Simulation and design of ridge waveguide coupler

The design of a ridge waveguide coupler and a transition from coaxial line to ridge waveguide are addressed in this contribution, this types of directional couplers are commonly used by their compact size in comparison with other waveguide configurations. The design has been simulated using CST Microwave Studio 3D simulator, the simulation shows that the return loss of ridge waveguide couplers is below -24dB between 5.8GHz and 7.25Ghz, and the isolation is better than 29dB in the design band, the coupling is 7.13±0.2dB, the direct-side power is 0.93±0.02dB. the cross-sectional area of port is 33% of the standard rectangular waveguide, the relative bandwidth is 22%. In order to match the ridge waveguide, this paper presents the design of a transition from coaxial line to ridge waveguide, the return loss is below -22dB in the design band.