Microfluidically Polarization-Switchable Metasurfaced Antenna

This letter reports a polarization-switchable metasurfaced antenna, which comprises a source antenna and a metasurface as a superstrate. The metasurface consists of a 4 × 4 microfluidic element array, and each element is designed with a rectangular loop with diagonals formed by microfluidic injection. The left-hand circular polarization (LHCP), right-hand circular polarization (RHCP), and linear polarization (LP) are achieved by microfluidic injection through different channel inlets on the metasurface. The performance of the proposed antenna in terms of polarization reconfigurability, axial ratio bandwidth (ARBW), impedance bandwidth, broadside gain, and radiation pattern is experimentally verified after fabrication. The experimental results show that the proposed antenna achieves a 3 dB ARBW from 2.47 to 2.55 GHz (i.e., fractional bandwidth of 3.18%) for LHCP and RHCP, with the realized peak gains of 5.86 and 5.84 dBi in boresight for LHCP and RHCP, respectively, at 2.51 GHz. The 10 dB impedance bandwidth of the antenna in LP mode is from 2.32 to 2.52 GHz and from 2.41 to 2.59 GHz in LHCP and RHCP modes, respectively (i.e., fractional bandwidth of 7.2%).