L-shaped vertical strip line primary radiator fed by MIC mount for millimeter-wave planar antennas

A primary radiator for 2-dimensional offset parabolic reflectors was investigated for millimeter-wave planar antennas, which was constructed by a slit array fed by an oversized waveguide. The primary radiator consists of the vertical strip transmission line on which an L-shaped radiating element was etched. At first, a reflection plate was installed behind the L-shaped radiating element, and the spacing between the L-shaped radiation element and the reflection plate was decided by calculating radiation patterns. It was obvious that a broad radiation pattern was obtained, and a backward emission was suppressed by selecting the spacing. And moreover, the radiation pattern versus the width of the reflection plate was calculated from the viewpoint of the size reduction. Based on the calculated radiation patterns and related characteristics, it was confirmed that this radiator would be suitable interface between the planar antenna and MICs at millimeter wavelengths.