An EH₀-Mode Microstrip Leaky Wave Antenna on Differentially Excited Coupled Line for Transversal Single-Beam Radiation

Abstract

This communication presents a method to make the EH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> -mode microstrip leaky wave antenna (MLWA) radiate single beam in its transversal plane based on the differentially excited coupled microstrip line structure with low cross-polarization. The conventional EH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> -mode MLWA is constructed by periodically loading a series of shorting pins along the center line of the uniform line, but it mainly radiates dual beams in its transversal plane. If a ground plane approaches to one of its edges with rotation of the whole structure, only one radiation aperture will be left to radiate single beam in the broadside direction. Herein, a planar differentially excited coupled line configuration is implemented to validate the proposed method and simultaneously inherits the original outstanding characteristic of freely designed narrow strip width. In design, a unified equivalent model is first established to provide insight into its radiation principle through propagation characteristics. Then, the dispersion and radiation properties are further investigated under mixed geometrical parameters. Finally, a prototype MLWA with transversal single-beam radiation is designed and fabricated with good agreement between the simulated and measured results, which validates the proposed method for designing a single-beam EH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> mode MLWA.