To provide an antenna unit and the like, where even if the frequency to be used by an antenna changes continuously or discontinuously, variations will not occur in the characteristics throughout a wide frequency bandwidth.
A matching circuit 103 has a predetermined impedance and freely adjusts the value of the impedance. A frequency dependence compensation circuit 105 obtains the impedance adjustment data of the matching circuit 103 which has been possessed, in advance, based on the center frequency information of a transmission signal from a transmitter 101, and adjusts the predetermined impedance value of the matching circuit 103, in accordance with the adjustment data obtained. Thus, compensation of the frequency dependence of the relative dielectric constant of a medium surrounding an antenna 104, i.e., of a dielectric substrate constituting the antenna, is carried out. According to this compensation operation input impedance of the antenna 104 is held constant, irrespective of the frequency of the transmission signal.
COPYRIGHT: (C)2008,JPO&INPIT
Yoshiaki Naito
Cui Shu Tetsu