Full-wave analysis of radiation properties of microstrip leaky-wave arrays

In this work, a comprehensive study of linear arrays of microstrip leaky-wave antennas is presented. By means of a rigorous spectral-domain formulation in the unit cell, the dispersion properties of the leaky modes excited along the antenna elements are derived. This analysis allows us to perform a complete characterization of the radiation features of this class of leaky-wave arrays as a function of both frequency and array phasing. In particular, bidimensional scanning behaviour, variation of the beamwidths in elevation and azimuth, and occurrence of grating lobes are investigated. The presented study furnishes useful insights aimed at the synthesis of microstrip antenna arrays with assigned performance. Comparisons with full-wave simulations on finite arrays demonstrate the accuracy and the efficiency of our analysis based on the dispersion properties of the involved leaky modes.