Concise and Compatible MOR-Based Self-Adjoint EM Sensitivity Analysis for Fast Frequency Sweep

It is of great significance to perform adjoint electromagnetic (EM) sensitivity analysis when designing or optimizing a microwave component. Recent advances in adjoint EM sensitivity analysis using a fast frequency sweep have gained a considerable speedup over that using discrete frequency sweep. However, it needs complex computational loops for calculating the adjoint vectors, resulting in extra time for an increased number of forward/backward (F/B) substitutions of the original system matrix along with additional large matrix multiplications. The proposed method addresses this situation and proposes a novel model order reduction (MOR)-based self-adjoint EM sensitivity analysis for a fast frequency sweep. This method derives more concise and more compatible formulations for calculating adjoint sensitivities to decrease the number of F/B substitutions and matrix multiplications. The proposed method subsequently develops a new self-adjoint EM sensitivity analysis algorithm for a fast frequency sweep which further decreases half of the number of F/B substitutions. Compared with the existing adjoint sensitivity method for a fast frequency sweep, the technique we proposed can take less time due to the more concise sensitivity formulations while additionally obtaining better sensitivity accuracy in a relatively wide frequency range, especially when a higher MOR order is needed. Besides, the self-adjoint EM sensitivity analysis formulation can be compatible with various MOR techniques. Two EM examples of microwave components are used to demonstrate the proposed technique.