An integrated quasi-planar leaky-wave antenna

A new quasi-planar leaky-wave antenna is presented. It consists of microstrip line on one side of the substrate and uniplanar circuit on the other side placed in a partially opened waveguide. The leakage is produced by the excitation of the first higher order (odd) microstrip mode coupled electromagnetically through a slotline on the opposite side of the substrate. Theoretic results based on rigorous Green's impedance integral equation method show that the new microstrip-slotline-coupled leaky-wave antenna has a broadband tuning range via structure parameters and is insensitive to the microstrip line width variation. Measured relative power absorbed (RPA) results indicate that the useful frequency bandwidth agrees with that predicted by rigorous field theory. The measured antenna radiation patterns also agree very well with the approximate theoretic computations. The theory and experiments show that the proposed leaky-wave antenna can interface to feeding structure easily and directly. The new antenna may become a good candidate for microwave and millimeter-wave integrated antenna design