An acoustic resonator includes a piezoelectric thin film (PTF) disposed on a carrier substrate. The PTF confines a fundamental shear-horizontal (SH0) surface-acoustic wave (SAW) within the PTF. The acoustic resonator includes an input bus line coupled to an input source and a ground bus line coupled to a ground potential. The acoustic resonator includes a first grating reflector disposed at a first end of the PTF and coupled between the input bus line and the ground bus line. The acoustic resonator includes a second grating reflector disposed at a second end of the PTF and coupled between the input bus line and the ground bus line. The acoustic resonator includes interdigital transducers (IDTs) disposed between the first grating reflector and the second grating reflector. Each IDT includes an input electrode coupled to the input bus line, and a ground electrode coupled to the ground bus line.

An elastic wave device includes a multilayer body, an antenna terminal, a ground terminal, a signal terminal, an IDT electrode, and an insulating film. The multilayer body includes a support substrate and a piezoelectric film disposed on the support substrate. The antenna terminal is disposed on or above the support substrate. The ground terminal is directly disposed on the support substrate. The signal terminal is disposed above the support substrate. The IDT electrode is disposed on the piezoelectric film. The insulating film is disposed between the support substrate and the signal terminal. The multilayer body includes one of a layer made of a high acoustic-velocity material and an acoustic reflection layer.

An elastic wave element includes a piezoelectric substrate, an IDT electrode including a first comb-shaped electrode and a second comb-shaped electrode, and reflectors. Each of the reflectors includes a first reflective busbar electrode, a second reflective busbar electrode, and reflective electrode fingers. The first comb-shaped electrode includes a first busbar electrode connected to the first reflective busbar electrodes, and first electrode fingers. The second comb-shaped electrode includes a second busbar electrode and second electrode fingers. In in-between areas, in each of which a reflective electrode finger and a first electrode finger adjacent to each other in the elastic-wave propagation direction face each other, connecting electrodes which electrically couple the reflective electrode fingers to the first electrode fingers are provided.

This invention focuses on minimizing the hot spots on a filter chip by creating thermal radiators using the mechano-acoustic structures and connection circuitry. A gradual increase of metal to wafer relation is made to provide better heat dissipation and heat sinking. Preferably the shunt lines of the ladder type arrangement of SAW resonators (RS1, RS2, RS3) comprise a broadened section (BBCN). Each two series resonators (RS1, RS2, RS3) that are subsequent to each other in the series signal line are connected via a common busbar (BBCN) extending over a whole length of that subsequent series resonators, a lateral extension of the common busbars represents a first section of a respective shunt line each, each first shunt line section between a node and the parallel resonator (RP1, RP2) of a shunt line (SLS1) comprises a broadened section (BS) that is broader than the common busbar, the broadened section extends over the whole width of the parallel resonator (RP1), the first reflector (REF1) of the parallel resonator that faces the laterally adjacent series resonator is formed from the broadened section (BS).

An elastic wave apparatus includes a piezoelectric substrate and an IDT electrode. The IDT electrode includes a pair of busbars that face each other, electrode fingers, and dummy electrode fingers. At least the electrode fingers or the dummy electrode fingers each include a distal end having a width less than a width of another portion of the electrode finger or the dummy electrode finger including the distal end. A first straight line extending along a center or approximate center of one of the electrode fingers and a second straight line extending along a center or approximate center of one of the dummy electrode fingers facing the one of the electrode fingers are at different positions in an elastic wave propagation direction.

An elastic wave apparatus includes a piezoelectric substrate including a main surface and a polarization axis direction having a tilt angle with respect to the main surface, an IDT electrode provided on the main surface, and at least one line on the main surface and between an end edge of the main surface and the IDT electrode. A relationship a316|cos()|m is satisfied where a denotes a distance from the end edge of the main surface to the IDT electrode and b28 m where a dimension of the line along a direction connecting the end edge to the IDT electrode is defined as a width, b denotes the width of the line when one line is provided, and b denotes the sum of the widths of multiple lines when the multiple lines are provided.

To provide a method of producing a lithium niobate (LN) substrate which allows treatment conditions regarding a temperature, a time, and the like to be easily managed and in which an in-plane distribution of a volume resistance value is very small, and also variations in volume resistivity are small among substrates machined from the same ingot.

A method of producing an LN substrate by using an LN single crystal grown by the Czochralski process, in which a lithium niobate single crystal having a Fe concentration of 50 mass ppm or more and 2000 mass ppm or less in the single crystal and being in a form of an ingot is buried in an Al powder or a mixed powder of Al and Al.sub.2O.sub.3, and heat-treated at a temperature of 450 C. or more and less than 660 C., which is a melting point of aluminum, to produce a lithium niobate single crystal substrate having a volume resistivity controlled to be within a range of 110.sup.8 .Math.cm or more to 210.sup.12 .Math.cm or less.

A filter device includes a first filter chip including a first signal terminal and a second filter chip including a second signal terminal that are mounted above a package substrate including a substrate main body. First and second signal electrode pads are provided on a first main surface of the package substrate and are respectively joined to the first and second signal terminals. First and second outer terminals are provided on a second main surface 3b of the substrate main body. The first and second signal electrode pads and the first and second outer terminals are connected to each other with first and second wirings, respectively. The second outer terminal is located at the first signal electrode pad side and the first outer terminal is located at the second signal electrode pad side when seen from above.

An acoustic wave device includes: a substrate; a first acoustic wave resonator and a second acoustic wave resonator located on the substrate; a first wiring line electrically coupled to the first acoustic wave resonator, located on the substrate, and located between the first acoustic wave resonator and the second acoustic wave resonator; and a second wiring line electrically coupled to the second acoustic wave resonator, located on the substrate, located between the first acoustic wave resonator and the second acoustic wave resonator, having an electric potential different from an electric potential of the first wiring line, and having a thickness greater than a thickness of the first wiring line.

An elastic wave device includes a dielectric film on a piezoelectric substrate, an IDT electrode including first and second comb electrodes on the dielectric film, first and second wiring electrodes electrically connected to the first and second comb electrodes, wherein the first comb electrode and the second comb electrode each include electrode fingers and a busbar in contact with the electrode fingers. An electrical conductivity of the piezoelectric substrate is higher than the electrical conductivity of the dielectric film. At least one of the first wiring electrode, the second wiring electrode, the busbar of the first comb electrode, and the busbar of the second comb electrode includes a portion that is in direct contact with the piezoelectric substrate.