Murata Manufacturing Co., Ltd.

Yohei Konaka

Katsuya Daimon

Morio Takeuchi

Koichiro Kawasaki

An acoustic wave element includes a piezoelectric substrate, an IDT electrode on the piezoelectric substrate, and a reflector. The IDT electrode includes plural electrode fingers, and the reflector includes plural reflector electrode fingers. In a case where IRGAP is an IDT-reflector gap that is a distance between a center of the electrode finger located closest to the reflector and a center of the reflector electrode finger located closest to the IDT electrode, and λis a reflector wave length that is twice a repetition pitch of the reflector electrode fingers, a ratio of about 0.25≤IRGAP/λ≤about 0.44 is satisfied, and the reflector wave length is longer than an IDT wave length that is a repetition pitch of the electrode fingers.

Acoustic wave element, acoustic wave filter device, and multiplexer

An acoustic wave element includes an electrode-finger pitch of reflecting-electrode fingers greater than an electrode-finger pitch pi of comb-shaped electrode fingers, and a center-to-center distance between a reflecting-electrode finger and a comb-shaped electrode finger is equal to or less than about 0.9 times the electrode-finger pitch of the reflecting-electrode fingers. When a reflecting-electrode finger counted from a closest reflecting-electrode finger is designated as a k-th reflecting-electrode finger in order, a reflecting-electrode finger farthest from the IDT electrode is defined as an (n+1)-th reflecting-electrode finger, and an electrode-finger pitch between the k-th reflecting-electrode finger and a (k+1)-th reflecting-electrode finger is defined as a k-th electrode-finger pitch p, a value of electrode-finger pitches from a first electrode-finger pitch pto the k-th electrode-finger pitch pis less than a value of electrode-finger pitches from a (k+1)-th electrode-finger pitch pto an n-th electrode-finger pitch p.

An acoustic wave filter device includes a first longitudinally coupled acoustic wave resonator including an odd number of first IDT electrodes arranged along an acoustic wave propagation direction and a second longitudinally coupled acoustic wave resonator including an odd number of second IDT electrodes arranged in the acoustic wave propagation direction. Among the first IDT electrodes, the odd-numbered IDT electrodes are connected to a node and the even-numbered IDT electrodes are connected to a node. Among the second IDT electrodes, the odd-numbered IDT electrodes are connected to the node and the even-numbered IDT electrodes are connected to the node. The number of first IDT electrodes connected to the node and the number of second IDT electrodes connected to the node are the same.

Acoustic wave filter device and multiplexer

A filter device includes a first ladder filter including serial resonators disposed in a terminal-to-terminal path and parallel resonators disposed in connection paths, a first acoustic wave resonator disposed in parallel to the parallel resonator, and a second acoustic wave resonator disposed in parallel to the serial resonator. Resonance points and anti-resonance points of the first and second acoustic wave resonators are both positioned on the lower frequency side or the higher frequency side of a pass band of the first ladder filter, and on the same side of the pass band of the first ladder filter, when viewed from the pass band of the first filter.

Filter device and multiplexer

An elastic wave apparatus includes a piezoelectric substrate, a first dielectric film provided on the piezoelectric substrate, an IDT electrode provided on the first dielectric film, and a capacitor that includes a pair of comb-shaped electrodes provided directly on the piezoelectric substrate and is electrically connected to the IDT electrode. An elastic wave resonator including the IDT electrode is provided.

Elastic wave apparatus and duplexer

A filter device includes an antenna terminal to be connected to an antenna, first inductors connected between the antenna terminal and a ground potential and defined by parallel divided inductors, and first and second acoustic wave filters commonly connected to the antenna terminal and including second inductors, respectively. The first inductors and the second inductors are electromagnetically coupled to each other mainly in a one-to-one relationship.

Filter device

An elastic wave device includes first and second longitudinally coupled resonator elastic wave elements aligned on a piezoelectric substrate. A second reflector of the first longitudinally coupled resonator elastic wave element and a third reflector of the second longitudinally coupled resonator elastic wave element are adjacent to each other in an elastic wave propagation direction. A ground interconnection extends in a direction intersecting with the elastic wave propagation direction and in a region between the second reflector and the third reflector. A gap in one portion of the ground interconnection includes a different acoustic velocity portion where an acoustic velocity is different from an acoustic velocity in another portion of the ground interconnection.

Elastic wave device, duplexer, and multiplexer

In a high frequency module, in addition to a main transmission path in which a high-frequency signal propagates in first filter elements, a sub transmission path is defined by inductive coupling or capacitive coupling between a first inductor and a matching element or by inductive coupling between the first inductor and a second inductor. The sub transmission path has different amplitude characteristics and phase characteristics from those of the main transmission path depending on a degree of the inductive coupling or capacitive coupling, and transmission characteristics as a high-frequency module are adjustable by adjusting the amplitude characteristics and the phase characteristics of the sub transmission path.

Growing community of inventors

Nagaokakyo, Japan

Yohei Konaka