Perturbation analysis of planar periodic leaky-wave antennas fed by cylindrical surface-waves

An accurate but simple perturbation analysis of planar cylindrical leaky-wave antennas (LWAs) is presented. Initially a printed LWA, realized by a grounded dielectric slab (GDS) and fed by an array of slots in the ground plane for surface wave (SW) excitation, is considered. Cylindrical leaky wave (LW) radiation by the n = -1 spatial harmonic and perturbation of the TM₀ SW mode of the slab is achieved by the addition of a printed metallic grating. Attenuation and phase constants for the cylindrical LWmode are derived along with the pointing angle and beamwidth as a function of frequency. Results are also in good agreement with full-wave simulations and measurements for some recently designed and fabricated structures.