Design and Measurement of Power-Coupling Structure for Parallel Operation of Two Folded Groove Waveguides

Abstract

In this article, we design an input–output energy-coupling method for the parallel operation of two terahertz folded groove waveguides (FGWs)—a conversion from TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sub> mode to two modes of TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> . The mode is first converted in the H-plane of standard waveguide WR4 from TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sub> to TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> , and which is then subsequently converted into two TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> modes through a Y-branch step impedance transformation. The novel energy-coupling structure was manufactured and measured so that the S parameter <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{S}_{{11}}$ </tex-math></inline-formula> is less than −10 dB in the frequency range of 170–260 GHz. And in the frequency range of 190–250 GHz, the simulated and measured transmission coefficient <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{S}_{{21}}$ </tex-math></inline-formula> tends to be consistent. Moreover, using the coupling structure, the dispersion characteristics of the parallel operation of two FGWs was measured.