A radiation pattern-reconfigurable antenna for wireless communications

In this paper, a radiation pattern-reconfigurable antenna is designed to operate over DCS 1800 and PCS 1900 frequency bands. The electrical shape of the proposed antenna is symmetric about the vertical center axis. Depending on the switching state, the antenna alternates its beam direction between the two patterns with no input impedance variation. The antenna size is optimized in order to use PIN diodes and FET switches as the antenna switching elements. The equivalent linear circuit models of both elements are then illustrated, corresponding to on and off states. The simulated results show that the antenna can apparently change its directivity by controlling the switching state.