Communication circuit, communication apparatus, impedance matching circuit and impedance matching circuit designing method

摘要

A communication circuit is provided with an antenna section, such as a nonresonant antenna, and a matching section which connects with the antenna section and adjusts impedance, for example. The matching section has a transmission line, and the electric length and characteristic impedance of the transmission line are determined based on the frequency or the frequency band in which the antenna section and the transmission line resonate. For example, since it is not necessary to unite resonance frequency with center frequency if it is a nonresonant antenna, it becomes possible to attain the miniaturization of an antenna. Wide band-ization is realizable by changing the characteristic impedance of the transmission line.