Three-Element Pattern Reconfiguration Antenna Using Partial Ground Plane

In this paper, a three-element antenna with pattern reconfiguration is presented. The three elements include a square driven element at the centre of two parasitic elements. The approach of Yagi-Uda is employed to achieve pattern reconfiguration. The lengths of the parasitic elements are varied using PIN diodes to make one of them act as a director while the other as a reflector and vice-versa. Pattern reconfiguration is achieved by making the length of the parasitic element acting as a reflector larger than the size of the partial ground plane. The proposed antenna, employing two PIN diodes, is designed to radiate the main beam at -90, 0 and 90 degrees. The measured directivity obtained at various scanning angles is about 6.5 dB. The proposed antenna is suitable for WLAN applications operating around 2.4 GHz.