Broadband RCS reduction of microstrip antenna in the THz Band

This paper presents a solution to the broadband monostatic and bistatic Radar Cross Section (RCS) reduction of a micrometer wave antenna operating at 3.8 THz without much deterioration in its radiation characteristics. A Frequency Selective Surface (FSS) is proposed which behaves as a linear polarization converter (PC), thus converting linearly polarized electromagnetic waves to cross-polarized waves over two frequency bands. The PC is constituted of a finite geometrical pattern made of copper etched on the top of a dielectric substrate made of polyimide and copper layer at the bottom. Broadband polarization conversion efficiency reaches over 90% for the range of 3.72–4 THz and 5.52–6.28 THz with resonances occurring at 3.84 THz and 5.92 THz at which 99.5% and 99.8% polarization conversion efficiency are acquired, respectively. A meticulous arrangement of PC cells around a planar microstrip antenna is reported for maximum RCS reduction of co-polarized waves from 1 to 10 THz.