Pattern reconfigurable slot antenna with broadband operation

A pattern reconfigurable design using a single-feed slot antenna is presented. Several PIN diodes are embedded into the ground plane, and by controlling the states of the diodes, the antenna structure can be worked as a 0.5 λ slot antenna and a 0.75 λ monopole slot antenna. A prototype is designed to give three different radiation modes in the H-plane, and these modes can respectively generate an omnidirectional pattern and two unidirectional patterns with reversed main-beam directions. Experimental results indicate that the omnidirectional mode has a gain variation of about 6 dB across all azimuthal angles and the unidirectional mode has a front-to-back ratio of higher than 10 dB. In addition, the working bandwidth of the reconfigurable antenna is more than 15 %.