Design of wideband coaxial-TEM to circular waveguide TM01 mode transducer

Coaxial TEM to circular waveguide TM01 mode transducer designs with wide bandwidth and compact size are presented in this paper. The coaxial feed with its centre conductor extended as a cone, is applied at the axis of a circular waveguide. Further modifications in the conical shape monopole are proposed (skirt and inverted cone), which result in a wide bandwidth (28.5% and 33.8% respectively) of TM01 mode excitation in a circular waveguide. Many of the High Power Microwave (HPM) sources generate output signal in the form of TM01 mode of circular waveguide. The proposed transducer is useful for low power calibration of an antenna or a mode converter designed for high power microwave applications.