Abstract-A new design for circularly-polarized (CP) slot antennas is first described. The antenna is a combination of a shorted square-ring slot and an L-shaped linear slot, and its CP operation frequency can be easily tuned under the condition that the slot area is unchanged. Based on the CP design, two reconfigurable slot antennas are then developed. One is a frequency reconfigurable antenna, whose CP operation frequency can be switched between two adjacent frequencies. The other is a polarization reconfigurable antenna, whose polarization can be switched between two orthogonal CP senses. The two reconfigurable antennas are realized using PIN diodes. Details of the designs and experimental results are shown.

A design for frequency reconfigurable annular slot antennas with circular polarization (CP) is described.The slot antenna is excited with a shorted microstrip line through coupling, and one varactor diode placed on the slot is used to generate CP radiation. By controlling the dc bias of the varactor, the CP operating frequency of the slot antenna can be switched between two frequencies with a frequency ratio of about 1.6; moreover, the antenna operating at each CP frequency has a return loss of less than 10 dB and the broadside radiation with a peak gain of higher than 3 dB. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1115–1118, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27509