A Millimeter Wave High-Order TE₁₃ Mode Converter

Abstract

In this paper a methodology to excite a circular high-order TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">13</sub> -mode via a rectangular TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">50</sub> mode was proposed and verified by the millimeter wave measurement. This topology can also be applied to launch other high-order modes (HOMs) such as TE <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{1n}$ </tex-math></inline-formula> , TE <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{2n^\prime }$ </tex-math></inline-formula> and TE <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{0n^\prime }$ </tex-math></inline-formula> (n or <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$n^\prime =1$ </tex-math></inline-formula> , 2, 3) modes via different transition rectangular TE <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{m0}$ </tex-math></inline-formula> ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$m = 2n-1$ </tex-math></inline-formula> or <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$m = 2n^\prime $ </tex-math></inline-formula> ) modes, which can be achieved by adjusting the number of coupling apertures and optimizing dimensions of tapered waveguides. A W-band TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">13</sub> mode converter was designed and analyzed. Two identical converters connected back to back as a proof-of-principle operating at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Q$ </tex-math></inline-formula> -band were fabricated and measured. Good performance was observed, which was in good agreement with the simulation results. This HOM converter has many potential applications in areas such as gyro-devices, high-power transmission lines, RF multimode systems of accelerators, microwave/plasma, and antenna systems.