Analysis and Characterization of a Multipole Reconfigurable Transmitarray Element

A reconfigurable transmitarray element is presented that operates at 5.5 GHz and is low-profile, low-cost and easy to fabricate. The design consists of a three-layer structure implementing two slot-coupled patch antennas. Varactor diodes are used to load the patches and slot to create a third-order resonant structure. A simple circuit-based analysis approach is used to predict the response of the unit cell based on the location of its poles and zeros. Simulation and experimental results are presented, with experimental results achieving 245° of phase agility with less than 3 dB of variation in transmission magnitude throughout the tuning range. The effects of diode loss, angle of incidence, and mutual coupling are investigated. The element is also capable of functioning as a low-loss reconfigurable reflectarray element, making it particularly versatile for different scanning configurations.