Design guidelines for single and dual wide band leaky periodic microstrip line antennas

Abstract

Leaky wave antennas using periodic microstrip lines are natural choices for versatile beam scanning applications. In this work, a shorted stub and an open stub are simultaneously used in the same unit cell to generate resonant frequencies dependent on the stub dimensions. Placing one such resonant frequency at the second Bragg stop band, a single wideband response is obtained. Next, the stub lengths are tuned to obtain two resonant frequencies which are placed at the second and fourth Bragg stop bands, respectively to obtain a dual wideband response. Design guidelines are outlined for obtaining these wide bands and corresponding radiation regions. Two such geometries with single and dual-band nature are fabricated. The single wide-band antenna has a pass-band from 5.89 to 11.57 GHz with a beam scanning range of −56° to 33°. The dual-band antenna has two pass-bands radiating in the frequency range 5-6.5 GHz and 10.7-14.7 GHz. Beam scanning range in the first pass-band is −72° to −5°. The second pass-band, in part, demonstrates a dual-beam nature with the forward beam scanning from 28.9° to 54.5° and backward beam scanning from −54.5° to 14.76° as the frequency varies from 12 to 14.5 GHz.