A left-handed/right-handed leaky-wave antenna derived from slotted rectangular hollow waveguide

A low-profile leaky wave antenna based on a composite left-handed/right-handed substrate integrated waveguide is presented. It utilizes the fact, that the H₁₀ rectangular hollow waveguide mode can be represented by a lumped element equivalent circuit model, where only the series capacitor is missing as compared to the lumped element equivalent circuit model of a composite left-handed/right-handed transmission line. The series capacitor is realized by transverse slots in the upper major side of the waveguide, which are bridged by metallic strips located in a plane slightly below the upper side. Thus, sufficiently large capacitors can be realised and the periodic sections can be kept relatively short as compared to the wavelength. Moreover, the open configuration exhibits parasitic radiation leading to the leaky-wave antenna. Simulation results show an antenna with high efficiency and good matching to a 50 Omega microstrip line over a wide bandwidth, where backward and forward scanning as well as broadside radiation with an achieved maximum gain up to 10.15 dBi is possible dependent on the chosen operation frequency.