High-gain and low-profile dielectric-image-line leaky-wave-antenna for wide-angle beam scanning at sub-THz frequencies

A low-profile THz leaky-wave antenna (LWA) enabled by a Dielectric Image-Line (DIL) with wide beam steering capability is reported for the first time in this paper. The DIL as a low-loss dielectric waveguide synthesized directly on a substrate with high dielectric permittivity is an appropriate candidate for emerging directive compact antennas for future sub-THz wave communications. The dominant mode of DIL is disturbed by printing two periodic set of radiating elements on the top wall of DIL, including three barrier strips and two anti-reflection strips with an extensive tuning range for open stop-band (OSB) suppression. The operation bandwidth of the proposed antenna spans from 142 GHz to 225 GHz providing an impedance bandwidth of 48.8% in the fast wave region. It is observed from numerical simulations that the proposed 35-cell leaky wave antenna permits a beam steering angle of 128° (−68° to 60° (including the broadside)) in the operation frequency band with the gain varying from 14 to 19.3 dBi in the fast wave region. Detailed design guidelines along with simulation results are presented. The proposed antenna has the capability of being directly scaled to other frequency bands by considering its corresponding dispersion characteristic.