A Novel Fourier Series-Based Layout Optimization Approach for Arbitrary-Shaped Microstrip Networks

This letter proposes a novel layout optimization method for microstrip networks, which performs Fourier series decomposition on the planar closed curves representing the boundaries of microstrip networks and indirectly generates planar closed boundaries of microstrip networks with arbitrary shapes by adjusting the Fourier coefficients. The optimization of these Fourier coefficients is guided by a cost function calculated from circuit performance parameters. The proposed method can cover a large number of arbitrary microstrip boundary shapes using only a small set of parameters, and its boundaries are more continuous and smoother compared with those of traditional rectangle-based microstrip networks. This letter elaborates on the specific workflow of the method and presents three optimized design examples of microstrip matching networks for different scenarios.