Numerical Synthesis Method of a Dual Frequency Waveguide Directional Coupler for Miter Bend

A numerical synthesis method of the waveguide direction coupler(WGDC) for the miter bend is proposed in this paper. The concept of the synthesis method stems from the diffraction grating, which allows pattern control with the arbitrary incident angle when the waveguide operates at dual frequency. As an example, a power monitor has been designed for a 28/35GHz coupler with an incident angle of
$55^{\circ}$
. An arrangement of the holes array has been obtained to get the desired array pattern at a given angle, and the directivity of the power monitor is larger than 40dB at 28/35GHz.