| 摘要 |
PROBLEM TO BE SOLVED: To provide a very effective technology for a GSM (global system for mobile communications) radio terminal which realizes multiband compatibility with a small circuit configuration and high performance, and whose future demand will further increase. SOLUTION: This multiband switching antenna duplexer is applied to a mobile telephone used for a TDMA (time division multiple access) system such as a GSM, and a single antenna is shared by signals of four different frequency bands (GSM850, EGSM (extended GSM), DCS (digital communication system), and PCS (personal communication service)). By combining receiving filters 24, 27, 44, and 47 with switching devices of diodes 9, 10, 11, and 12; the antenna duplexer can switch bands with very high performance by the minimum number of switching devices. By this antennal duplexer's circuit, not only a multiband switching antenna duplexer is miniaturized, but also a radio terminal itself is improved in performance and miniaturized. COPYRIGHT: (C)2005,JPO&NCIPI
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