Phase Gradient Metasurface Rasorber for Combined Beam Steering and Absorption Capability

A novel radome design is presented which acts as a phase gradient metasurface (PGMS) and a radar absorber to provide both beam steering and absorbing functionality. By replacing the traditional frequency selective surface or lossless layer, in a radar absorber (i.e. a rasorber) with a PGMS, a new multi-layer structure is proposed which provides dual functionality. The design consists of a PGMS composed of several differently sized circular plate unit cells with two resistive layers placed a quarter wavelength above it. By this configuration, the radome structure supports steering whilst providing absorption bands from about 1.2 GHz to 5.5 GHz and 6.1 GHz to beyond 10 GHz. To best knowledge of the authors, this design is the first of its kind and it has many interesting applications for future phased arrays and related radar scenarios whilst reducing requirements for antenna beamformers and array phase shifting networks.