W-band short distance CW-radar antenna optimized by housing design

A highly integrated W-Band Vivaldi antenna for radar systems in LTCC is presented. The antenna properties are optimized for high accuracy CW radar short distance measurements by the housing design. The presented technique allows to reduce the phase error resulting by multipath reflections and a non-linear phase front in the near field by decreasing the beamwidth using a tapered horn around the planar Vivaldi antenna. The paper describes the phase error sources and the influence of the metallic horn around the antenna. The electrical field propagation is explained and the limitations of the optimization because of higher propagating modes in the housing are determined. All results are verified by measurements.