Stub-loaded ridge waveguides for frequency-scanning antenna application

In this paper, we first investigate the structural parameters for recently developed leaky waveguide by Tsuji et al. (2005) to design a leaky-wave antenna with low sidelobes. Such an antenna requires to keep the phase constant the fixed value and then to vary the leakage constant over the wide range along an antenna axis. The guide structure under consideration includes many conductor edges at which the fields diverge, so its leakage characteristics are accurately calculated by the modified mode-matching method incorporating the singular field behavior into the aperture-field expressions. As an example, the antenna with the Taylor distribution of -30dB sidelobes is designed. Finally we investigate the excitation problem of this stub-loaded ridge guide and verify that the usefulness of both the coaxial feed for the present antenna structure and also the designed antenna from the numerical calculation.