterned conductive layer and the interdigital transducer electrode.

Aspects of this disclosure relate to an acoustic wave resonator with a patterned conductive layer. The acoustic wave resonator can include a piezoelectric layer, an interdigital transducer electrode over the piezoelectric layer, and a temperature compensation layer over the interdigital transducer electrode. The interdigital transducer electrode can include a bus bar and fingers extending from the bus bar. The fingers can each include an edge portion and a body portion. The patterned conductive layer can overlap the edge portions of the fingers. The patterned conductive layer can conductive portions that are spaced apart from each other. A portion of the temperature compensation layer can be positioned between the patterned conductive layer and the interdigital transducer electrode.

An elastic wave device includes a piezoelectric substrate and an interdigital transducer electrode disposed in a piezoelectric vibrating portion of the piezoelectric substrate to pass through the piezoelectric substrate.