Ohmic Loss Reduction in Highly Overmoded Iris Lines Using Chisel-Edged Screens

In this note, we report observations on the growth trends of diffraction power loss and ohmic power loss, as functions of screen thickness, in highly overmoded THz or mm-wave iris-line waveguides that are constructed from finitethickness screens. Recent theoretical developments have given a detailed field description, including eigen and transient analyses, that characterizes such waveguides under paraxial dipole-mode excitation. Informed by these analyses, we can better estimate, and minimize, power-loss effects due to finite screen thickness in practical realizations. A geometric variation with chisel-edged screens is proposed whereby we limit the growth trend in ohmic loss, even when using relatively thick screens in practice.