An elastic wave device includes a piezoelectric substrate, a first elastic wave element on the piezoelectric substrate and including at least one first interdigital transducer electrode and a first reflector in an area of the first interdigital transducer electrode at one side in a propagation direction of elastic waves, and a second elastic wave element on the piezoelectric substrate and including at least one second interdigital transducer electrode and a second reflector in an area of the second interdigital transducer electrode at one side in the propagation direction of elastic waves. The first and second reflectors are disposed side by side in the propagation direction. A reflection member, between the first and second reflectors, reflects elastic waves in at least a direction different from the propagation direction.

A micro-acoustic device comprises a confinement structure (CS) adapted to block propagation of acoustic waves of an acoustic wave resonator (TEL, PL, BEL; ES) at an operation frequency of the device to confine the acoustic waves to the acoustic path or the acoustic volume. It is proposed to use a phononic crystal material for producing the confinement structure.

A resonator device for measuring stress comprises at least two resonators, each resonator comprising an inter-digitated transducer structure arranged between two reflecting structures on or in a piezoelectric substrate, wherein the at least two resonators are arranged and positioned such that they have two different wave propagation directions, and each resonator comprises at least two parts with the area between the two parts of the at least two resonators forming a cavity, wherein the cavity is shared by the at least two resonators and wherein for at least one resonator, in particular, all resonators, the inter-digitated transducer structure comprises a first material and the reflecting structures a second material different from the first material and/or the inter-digitated transducer structure and the reflecting structures have different geometrical parameters. A differential sensing device comprises at least one resonator device as described herein.

An acoustic wave device includes first and second acoustic wave elements. The first acoustic wave element is disposed on a piezoelectric substrate, and includes at least one first IDT electrode. The second acoustic wave element is disposed on the piezoelectric substrate, and includes at least one second IDT electrode. The first and second acoustic wave elements are adjacent to each other in the direction of acoustic wave propagation. A diffracting component that diffracts an acoustic wave is disposed between the first IDT electrode and the second IDT electrode. The diffracting component includes a gap that defines and functions as a slit to diffract an acoustic wave.

An elastic wave device includes a piezoelectric substrate, a first elastic wave element on the piezoelectric substrate and including at least one first interdigital transducer electrode and a first reflector in an area of the first interdigital transducer electrode at one side in a propagation direction of elastic waves, and a second elastic wave element on the piezoelectric substrate and including at least one second interdigital transducer electrode and a second reflector in an area of the second interdigital transducer electrode at one side in the propagation direction of elastic waves. The first and second reflectors are disposed side by side in the propagation direction. A reflection member, between the first and second reflectors, reflects elastic waves in at least a direction different from the propagation direction.