Wideband Low Profile Multi-Polarization Reconfigurable Antenna with Quasi-cross-shaped Coupling Slot

A wideband low profile multi-polarization reconfigurable antenna with quasi-cross-shaped coupling slot is proposed. The antenna consists of an upper oval radiating patch, the quasi-cross-shaped coupling slot, fork-shaped folded feed lines and a reconfigurable Wilkinson power divider network with four pairs of p-i-n diodes. The antenna reconfigurable polarization modes change among +/- 45 degrees Linear polarization (LP), dual-LP, left-hand circular polarization (LHCP) and right-hand circular polarization (RHCP) by controlling the ON/OFF states of the p-i-n diodes. The designed prototype has been fabricated and measured. Good agreement between the measured and simulated results is achieved. Measured results show that the antenna has wide impedance bandwidth (over 21.35% for LP and 17.70% for CP) and axial ratio (AR) bandwidth (16.13% for LHCP and 16.88% for RHCP). The average realized gains are about 7.6 dBi for different polarization modes. The proposed antenna has the advantages of multi-polarization reconfigurable ability, wide bandwidth, low profile, and high gains, which make it possible to be applied to wireless communication systems.