Electronically Reconfigurable Filtering Reflectarray Antenna Using Polarization Conversion Elements with Controllable Conversion Zeros

This communication introduces an electronically reconfigurable filtering reflectarray antenna (RFRA) with good frequency selectivity and wide beam-scanning angle. The proposed reconfigurable element consists of a metal ring loading two PIN diodes at the ring openings, a patch with a complementary split ring, an E-shaped patch, a ground plate, and the DC biasing network for PIN diodes, which can not only convert the y-polarized incident wave into the x-polarized reflected wave, but also offer a 1-bit reflection phase. Furthermore, the proposed element can generate two controllable conversion zeros to permit highselectivity filtering performance and adjustable bandwidth. A RFRA with 40 × 40 elements is analyzed in detail to demonstrate the filtering and beam-scanning capabilities, whose realized gain can reach 26.4 dBi at 29 GHz with an aperture efficiency (AE) of 15.7% and beam scanning angle can reach 60°. For lab-level verification, a 10 × 10 RFRA prototype has been fabricated and measured. The measurement and simulation results align well with each other, demonstrating that the proposed RFRA has good frequency selectivity and wide beam-scanning capabilities.