A 3 dB E‐plane waveguide directional coupler employing micromachining technique for terahertz application

Abstract

In this work, 3 dB branch‐line waveguide in the range of 335‐415 GHz directional coupler is proposed, where the insertion loss is less than 0.9 dB and the directionality is better than 20 dB. The coupler is composed of three “crossing”‐shaped structures, which can effectively enhance the directionality and coupling, based on a certain broad bandwidth. The designed coupler has been modeled and optimized, using commercial full‐wave simulation software HFSS, fabricated by the UV‐LIGA process. In addition, its deformation was theoretically analyzed at different pressures by ANSYS software to test its practicability. Both of the test and simulated results have a nice correlation. We conclude that our proposed coupler has excellent performance and can be used for the investigation of submillimeter wave components in terahertz applications.

Terahertz couplers based on branch lines and waveguide resonators

“…In the THz band, rectangular waveguides are preferred for their low loss compared to planar structures. Many THz component manufacturing technologies for waveguide structures have been proposed, such as computer numerical control milling (CNC), [1][2][3] photolithography process, 4 and deep reactive ion etching process. 5,6 However, as the size of the component decreases for the shorter wavelength, the tolerance for the fabrication process becomes increasingly tight.…”