Metasurface-Inspired Low Profile Polarization Reconfigurable Antenna With Simple DC Controlling Circuit

A wide-band metasurface inspired polarization reconfigurable antenna with a low profile and a simple DC controlling circuit is introduced and analyzed in this paper. The proposed antenna consists of three parts, i.e., a coplanar waveguide-fed slot coupling antenna with slot slanted angle of 40 degrees, a metasurface superstrate which is composed of a $3\cdot 4$ array of metallic rectangular patches, and a simple DC bias controlling circuit including p-i-n diode switches, metallic vias, chip inductors, and bias lines. When all the p-i-n diode switches are in ON state, the antenna will work in linear polarization state and generates linear polarized (LP) wave, the measured operating band ranges from 5.2 to 6.2 GHz (17.5% −10 dB impedance bandwidth), while the measured average realized gain is 6.2 dBi. When all the PIN diode switches are in OFF state, the polarization state of the antenna will alter to left-handed circular polarization and produces left-handed circular polarized wave, the measured −10 dB impedance bandwidth and 3 dB axial ratio bandwidth are 20.7% (ranges from 5.2 to 6.4 GHz) and 15.1% (ranges from 5.5 to 6.4 GHz), respectively, while the average realized gain is 7.1 dBi. Measured results of the reflection coefficients, realized gains at broadside, axial ratio, and radiation patterns are in good agreement with numerical simulations, which verifies the effectiveness and correctness of the proposed design.