Matsushita Electric Industrial Co., Ltd.

Riho Sasaki

Yuki Satoh

Tatsuya Inoue

Hiroshi Kushitani

Yoshiharu Omori

Hideaki Tokunaga

Keiichi Noi

Narihiro Mita

Kaori Shiraishi

Kotaro Suzuki

A high-frequency hybrid switch module arranged applicable to at least two different communications systems includes two low pass filters (LPFs), two phase shifters, a field effect transistor (FET) switch including FETs, and two SAW filters. The FETs and the SAW filters are mounted on a layered assembly including the LPFs and an electrode pattern of the phase shifters. The module can have a small overall size, a low cost, and a small loss, while being protected from static electricity. The module requires small number of low-noise amplifiers at a signal receiving side.

High-frequency composite switch module

The invention aims to provide a high-frequency device enable to protect circuits connected to an antenna terminal from possible intruding static electricity or high voltage noises. Diplexerconnected to antenna terminalcarries out demultiplexing or multiplexing frequency for GSM or DCS band. Circuits to process frequency for GSM and DCS band have switchesandrespectively for switching to transmit or to receive signals for diplexer. Switchandare connected to low pass filtersandrespectively to clear off higher harmonics in transmitting signals, and are connected to SAW filtersandhaving respective specific pass bands. Filtersandare connected to terminalsandrespectively. Moreover, a first end of varistoris connected between antenna terminaland diplexerand a second end of varistoris connected to ground terminal.

High-frequency device

A precipitate film having plating resistance may be formed on the surface of a varistor element during sintering process. Accordingly, the manufacturing process can be shortened, thereby improving the productivity. The manufacturing method comprises (a) a first process of forming the varistor element whose main component is zinc oxide; (b) a second process of sintering the varistor element and precipitating zinc compound having at least one of acid resistance and alkali resistance on the surface of the varistor. Preferably, the manufacturing method further comprises (c) a process of attaching an external electrode to the varistor element, and the external electrode attaching process is executed after finishing the varistor element sintering process.

Zinc oxide varistor and method of manufacturing same

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Osaka, Japan

Riho Sasaki