Inverse Design Based on Coordinated Optimization of Multiport Excitation and Pixel Structure

Multiport electromagnetic devices are widely used in microwave systems, where performance is jointly governed by device structure and multiport excitation. Existing inverse-design approaches typically optimize either the pixelated structure or the excitation conditions separately, which limits achievable performance because structure and port excitations jointly affect the electromagnetic response. This work proposes a coordinated excitation–structure inverse-design method for multiport electromagnetic devices. Based on a field–circuit transformation framework, auxiliary discrete ports are introduced to equivalently represent the electromagnetic influence of pixelated structures as port load states, enabling a unified microwave-network description of excitation parameters, structural configurations, and electromagnetic responses. Within this framework, the structure configuration and multiport excitation amplitudes and phases are synchronously optimized, transforming the original field-level inverse-design problem into a tractable coordinated optimization in the network domain with reduced computational complexity. The proposed approach supports diverse design objectives, including scattering parameters, near-field distributions, and radiation patterns. Numerical and experimental studies on both guided-wave and free-space radiation systems demonstrate that the coordinated optimization consistently outperforms separated or sequential optimization strategies, achieving improved field control, radiation performance, and practical feasibility in multiport scenarios.