Electronically Reconfigurable FSS-inspired Transmitarray for Two Dimensional Beamsteering

A novel electronically reconfigurable transmitarray with two-dimensional beamsteering capability is presented in this paper. The proposed structure, inspired on frequency selective surfaces loaded with varactor diodes, allows to the phase range of each transmitarray element to be individually controlled enabling an automated steering of the main lobe of an original antenna pattern, in both elevation and azimuth planes (2D-beamsteering). This has been demonstrated on a 5 × 5 unit-cell stacked structure with active feeding, coupled to the aperture of a standard gain horn antenna. A complete electromagnetic study using CST Microwave Studio is presented to evaluate and characterize the transmitarray elements and the effect the proposed feeding network has on the structure’s behavior. Following initial simulations, a prototype of the active transmitarray have been characterized. Automated antenna beamsteering with ranges up to Az = 28° and El = 26° and 1° of angular resolution, is achieved by means of electromagnetic simulations and validated against experimental results at 5.2 GHz.