A Hybrid FDTD-SPICE Method for Predicting the Coupling Response of Wireless Communication System

This article presents a hybrid finite-difference time-domain-simulation program with integrated circuit emphasis (FDTD-SPICE) method for analyzing the system-level coupling responses of the wireless communication system with antenna, metallic enclosures, braided shielded cable, and lumped element, when illuminated by an external electromagnetic pulse (EMP). In the hybrid method, a system-level SPICE model combining antenna and braided coaxial cable is proposed to predict the coupling effects including front-door and back-door couplings. FDTD is used to calculate the induced current on the outer conductor of the coaxial cable, which is then incorporated into the system-level SPICE model as an additional current source. Because the hybrid method avoids meshing the antenna and cable, it has higher computational efficiency than full-wave analysis. A typical microstrip antenna system is selected as a case to demonstrate the accuracy and effectiveness of this proposed method by comparing the numerical results with those obtained by CST. Then, considering the influence of the incident conditions of external EMP, the coupling voltages of the microstrip antenna system are calculated. Furthermore, a typical filter circuit is analyzed to illustrate the practicability of the proposed method. The obtained coupling response information demonstrate that the proposed method is available for designing electromagnetic protection of the inner circuits of the wireless communication system against the impact of external incident wave.