| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a small and inexpensive portable radio communication machine which uses two frequency bands at different timings. SOLUTION: In a portable telephone set using a 800 MHz band and a 1,500 MHz band at different timings, the capacitance value of a varicap diode 3 is controlled. Thus, the resonance frequency of an antenna 1 is set to be the 800 MHz when the 800 MHz band is used and to be a 700 MHz band, when using the 1,500 MHz band. Then, the resonance of the 1,500 MHz band is obtained at twice the resonance. Consequently, the portable telephone set using the two frequency bands can be constituted in the same size and cost as a portable telephone set, using the single-frequency band.</p> |
