Design and Analysis of a Wideband Low-Scattering Endfire Antenna Using a Moth Tail-Inspired Metamaterial Absorber and a Surface Waveguide

This article presents a wideband endfire antenna codesigned with broadband low-scattering characteristics. The wideband reflection and endfire radiation attribute the success to the supported dual-resonance surface waves, and the broadband low scattering owes to the combination of a metamaterial absorber (MA) absorption and an incident penetration of a frequency-selective surface (FSS). Based on the transmission line model, a surface waveguide (SWG) which can support dual-resonance surface waves is adopted and analyzed to realize the wideband reflection response (4.95-6.83 GHz) and endfire radiation. Also, the SWG can be seen as an FSS for the normal incidence. In addition, a wideband MA, which is inspired by the luna moth's escape from bat attack, is designed and integrated with the SWG to realize low back radar cross section (RCS) in the frequency range from 0.5 to 12.5 GHz. The reflection, radiation, and scattering performance are validated by the full-wave simulation and experimental verification.