An antenna system is ordinarily designed independently from transmitter or receiver circuitry, to which the antenna is connected by a transmission line. Unlike such an ordinary antenna system, an integrated antenna system (IAS) incorporates components, either passive, active, or both, into the antenna structure. The term integration here implies unification of an antenna and device or circuitry so that the performance of the antenna system is determined by both the antenna and the integrated device or circuitry. By means of integration, one can expect either improvement or modification of the antenna characteristics, or enhancement of antenna performance due to the addition of functions introduced by the integration.