Folded Parallel Plate Waveguide Launcher for Surface Wave Antennas at Ku-Band

This paper presents a novel design of a folded parallel plate waveguide launcher. A low height overmoded waveguide is adopted making the structure low loss and compact. The waveguide generates a quasi-TEM wavefront to feed radiating structures based on surface waves, such as leaky wave or metasurface antennas. The height of the fold can be adjusted accordingly. As a design example, results of two folded structures having heights 10mm and 17mm is shown here. Also, to show the functionality of the structure, the launcher is integrated with a n-furcated divider and a taper to connect to a standard waveguide flange. The designed feeding part works well in the Ku band with a return loss below -18dB from 11.7 to 13.1 GHz and a suppression of higher modes is achieved below -15dB for most of the band resulting in a quasiTEM mode.