Yield-driven design of direct-coupled waveguide filters with minimum use of full wave EM solvers

To reduce costly prototyping and allow for short design cycles in the design of tuningfree waveguide filters, it is important to be able to perform yield analysis in short time frames. For many filter topologies, this is infeasible by direct application of full wave EM solvers. In this paper, a simple and fast method for yield-driven design of direct-coupled waveguide filters with minimum use of full wave EM solvers is presented. The method is based on training a circuit model by including the sensitivities of each coupling to changes in dimensions and frequency. It is shown that this model gives accurate results for dimensional changes within typical production tolerances for waveguide components, and it is thus possible to perform fast tolerance analysis with high accuracy for yield-driven design. Examples of tolerance analysis for some filter topologies are shown. Also included is a comparison with measurements.