A wideband high gain conformal self-decoupled multiport antenna for 5G millimeter wave communications

Abstract High gain antenna is a mandate for mm wave communications for combating path loss and fading. In this work, we report a four-port antenna operating over a wide spectrum which covers the FR2 band of 5G, namely n257, n258 and n259 bands respectively using both rigid and flexible substrates having same permittivity but different thickness. A maximum isolation of 53 dB is obtained between the antenna elements. The gain of the multiport antenna is enhanced by integrating it with a wideband polarization insensitive reflective type frequency selective surface (FSS) which exhibits band-stop filtering characteristics from 16.6–35.8 GHz and 17.4–39.3 GHz using rigid and flexible substrates respectively. An equivalent circuit model (ECM) has been proposed for the FSS for investigating its frequency response. In both planar and bent configuration, a maximum gain of 11.5 dBi is obtained over the 81% fractional bandwidth in the frequency band 15–35 GHz. Characteristic mode analysis is conducted for the proposed FSS and antenna for analyzing the current distribution in the dominant resonant modes using finite integration technique. Prototypes of antenna and FSS have been fabricated using both rigid and flexible substrates. The measured results show close resemblance with the simulated results.