A spectral domain approach for computing the radiation characteristics of a leaky-wave antenna for millimeter waves

A new method for evaluating the complex propagation constant
\beta
in a leaky-wave structure comprising thin metallic rectangular strips etched on a dielectric rod of rectangular cross section is described. The radiation pattern of the leaky-wave antenna can be determined once
\beta
is known, since Re(
\beta
) governs the direction of the main beam and Im(
\beta
) accounts for the beamwidth and aperture efficiency. In addition the knowledge of the dependence of
\beta
on frequency allows one to design the antenna for frequency-scanning applications. The method employed in this communication is based on the spectral domain approach that formulates the eigenvalue problem in the Fourier transform domain. Computed results are shown to be in very good agreement with experimental measurements.