Patent ID: 7269440

Claim:
A cellular phone covering a plurality of frequency bands, comprising: (a) an antenna; (b) a high-frequency circuit; (c) an antenna-matching circuit electrically connecting in series between said antenna and said high-frequency circuit; (d) a first unit which varies a ground length connection to a ground area in accordance with a frequency band in which said cellular phone makes communication with others, wherein said ground area is a ground area of said antenna-matching circuit; wherein said first unit comprises: (d1) a detector which detects a frequency band in which said cellular phone makes communication with others, and transmits a detection signal indicative of the thus detected frequency band; and (d2) a second unit which receives said detection signal, and varies said ground length connection to the around area in accordance with a frequency band indicated in the detection signal; and first to N-th printed substrates wherein N is a positive integer equal to or greater than two, wherein said second unit is comprised of first to N-th switches formed on said first to N-th printed substrates, respectively, said first to N-th switches operate in synchronization with one another, said first to N-th switches are grounded when said detection signal indicates a first frequency band, and make an impedance circuit when said detection signal indicates a second frequency band greater than said first frequency band.