Experimental study of a perforated coaxial exciter of high-order modes in a barrel-shaped cavity

A method proposed previously 1], according to which high-order modes in a barrel-shaped cavity are selectively excited using a coaxial waveguide with a double periodic perforation of the wall, has been experimentally realized. A rotating H₁₁ waveguide mode has been converted into a rotating H₅₃₁ eigenmode with a conversion efficiency of about 98%.