Analysis of a Microstrip Leaky-Wave Antenna Loaded with Shorted Stubs

A new theory is provided to analyze a novel microstrip leaky-wave antenna (MLWA) with shorted stub loading, used for fixed-frequency beam steering applications. Formulas for calculating the radiation angle of MLWA with stub loading are deduced. The radiation angle estimated theoretically agrees very well with the rigorous numerical result calculated with the finite difference time domain (FDTD) method. This new theory can be used to explain the MLWA behavior with any reactive element loading, if the input admittance of the reactive element is known.