Dual-band reconfigurable metasurface-assisted Fabry-Perot antenna with high-gain radiation and low scattering

The authors have proposed a dual-band reconfigurable Fabry-Perot (F-P) cavity antenna with high gain and meanwhile small radar cross-sections (RCSs) in wideband. Different from the traditional F-P antennas, they used a dynamic metasurface reflective plane (DMRP) as the lower superstrate to realise reconfigurable functions and a digital coding metasurface as the upper superstrate to achieve wideband RCS reduction. To investigate the dual-band reconfigurability, a wideband rectangular waveguide is used to feed the F-P antenna. By varying the bias voltage applied to varactors embedded in the elements of DMRP, the reflection phase of DMRP is changed and the two operating frequencies can be tuned electronically. To realise RCS reduction, they adopted a meticulous arrangement of the coding elements on partially reflecting surface. The designed metasurface-assisted F-P antenna has good radiation performance with high gain, high aperture efficiency, and high radiation efficiency. In the experiments, a prototype was fabricated via printed circuit board technology, and measured results agree well with numerical simulations. The measured peak gain reaches 17.52 dBi and the maximum aperture efficiency is 56.97%. The two reconfigurable bandwidths cover 5.10-5.40 and 6.60-6.93 GHz, respectively; and 7 dB RCS reduction is achieved from 9.40 to 13.7 GHz for arbitrary polarisation