title: Direct Machining of Low-Loss THz Waveguide Components With an RF Choke.
abstract: We present results for the successful fabrication of low-loss THz metallic waveguide components using direct machining with a CNC end mill. The approach uses a split-block machining process with the addition of an RF choke running parallel to the waveguide. The choke greatly reduces coupling to the parasitic mode of the parallel-plate waveguide produced by the split-block. This method has demonstrated loss as low as 0.2 dB/cm at 280 GHz for a copper WR-3 waveguide. It has also been used in the fabrication of 3 and 10 dB directional couplers in brass, demonstrating excellent agreement with design simulations from 240-260 GHz. The method may be adapted to structures with features on the order of 200 μm.
authors.affiliation: Department of Nuclear Science and Engineering and the Plasma Science and Fusion Center (PSFC), Massachusetts Institute of Technology, Cambridge, MA 02139 USA.
authors.forename: Samantha M
authors.initials: SM
authors.lastname: Lewis
authors.affiliation: Department of Electrical Engineering and Computer Science and the PSFC, Massachusetts Institute of Technology, Cambridge, MA 02139 USA.
authors.forename: Emilio A
authors.initials: EA
authors.lastname: Nanni
authors.affiliation: Department of Physics and the PSFC, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Temkin
keywords: Direct machining; THz; fabrication; millimeter wave; split-block; waveguide
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