Numerical Modeling of Millimeter-Wave Transmission Lines

The transmission of high-power millimeter waves for electron cyclotron resonance heating of plasmas is a well-developed field that has reached a mature level over the years. The design goals are low transmission losses, high mode purity, and arbitrary polarization adjustment with low cross-polarization. Quasi-optical and waveguide techniques are at hand for the design of transmission lines, which, in most cases, are a combination of both approaches. This paper discusses the efficient numerical processing of paraxial beams and fields in oversized corrugated waveguides including polarization, and how these methods can be used for the analysis, synthesis, and modeling of the RF fields from the gyrotron cavity to the plasma.