Deembedding and Optimization of a Decoupling Structure Using a Modal Coupling Matrix

A workflow to optimize a decoupling structure that is placed between the transmit and receive subarray of a mono-static sensing array is presented. A modal coupling model based on generalized scattering matrices in terms of characteristic modes is used to deembedd the decoupling elements from their environment. Based on this model, an iterative workflow for the optimization of the elements is derived. To represent the degrees of freedom during the design of the decoupling elements, the modal scattering behavior of the decoupling elements is synthetically modified in the model. The manopt toolbox is used to find the optimal configuration of the decoupling elements using an approximate model and full-wave simulations are only used sparingly to obtain accurate results, which reduces the simulation time to find optimal results. The finally obtained decoupling structure shows a reduction of the coupling by 17 dB.