High-Power-Capable, Ultra-Wideband, 1-Bit, Reflectarray Unit Cells Using Polarization-Rotation Reflection Modes

Abstract

Two ultra-wideband, reconfigurable reflective polarization-rotating (PR) elements are presented in this paper for high-power microwave applications. While one structure provides wider bandwidth, the other one is less challenging to fabricate and is likely more robust mechanically. The proposed structures use two dipole antennas connected to a switching circuit integrated with four, commercially-available, PIN diodes at the backside of a ground plane. Switching between different on-off combination states of the PIN diodes provides 0° or 180°phase shifts yielding a tunable, 1-bit, phase-shifting unit cell. Full-wave electromagnetic simulations predict that both PR unit cells should provide a high co-polarization reflection coefficient (Ryx> −1 dB) and 180° phase difference over an ultra-wide bandwidth. Thermal simulations predict that the PR unit cells should tolerate a continuous-wave illumination power density level of at least 22 W/cm2, while keeping the PIN diode switch junction temperatures below 85% of their maximum rated values.