Waveguide coupler design and fulfillment

This article is a detailed introduction to the single aperture waveguide coupler which realizes the basic principle of two-port outputs. According to the aperture coupling theories, we deduced the mathematical expression between the coupling coefficient and the size of the aperture. Using the expression, we´ve calculated the coupling coefficient theoretical value when a certain size of the aperture is given and the aperture deviates from the center producing different angles of inclination. The result of experiment of a trial sample shows that the difference between the coupling coefficient theoretical value and the actual measured value is less than 5%.