RADIO TRANSMITTER/RADIO RECEIVER UNIT COMPRISING A TUNEABLE ANTENNA

摘要

The invention relates to a radio transmitter/radio receiver unit which is capable of transmitting and receiving in different frequency ranges with a stable antenna gain that remains practically constant. According to the invention, a dielectric body, whose dielectricity can be modified is placed in the vicinity of an antenna body. A control unit supplies a d.c. voltage to the antenna which causes the dielectricity of the dielectric body to be modified. The control unit modifies the d.c. voltage value until the dielectricity guarantees an optimum value for at least one physical input variable, which represents the reception and transmission quality.