Broadband planar Luneburg lens composed of artificial impedance surfaces

A two-dimensional Luneburg lens is presented based on artificial impendence surfaces (AIS). The desired refractive index profile is controlled by the variable surface impendence, which obtained by using an array of complementary unipolar compact photonic band gap (UC-PBG) structure inside a parallel plate waveguide. Simulation results have shown that proposed Luneburg lens, which operating in TM mode during X-band, has an excellent focusing ability. The proposed Luneburg lens can be used in direction of arrival (DOA) estimation. The estimation error is smaller than 5°.