Radio-Frequency design of a Lower Hybrid Slotted Waveguide Antenna

This paper presents a new type of slow-wave Lower Hybrid Current Drive launcher, based on the Slotted Waveguide Antenna (SWA) concept, which is particularly attractive for the use in future magnetic fusion reactors. A low power prototype SWA has been designed for the COMPASS tokamak at IPP-Prague. The Radio-Frequency (RF) design of this low power prototype is based on hybrid electromagnetic calculations, combining Finite-Element-Method, Mode Matching and RF network computations. Two SWA prototype samples have been manufactured with different slot geometries, and they have been first measured in air. The RF design of the low power SWA prototype and its feeding circuit is discussed in this manuscript; measurements in air are also illustrated.