Fabrication and Characterization of Woodpile Waveguides for Microwave Injection in Ion Sources

In this article, we study the propagation of high-power RF fields along an air channel realized in a dielectric photonic crystal (PC) woodpile. The resulting hollow-core dielectric waveguide is suitable for high-power applications at 18 GHz and can be used as a dc-break for microwave ion sources. The infinite-periodic electromagnetic bandgap (EBG) waveguide structure has been truncated and coupled to a standard metallic rectangular waveguide operating in the fundamental TE10 mode. The fabricated waveguide structure exhibits a very low insertion loss (IL) of 0.5 dB over a transmission bandwidth of 260 MHz around the operating frequency of 18.25 GHz. A six-period structure has been manufactured, and the experimental characterization exhibits a very good agreement with the simulation results.