A novel method to reduce physical dimensions of reflectarray antennas using near-field feeding

This work proposes a novel way to reduce overall volume of reflectarray antennas while maintaining aperture efficiency relatively high. Different from conventional approaches, a feeder antenna is placed very close to the proposed reflectarray ground plane. In order to prevent expected degradation in antenna performance, which is mainly because the feeder is very close to the reflectarray, we impose an additional condition maximizing constructive interference between direct and reflected waves. Consequently, we can show that our antenna can provide relative high antenna gain and aperture efficiency even the antenna is remarkably reduced. Excellent agreement between simulation and experiment proves the validity of our proposal.