Design of a Wideband Reflectarray Antenna on FR4 Substrate for Dual Linear Polarization at 100 GHz

This paper presents the design of a wideband reflectarray antenna supporting dual polarization in simulation. The unit cell comprises two orthogonal sets of three coplanar parallel dipoles printed on two surfaces. The lengths of the coupled dipoles are optimized and varied to achieve a phase range exceeding 360 degrees for both orthogonal linear polarizations. Simulation results show peak gains of 32.9 dBi for x-polarization and 30.84 dBi for y-polarization at 100 GHz. The antenna also exhibits a 3 dB gain bandwidth of 17% for x-polarization (93 GHz to 110 GHz) and 25% for y-polarization (93 GHz to 118 GHz), with low cross-polarization levels.