Efficient dispersion analysis of 2-D high-gain Leaky-Wave Antennas

A new simple and rigorous analysis technique is presented to derive the complex dispersion characteristics of periodic 2-D Fabry-Pérot Leaky-Wave Antennas (LWA). In order to illustrate the basics of the method an example involving a 2-D periodic array acting as a partially reflecting surface (PRS) situated at half-wavelength distance from a ground plane is utilised. The analysis procedure is based on a combination of array theory and periodic method of moments (MoM) yielding a fast and accurate calculation of the complex propagation constant of the leaky-mode of interest. Full-wave MoM together with reciprocity is employed for the estimation of the LWA radiation patterns at different frequencies from which the phase constant is determined. Subsequently, employing array theory the phase constant as calculated by MoM is used to estimate the radiation patterns. The leakage rate is obtained by simple matching of the resulting radiation patterns to those obtained using full-wave MoM. The technique is applicable to antennas with sub-wavelength profile where other techniques such as transverse equivalent network (TEN) lose accuracy.