Matsushita Electric Industrial Co., Ltd.

Nobuo Fuse

Kaoru Ishida

Hiroaki Kosugi

Hiroshi Haruki

Hideki Yagita

Hikaru Ikeda

Makoto Sakakura

Hisanaga Miyoshi

Kouji Hashimoto

A surface acoustic wave device has a structure in which a surface acoustic wave element (), provided with two kinds of surface acoustic wave filter structures having different center frequencies on the same piezoelectric substrate (), is disposed on a package (). The surface acoustic wave element () comprises a first filter structure () having a first center frequency, a second filter structure () having a second center frequency and a shield electrode () between the first filter structure () and the second filter structure (). The shield electrode () is connected to an earth terminal () of the package () to be grounded. According to the structure, electromagnetic shielding between the first filter structure () and the second filter structure () can be performed, therefore, the isolation property therebetween can be improved and the surface acoustic wave device can be miniaturized.

Surface acoustic wave device

The output of a digital modulator is put into a power amplifying device, is distributed into n pieces in an n-power divider in the power amplifier, passes through n input phase shifters differing individually in the phase change amount, is amplified by n power amplifiers, passes through n output phase shifters to match the phase of n signals, is combined in an n-power combiner, and is issued from an output terminal to a phase shifter, and the output of the phase shifter is issued to a transmission antenna. Herein, the phase value of the phase shifter is determined so as to extend the region of the output load impedance for satisfying the specific value of unwanted radiation, and so that the output load impedance range of the load impedance of the power amplifier may be optimize to the impedance change range of the trans missionantenna, thereby eliminating the isolator and presenting a transmitting device of a portable wireless system realizing smaller size, higher performance, and lower cost of portable wireless system.

Transmitter of wireless system and high frequency power amplifier used

A dual band oscillator circuit according to the present invention comprises an oscillator circuit portion that oscillates at a first frequency, an oscillator circuit portion that oscillates at a second frequency, a buffer amplifier circuit portion to which an output of the first oscillator circuit portion is input through a first stage-to-stage coupling element and an output of the second oscillator circuit portion is input through a second stage-to-stage coupling element. Operation is switched between the first and second oscillator circuits by an externally applied control voltage signal.

Dual band oscillator circuit using strip line resonators

Growing community of inventors

Osaka, Japan

Nobuo Fuse