Experimental demonstration of the effect of groove shape on the wave properties of the helical groove waveguide

This letter presents a simple and general fabrication method for helical groove waveguides (HGWs) with successful fabrication of a number of novel HGWs such as the hole-gap-shaped groove HGW, the swallow-tailed groove one, the trapezoid groove one and the ridge-loaded rectangular one. Also, measurements on these structures have been carried out to determine their dispersion properties. The experimental results agree well with the theoretical results and demonstrate the large influence of groove shape on the dispersion characteristics of the structures.