Improvement of isolation between transmitting and receiving antennas of E-plane arranged waveguide slot arrays by using layers of slit pairs with half-wavelength spacing

Abstract

In this paper, we propose loading layers of slit pairs with half-wavelength spacing over a corporate-feed waveguide slot array antenna in the 30 GHz band. This structure is expected to improve the isolation between transmitting and receiving antennas arranged in the E-plane. As a result of the design, the reflection of the radiating element is suppressed under -14 dB over a target band (27.8 GHz - 31.4 GHz). The isolation between two antennas using a 2×32-element model is improved by about 20 dB compared to the conventional structure without the slit-pair layers. We demonstrate this result by measurement using 64×32-element arrays.