Overmoded corrugated waveguide is efficient at transmitting power over a large frequency bandwidth. This operational flexibility becomes important in multi-frequency systems. For 50-mm diameter aluminum corrugated waveguide nominally designed for the ITER 170 GHz ECH system, the theoretical ohmic loss of the HE11 mode is around 0.3e-3 dB/m. In a possible dual-frequency system at ITER, the theoretical loss in the same waveguide increases to a manageable 0.8e-3 dB/m at 104 GHz. As examples of other wideband components, General Atomics has built several pairs of 63.5-mm diameter waveguide polarizers for the TCV tokamak's ECH transmission line that are designed to operate for 1 MW at frequencies ranging from 82.6 to 118 GHz. In addition, polarizers have been designed for ITER's 50-mm diameter transmission line. A computer code that calculates both the required mirror rotation angles and the ohmic losses predicts that these polarizers will function effectively at both 170 GHz and 104 GHz. A new class of wideband waveguide switches with rotary actuators have been supplied for the 82.6-126 GHz transmission lines at TCV, further emphasizing the broadband capabilities of corrugated waveguide components.

This paper provides an overview of high power components for the application of Electron Cyclotron Heating transmission lines, and broadband devices for Electron Cyclotron Emission detection systems. The unique fabrication and assembly challenges are discussed, particularly in the context of ITER. The ITER ECH system will require robust, vacuum-compatible components such as polarizers, dummy loads, and switches that are sufficiently cooled to withstand 1 MW for 3,600 seconds. These elements, along with overmoded corrugated waveguide, are necessary to form transmission lines with efficiencies of 90%, and 90% transmitted HE11 mode purity. Recent high power test results are summarized and scaled from the 63.5 mm internal diameter design to the 50 mm diameter version that will be used for ITER. Elements designed for Electron Cyclotron Emission detection and reflectometry systems are discussed, such as frequency filters and polarization rotators. The large frequency operating range of corrugated waveguide is exploited for such applications. The application of additive manufacturing technology towards both low and high power components is considered as a promising new area of development.