Rectangular metamaterial Luneburg lens for dual polarized multi-beam radiation based on transformation optics

This paper proposes a rectangular metamaterial Luneburg lens antenna with dual polarized multi-beam radiation. Using the transformation optics (TO) principle, the propagation of the electromagnetic wave can be arbitrarily manipulated; therefore, a standard Luneburg lens can be compressed from two dimensions, realizing a miniaturized structure. First, the TO is used to calculate a matrix of dielectric constants that is needed to realize multi-beam radiation. Then, specific metamaterial structures with varying parameters are proposed to realize the targeted dielectric constants. The presented rectangular lens has a size of 3.5 × 1.06 × 0.27λ3, which is sandwiched in the parallel plate waveguide, with three patch antennas to feed the lens. The design is demonstrated with a rectangular metamaterial lens antenna working in the band of 14–15.6 GHz designed to provide dual polarized multi-beam radiation. Experimental results show that the lens antenna can generate multiple beams with a covering range of about 60°, with the realized gain higher than 11 dBi and up to 13.8 dBi. The proposed design provides an effective alternative in scenarios where dual-polarized multi-beam antennas with small footprints are needed, including but not limited to communication based stations and military tracking systems.