Dual-Band Beam-Scanning Antenna Using Rotatable Planar Phase Gradient Transmit Arrays

A design of dual-band beam-scanning antenna using rotatable planar transmitarrays (TAs) is proposed in this communication. The antenna is composed of a dual-band lens and a pair of linear phase gradient (PG) TAs. The presented anisotropic lens is polarization independent, operating at two frequency bands. The PG TA is implemented by using double square loop units with different PGs at two frequencies. Two rotatable PG TAs are located above and parallel to the dual-band lens, and beam scanning in the upper hemisphere is achieved by rotating the two PG TAs synchronously around the axis orthogonal to the planes of the PG TAs. The procedure is demonstrated for dual-band beam-scanning implementation operating in linear polarization at $X$ - and $Ku$ -band. The full-wave simulation results demonstrate that the designed antenna enables beam steering in both azimuth and elevation planes at 8 and 14 GHz, with a peak gain of 16.7 and 19.8 dB in the broadside direction, respectively. Moreover, a prototype is fabricated, and the measured results confirm the feasibility of using this method for achieving low-cost lightweight, simple configuration dual-band 3-D coverage beam-scanning antenna.