Direct Machining of Low-Loss THz Waveguide Components With an RF Choke

Samantha M Lewis; Emilio A Nanni; Richard J Temkin

doi:10.1109/LMWC.2014.2303161

Direct Machining of Low-Loss THz Waveguide Components With an RF Choke

IEEE Microw Wirel Compon Lett. 2014 Dec 1;24(12):842-844. doi: 10.1109/LMWC.2014.2303161.

Authors

Samantha M Lewis¹, Emilio A Nanni², Richard J Temkin³

Affiliations

¹ Department of Nuclear Science and Engineering and the Plasma Science and Fusion Center (PSFC), Massachusetts Institute of Technology, Cambridge, MA 02139 USA.
² Department of Electrical Engineering and Computer Science and the PSFC, Massachusetts Institute of Technology, Cambridge, MA 02139 USA.
³ Department of Physics and the PSFC, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.

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.

Keywords: Direct machining; THz; fabrication; millimeter wave; split-block; waveguide.

Abstract

Grants and funding