Ultra-Wideband Geodesic Lens Antenna for Point-to-Point Communications

Here, we present the design of an ultra-wideband geodesic generalized Luneburg lens antenna, operating in the 10-40 GHz frequency band. This is the widest band ever reported in the literature for a geodesic lens antenna. The most innovative aspects of the design are (i) the feed, which is based on coaxial-to-ridge transition, and (ii) the broadband implementation of a compact array of flares which increases the directivity in the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$E$</tex>-plane. The challenges in the design are related to the matching of the feeding to the lens, as well as keeping a good matching of the array of flares without excessively increasing the longitudinal size of the antenna and avoiding grating lobes in the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$E$</tex>-plane. The antenna features a maximum directivity of 25 dB. Given the fully metallic nature of the antenna, we expect a high radiation efficiency in the measurements.