Leaky-wave radiation at broadside from one-dimensional open periodic structures

Radiation at broadside from leaky waves is studied for one-dimensional periodic structures modeled by means of a transmission line periodically loaded by series or shunt loads. An asymptotic Bloch analysis of the equivalent network and a simple array-factor calculation of the radiated far field allows the derivation of conditions for achieving maximum power density radiated at broadside and beam splitting in terms of the dispersion properties of the corresponding leaky mode. The 3 dB frequency bandwidth for broadside radiation is characterized in terms of the leaky-pole locations in the complex plane and an approximate formula is provided. © 2005 IEEE