Equivalent Circuit Modeling for Antenna Feed Networks in HPEM Environments

To study the mechanism of electromagnetic pulse coupling in wireless communication systems, it’s imperative to possess an effective equivalent receiving model for the antenna in high-power electromagnetic environments. Antennas typically integrate a nonlinear feed network designed to match the impedance between the coaxial cable and antenna radiators. However, in environments with strong electromagnetic pulse irradiation, the feed network can affect the pulse waveform entering the RF front-end circuit. Typically, only the physical structure parameters of the antenna radiator, such as its size, can be obtained, while the feed network’s structure and component parameters remain unknown. In this study, a blind parameter modeling method for constructing the equivalent circuit model of the antenna feed network is proposed. Consider antenna feed network is a separate two-port network in which the input side of the network consists of a high-voltage pulse source, a bounded wave antenna, and a target antenna radiator, while the output port is linked to the standard load. The input side model is established by simulation then, the equivalent circuit model parameters of the antenna feed network are subsequently optimized based on experimental data. Finally, the method is implemented in a shortwave antenna, where the antenna consists solely of a segment of the transmission line for feeding, in addition to the radiator. The optimization model is applied to obtain the coupling current of this antenna and the experimental verification is carried out. The results verify the effectiveness of the method.