A broadband circular waveguide-to-microstrip transition for an 80 GHz FMCW radar system

A simple, easy to integrate, and broadband circular waveguide-to-microstrip transition is presented in this paper. The transition, consisting of two mechanical parts and a high frequency laminate, can be realized in a standard manufacturing process and is particularly suited for high frequency applications. The development of a transition for a center frequency of 80 GHz is presented, allowing a good return loss and insertion loss in a bandwidth of more than 15 GHz, i.e. 19 %. 3D-electromagnetic field simulations are used for optimization and are compared to measurements of a first prototype to confirm the results and the functionality of the transition.