Conformal Metasurface Radomes for Beamshaping

This paper introduces a design method for creating conformal single-layer passive metasurfaces (MTSs) that tailor the radiation pattern of an enclosed antenna array by lining the inside wall of an arbitrarily shaped radome structure. An example transformation is performed where the radiation pattern of a dipole array, operating in the Canadian 5G New Radio (NR) n78 band (3.3 GHz - 3.8 GHz) with a broadside beam with 108° half-power beam width (HPBW) in the azimuth, is transformed into a 40° HPBW pointed 60° off broadside through the insertion of the proposed MTS. Simulation results for the MTS radome nearly achieve the desired radiation pattern criteria at the design frequency of 3.55 GHz. The addition of the MTS decreases the system efficiency from 88.9% down to 81.9%, while the change in pattern resulted in an increase in the peak realized gain by 2.6 dB at the design frequency of 3.55 GHz. Simulation results are confirmed with an experiment. The MTS radome exhibits a 10 dB feed bandwidth of 9.75% and a 3 dB gain bandwidth of 13.9% in simulation. Measurement results demonstrated better feed and gain bandwidth, exceeding the 14% bandwidth covered by the n78 band.