Matsushita Electric Industrial Co., Ltd.

Kazushi Nishida

Yuki Satoh

Mitsuhiro Furukawa

Toru Sakuragawa

Ichiro Kameyama

Hiroshi Fujinaka

Kiyoharu Yamashita

Katsuya Fujii

Hiroshi Kurotake

The disclosed is a downsized and power saving antenna duplexer. The antenna duplexer includes: diplexer; first surface acoustic wave filter to transmit/receive low channel frequency band signals; first phase shift circuit to match the transmission phase with the reception phase of first surface acoustic wave filter; second surface acoustic wave filter to transmit/receive high channel frequency band signals; second phase shift circuit to match the transmission phase with the reception phase of second surface acoustic wave filter. Diplexer, first phase shift circuit and second phase shift circuit are formed in a monolithic structure in package that includes surface acoustic wave filters. The configuration can provide the antenna duplexer with a compact size, a lower current consumption and a highly efficient performance.

Antenna duplexer

In a surface acoustic wave device, a common portion and a strip portion of a reflector electrode are partially cut off to increase a space between the electrodes. The increase of the space between the electrodes reduces the influence of the amount of charges and the influence of an unbalance between the amounts of charges in etching of a metallic film, thereby preventing the electrodes from having a curved shape in section. Consequently, the surface acoustic wave device has a reduced propagation loss.

Surface acoustic wave device and electronic component comprising it

An antenna duplexer capable of optimally decreasing the insertion loss and the voltage standing wave ratio (VSWR) at a center frequency and its vicinity in the pass band in transmitter-band of the device. The output port of transmitter surface-acoustic-wave (SAW) filter ( ) is electrically connected with phase shift circuit ( ), to which receiver SAW filter ( ) is also electrically connected. The transmitter and receiver SAW filters have different pass bands and attenuate the other pass band with each other. Phase shift circuit ( ) shifts the phase of receiver SAW filter ( ) in the transmitter-band. In addition, phase shift circuit ( ) has the characteristic impedance in which the magnitude of the reflection coefficient at the center frequency in the transmitter-band of receiver SAW filter ( ) is to be not less than 0.8 and the phase angle of reflection coefficient at the center frequency in the transmitter-band of receiver SAW filter ( ) takes the range from 0&deg; to 45&deg;.

SAW antenna duplexer having a phase shifter with less than 50 ohm characteristic impedance

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Osaka, Japan

Kazushi Nishida