Broadband flattened Luneburg lens with ultra-wide angle based on a liquid medium

A two-dimensional flattened Luneburg lens with an ultra-wide viewing angle has been realized based on a liquid medium approach in our present work. A field-of-view angle up to 180 degrees is achieved over the microwave regime. The transformed lens is realized by using a low-loss liquid medium and a large variation of refractive index from 1 to 4.18 is achieved. The non-resonant property of the liquid ensures a broadband and low-loss performance of the lens from 12.4 GHz to 18 GHz. The high directivity and relatively low loss of the proposed lens were demonstrated by simulation and experimental results. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4793206]