RF coupling to realistic wire systems in complex environments

Title from PDF of title page, viewed March 1, 2023Dissertation advisors: Ahmed M. Hassan and Anthony CarusoVitaIncludes bibliographical references (pages 117-130)Dissertation (Ph.D)--Department of Computer Science and Electrical Engineering, Department of Physics and Astronomy. University of Missouri--Kansas City, 2021With the continuous emergence of new wireless technologies, the possibility of unintentional electromagnetic interference (EMI) increases significantly. EMI coupling pathways to any Device Under Test (DUT) can be classified into two categories: front-door coupling and back-door coupling. Front-door coupling is interference through the DUT’s intended receiving elements such as antennas and sensors. In contrast, the back-door coupling is interference through cables, traces, and slots not intended for electromagnetic reception, which is more challenging to predict and mitigate. Back-door Radio Frequency (R.F.) coupling to a DUT depends on its orientation, environment, and the convoluted properties of its wires and linear/nonlinear load terminations. In this work, we adapted the Characteristic Mode Analysis (CMA) to quantify the variations in R.F. coupling with the DUT’s orientation. CMA decomposes the currents excited on the DUT by the impending electromagnetic waves in a set of fundamental modes. CMA is used to identify the significant modes within the frequency band of interest and the radiation characteristics of these modes. The orientations that maximize coupling to the DUT can be identified using these two factors. However, R.F. coupling also depends on both the wires and the electronic devices connected by these wires in the DUT. The Equivalent Circuit Approach (ECA) provides a unique solution to this complicated coupling problem by modeling the wires as a receiving antenna represented by a Thevenin equivalent circuit terminated with the linear/nonlinear load of interest. The advantages of the ECA are that it provides physical insight into the factors that dominate R.F. coupling at a fraction of the time needed by full-wave solvers. In this work, the CMA and the ECA are adapted to predict and guide coupling to a wide range of DUTs with progressively increasing complexity. Furthermore, we augment these computational modeling approaches with innovative experimental measurements to validate their predictions. To demonstrate the versatility of the developed techniques, we apply them for the first time to guide and predict EMI to practical Unmanned Aerial Vehicles (UAV) with realistic shapes, materials, and wire distributions. We conclude by showing how the coupling approaches developed can be adapted to predict/guide R.F. coupling to a wide range of DUTs.Introduction -- Characteristic mode analysis justification of the stochastic electromagnetic field coupling to randomly shaped wires -- Predicting electromagnetic interference to a terminated wire using characteristic mode analysis -- Characteristic mode analysis prediction and guidance of electromagnetic coupling measurements to a UAV model -- EMC analysis of quadcopter UAVs using equivalent circuit approach -- Quadcopter's frame material and shape effect on its electromagnetic compatibility, characteristic mode approach -- Conclusion and future researc