Sidelobe Suppression in Both the E and H Planes Using Slit Layers over a Corporate-Feed Waveguide Slot Array Antenna Consisting of 2×2-Element Radiating Units

Abstract

The sidelobe level at tilts around 30-40 degrees in both the E and H planes due to a tapered excitation of units of 2×2 radiation slots is suppressed by introducing slit layers over a corporate-feed waveguide slot array antenna. The slit layers act as averaging the excitation of the adjacent radiating slots for sidelobe suppression in both planes. A 16×16-element array in the 70 GHz band is fabricated. At the design frequency, the sidelobe levels at tilts around 30-40 degrees are suppressed from −25.4 dB to −31.3 dB in the E-plane and from −27.1 dB to −38.9 dB in the H-plane simultaneously as confirmed by measurements. They are suppressed over the desired range of 71.0-76.0 GHz frequencies, compared to the conventional antenna.