Design of Wideband Leaky-Wave Antenna Using Sinusoidally Modulated Impedance Surface Based on the Holography Theory

In this letter, sinusoidally modulated impedance surfaces composed of hexagonal unit cells are used for the implementation of the leaky-wave antennas with frequency scanability in the band of 13-18 GHz. The antenna bandwidth has been studied from two view points-first, from the aspect of the impedance-matching bandwidth and second, from the aspect of the bandwidth scanning of the antenna. In order to improve the performance of the impedance bandwidth, an SIW launcher with a wideband transition is used. In order to improve the frequency-scan capability, a one-dimensional hologram is used. Also the launcher is located at a corner to cancel the destructive effect of the backward radiation. The impedance surface is designed to produce a beam tilt at the angle of 60° at 18 GHz, namely the upper limit of the frequency band. The achieved characteristics of the proposed antenna are 32% bandwidth and angular scan of 22°-60°. A prototype model of the antenna is fabricated and tested as the proof of the concept.