Fujitsu Media Devices Limited

Fujitsu Corporation

Taiyo Yuden Co., Ltd.

Koichi Wada

Satoshi Orito

Satoshi Ichikawa

Toshifumi Tanaka

Hirotada Wachi

Tsuyoshi Oura

Shogo Inoue

Seiichi Mitobe

Toru Takezaki

Tohru Takezaki

A lattice-type filter circuit includes first and second balanced signal terminals; first and second balanced signal terminals; a first resonator connected to a series arm between the first balanced signal terminal on the input side and the first balanced signal terminal on the output side; a second resonator connected to a series arm between the second balanced signal terminal on the input side and the second balanced signal terminal on the output side; a first resonant circuit including impedance elements, being connected to a lattice arm between the first balanced signal terminal on the output side and the second balanced signal terminal on the input side; and a second resonant circuit including impedance elements, being connected to a lattice arm between the second balanced signal terminal on the output side and the first balanced signal terminal on the input side.

Balanced lattice filter device

A filter device has a novel structure, satisfying requirements to have balanced input and output, with a small number of configuration elements. The above filter device includes first and second balanced signal terminals on the input side to be connected to an external balance circuit; first and second balanced signal, terminals on the output side to be connected to an external balance circuit; at least one first resonator connected in series between the first balanced signal terminal on the input side and the first balanced signal terminal on the output side; at least one second resonator connected in series between the second balanced signal terminal on the input side and the second balanced signal terminal on the output side; and at least one impedance element connected between the first balanced signal terminal on the output side and the second balanced signal terminal on the input side.

Filter device with balanced signal input and output terminals

A surface acoustic wave apparatus has a configuration by which the spurious of the higher-order transverse modes is suppressed and a SAW excitation intensity distribution is not changed in the propagation direction. The surface acoustic wave apparatus has at least one interdigital transducer, which is disposed such that a plurality of comb-shape electrodes respectively connected to common electrodes are interleaved, wherein a region with the plurality of interleaved comb-shape electrodes has a first overlapping region with a overlapping length constant over a whole area along a propagation direction of a surface acoustic wave and a second overlapping region formed on at least one side of the first overlapping region with a overlapping length weighted in the propagation direction of the surface acoustic wave, and wherein an overlapping-length weighting envelope curve in the second overlapping region has at least two changing points in the propagation direction of the surface acoustic wave.

Surface acoustic wave apparatus

A surface acoustic wave apparatus has a configuration by which the spurious of the higher-order transverse modes is suppressed and a SAW excitation intensity distribution is not changed in the propagation direction. The surface acoustic wave apparatus has at least one interdigital transducer; a region with the plurality of interleaved comb-shaped electrodes is formed with two regions which are a first overlapping region and a second overlapping region with overlapping-lengths weighted along a propagation direction of a surface acoustic wave; the first overlapping region and the second overlapping region are in contact or overlapped in a direction vertical to the propagation direction of the surface acoustic wave; and in either the first or the second overlapping region, an overlapping-length weighting envelope curve has at least two or more changing points in the propagation direction of the surface acoustic wave.

A surface acoustic wave device includes a piezoelectric substrate, at least one interdigital transducer (IDT) provided on the piezoelectric substrate, and a shield electrode provided on the piezoelectric substrate. The IDT has a first pattern on an edge that faces the shield electrode. The shield electrode has a second pattern on an edge so as to be evenly spaced apart from the first pattern.

Surface acoustic wave device

A surface acoustic wave (SAW) device includes a piezoelectric substrate, a first and a second interdigital transducers (IDT) provided thereon. The second IDT has a side that is substantially aligned with a corresponding side of the first IDT, and another side of the second IDT is arranged so that the second IDT may adjust a leaked wave caused resulting from by a power-flow angle of the piezoelectric substrate.

A surface acoustic wave device includes a piezoelectric substrate, a first and a second interdigital transducers (IDTs) provided on the piezoelectric substrate. The first IDT includes multiple tracks having different frequency characteristics that are connected in parallel. The second IDT includes a normalized electrode pattern. The frequency characteristic of the multiple tracks is asymmetric to a center frequency of the SAW filter, substantially flat in a passband when those of the multiple tracks are overlapped, or complementary in the passband. Thus, it is possible to provide the surface acoustic wave device having a high damping property.

Surface acoustic device

A filter includes a piezoelectric substrate, and interdigital transducers (IDTs) that are formed on the piezoelectric substrate. At least one of the IDTs has a main electrode finger pattern that is weighted. The IDT having the main electrode finger pattern also has a sub electrode finger pattern that is connected in parallel to the main electrode finger pattern, and generates a surface acoustic wave that cancels a surface acoustic wave caused by leakage electric fields generated in the main electrode finger pattern.

Growing community of inventors

Yokohama, Japan

Koichi Wada