A Compact Pattern Reconfigurable Antenna with 4 Different Radiation Modes

This letter presents the design, fabrication, and measurements of a pattern reconfigurable antenna operating at 3.3 GHz. A circular patch in the center and a ring around it are excited by two feeds to obtain broadside and conical radiation patterns through out of phase and in phase excitations, respectively. In order to improve the pattern diversity ability of the antenna by introducing asymmetry to the radiation patterns, two slots are opened in the ground plane of the microstrip antenna. Short circuiting one of these slots results in an asymmetric pattern in conical beam mode and steers the main radiation direction in broadside radiation mode.