Design of a wideband miniature dielectric-filled waveguide antenna for collision-avoidance radar

This article presents a theoretical and experimental study of the design of a miniaturized wideband dielectric-filled waveguide (DFW) antenna. The ope rational frequency is X band, i.e., 9.0 less than or equal to f less than o r equal to 10.5 GHz. The desired bandwidth is 1.5 GHz. The antenna uses an air-gap matching network to reduce its high aperture reflection. In order t o ease the integration with antenna circuits and to increase the bandwidth, two E-plane steps are used. The antenna is designed to have -3 dB beamwidt hs of 60 degrees and 100 degrees for the E- and H-plane patterns, respectiv ely. An input reflection of less than -10 dB for the desired bandwidth is o bserved. The gain of the antenna is 7 dBi. A cross-polar level of less than -25 dB is achieved. This article discusses the mathematical model for inpu t reflection, the design scenarios, and the experimental results.