Design and characterization of a 6 × 6 planar reconfigurable transmitarray

This paper presents the design and experimental characterization of a planar 6×6 fully reconfigurable transmitarray at 5.7 GHz. First, the design of the array element, which consists of two varactor diode-loaded patches coupled by a varactor diode-loaded slot, is presented. The design is optimized by full-wave simulation, followed by experimental characterization in waveguide. The element exhibits the behavior of a third-order tunable filter and achieves 245 degrees of phase agility with less than 3 dB of variation in transmission magnitude in the tuning range. Next, the design and fabrication of a planar array is described, and the varactor biasing scheme is discussed in detail. Finally, two-dimensional beamforming results are presented. Not only is this transmitarray able to demonstrate full two-dimensional reconfigurability and beamforming as an array lens, it is also low-profile, low-cost, and easy to fabricate, making it very attractive for applications where high-gain beam-scanning is needed.