Customized compact dielectric lens to improve double-ridge horn antenna performance for automotive immunity EMC test

In this paper we present a novel dielectric lens design placed in front of a double ridge horn (DRH) antenna to meet the technical requirements for Automotive Electromagnetic Compatibility (EMC) Immunity tests. ETS-Lindgren 3119 DRH is selected as the reference antenna for its superior wide frequency range. In the new lens design, the shape of the conventional Plano-convex lens is modified to accommodate two seemingly contradictory requirements — to increase the gain of the antenna system to meet a target average field strength (100 V/m @ 2m distance), and in the meantime, to maintain the antenna beamwidth for field uniformity (FU) to be better than 6dB over 80% of the total number of frequency points. Additionally, it is desirable to keep the lens size small to reduce the cost and weight. Both numerical simulation and measurements results are shown, indicating that the proposed lens with DRH antenna is well suited for ISO 11451-2 Automotive Immunity tests.