Simulation-Inserted Optimization of Fourth-order Waveguide Filter Using Combined Lagrangian Method With Newton’s Method

Gradient-based optimization methods are popular in electromagnetic (EM)-based design. In the gradient-based methods, Newton’s method can hardly apply to direct EM optimization as calculating the Hessian matrix containing the second-order derivatives of the EM responses w.r.t. the geometrical variables is very time-consuming. The simulation-inserted optimization (SIO) method using the combined Lagrangian method with Newton’s method for EM optimization has been proposed. The SIO method can optimize and converge faster than other gradient-based optimization methods. This paper aims to apply the SIO method to optimize a fourth-order hybrid waveguide filter.