A Compact Reconfigurable Microstrip Antenna with Multidirectional Beam and Multipolarization

In this communication, a novel pattern and polarization reconfigurable microstrip antenna with a simple structure is presented. By switching four p-i-n diodes integrated with the antenna, the current distribution on the antenna can be altered, thereby changing the antenna performance. The proposed antenna can realize eight operating states of the radiation patterns including one boresight linear polarized (LP) pattern with narrow beamwidth, one boresight LP pattern with wide beamwidth, four directional LP patterns in the xoz plane and yoz plane, and one left-hand circularly polarized and one right-hand circularly polarized pattern with wide beamwidth. The operating frequency band of the antenna is from 3.1 to 3.45 GHz. An antenna prototype has been fabricated to validate the design concept. Good agreement between the simulated and measured results is found, and the cross polarization level is below -21 dB.