Compact dipole antenna with multiple radiation pattern reconfigurations

An antenna with four sets of PIN diodes-loaded parasitic strips and reflectors is designed to realize multiple reconfigurable radiation pattern. Parasitic strips are placed between the dipole and reflectors to change impedance of the dipole, thus reducing the distance between the dipole and the reflector. The size of the whole antenna is only 0.1λ₀×0.1λ₀. Moreover, by switching and controlling the PIN diode, the parasitic strip and reflector can perform as a director or a reflector, a Yagi-Uda antenna. As a result, the antenna can provide three modes with nine fundamental radiation patterns. Two modes can realize an eight-beam scanning in the azimuth plane with a 45°-angle-interval at the frequency of 1.575GHz. The peak gain more than 7dBi of all the beams are achieved at the elevation angle of 60°. Another mode can generate an approximate conical radiation pattern. The maximum gain is 5.1 dBi, achieved at the elevation angle of 50°.