| 摘要 |
There is provided an antenna impedance adjuster including (a) an antenna through which radio signals are received and transmitted, (b) a radio signal receiver which receives radio signals having been received through the antenna, (c) a radio signal transmitter which transmits radio signals through the antenna, (d) an adjuster which matches an impedance between the antenna and the radio signal receiver in radio signal receiving band and an impedance between the antenna and the radio signal transmitter in radio signal transmitting band, (e) a first switch which electrically connects the adjuster to one of the radio signal receiver and the radio signal transmitter, and (f) a controller which controls an operation of the first switch when a radio signal is received or transmitted. The antenna impedance adjuster reduces transmission loss to be generated between an antenna and internal circuits to thereby enhance output-load characteristic in a radio signal transmitting circuit, and prevents degradation of sensitivity in a radio signal receiving circuit.
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