Performance analysis of multi hole directional coupler for different hole profiles

Abstract

The most critical and efficient circuits in guide wave single-mode systems are directional couplers. For Radio Frequency (RF) system designers, the directional coupler is a useful measurement unit. It offers not only an amplitude measured image of RF power levels but also identifies forward and reflected signal components to better characterize loads. They have been used in various telecommunications instruments, such as splitters, wavelength-dividing multiplexers, optical switches, etc. The paper streamlines the designing process of the waveguide coupler and its performance thereafter. The effects of hole shape and count for waveguide directional couplers are further investigated and compared in this study. The directional coupler with elliptical-shaped holes has been found to be more effective than its circular-holed counterpart. Also, compared to a coupler with circular holes, an elliptical hole directional coupler looks to be able to achieve high coupling with a reduced number of holes.