Half-Annular Leaky-Wave Antenna With Suppressed Open Stopband: Design and Experimental Testing

A new half-annular bull-eye leaky-wave antenna (LWA) design with suppressed open stopband (OSB) and integrated feeding is presented. The 2-D aperture offers a pencil beam with scanning through broadside and with stable gain values as a function of frequency. To achieve directional radiation, a TM $_{0}$ surface wave supported by a grounded dielectric slab is properly perturbed by means of a suitable planar-periodic double-strip aperture. In addition, the proposed structure offers improved performance and reduced design complexity with respect to previous LWAs having a nonsuppressed OSB. Dispersion analyses based on a well-established method-of-moments approach are also performed to characterize the fast spatial harmonic supported by the structure and to determine the size, position, and periodicity of the strips needed for optimal OSB suppression. Simulations and experiments have been carried out to validate the antenna performance against the optimized unit cell. The fabricated planar-periodic LWA also provides continuous beam scanning from $-35^{\circ }$ to $40^{\circ }$ , with a peak realized gain of 21 dBi.