Effect of wall thickness on broadband design of a Ka-band TE21-mode coupler

Abstract

Commonly, the classical formulas for designing TE21-mode coupler are suitable for the operating frequency under Ka-band by virtue of ignoring wall thickness. However, in real application of TE21-mode coupler design beyond Ka-band, the new formulas need to consider the effect of wall thickness. Herein, we demonstrate a design measure of a TE21-mode coupler beyond Ka-band via computer simulation, giving attention to wall thickness. The experimental results show that a measure of linear second weighted sum for coupling hole size could improve coupler performance. Amazingly, such coupler shows 10% bandwidth with less than 0.5 ​dB coupling loss and more than 40 ​dB isolation is possible.