Characterization and Comparison of Formulas for Optimizing Broadside Radiation in a 2-D Leaky-Wave Antenna

Two-dimensional (2-D) leaky-wave antennas (LWAs) are commonly designed to radiate pencil beams at broadside and/or scanned conical beams. Recently, the possibility to radiate narrow null patterns at broadside has also been preliminarily explored. In this work, we first review the design rules to obtain a pencil beam from an infinite 2-D LWA and then show how they change for having a beam with a null at broadside. The effects of antenna truncation are also accounted for in both cases, and numerical results show how the optimum conditions are in turn affected.