Polarization reconfigurable annular ring slot antenna design

Abstract

This paper proposes a simple polarization reconfigurable annular ring slot antenna (ARSA). The proposed ARSA is able to switch among three polarizations, i.e. left-handed circular polarization (LHCP), right-handed circular polarization (RHCP), and linear polarization (LP). The circular polarization (CP) property can be attained by introducing an appropriate inductance at a particular angle across the annular slot. In the design, two PIN diodes are incorporated to provide the required inductance, and at the same time the antenna polarization can be switched by controlling the state of the diodes. The simple design employs the parasitic inductance of the active elements, and hence eliminates the necessity of additional CP perturbation structures. The measured results show that all three polarizations exhibit good impedance matching. Excellent CP performance has been obtained for both circular polarizations with a 3-dB axial ratio (AR) bandwidth (BW) of roughly 6.0%.