Design and fabrication of X-band Substrate Integrated Waveguide directional coupler

The compact size of four-port Substrate Integrated Waveguide (SIW) directional coupler designed for X-band application have been simulated and fabricated. The millimeter-wave circuits such as resonator, filter, coupler, power divider and the antenna can be designed by using SIW techniques. This technique appears the past few years and having the smaller size of circuits. It can straightforwardly integrate with the other planar circuit. Ordinary Printed Circuit Board (PCB) method can be utilized in order to complete the fabrication process. The cost of the manufacturing process for SIW is lower compared by using conventional waveguide. Usually, implementation of the directional coupler can be seen at satellite, radar and point-to-point radio. The simulations and measurement of this coupler design have shown the great performances by having the low insertion loss and return loss. Moreover, it also has high isolation and broad operational bandwidth.