A new approach employing scattering parameters (SPs) and genetic algorithm (GA) (SP-GA) is proposed for modelling conducted electromagnetic interference (EMI) noise source impedance. Based on the principle of SPs, the source impedance is measured through transmission and reflection parameters from a vector network analyser when the circuit is shorted and loaded with noise source impedance, respectively. Moreover, amplitude-frequency performance and phasefrequency performance are optimised by using GA, and therefore the equivalent resistance, capacitance, and inductance are attained following the usual formula of the phase and amplitude of source impedance. This work made contribution for the design of the conducted EMI filter.

UAVs have many functions in detection, fire protection, communication, etc. in modern life, but the complex electromagnetic environment has a very bad impact on the UAV communication link. In this paper, the BPSK modulation and demodulation method of the UAV downlink communication link was analysed. Some typical electromagnetic pulse models were established, including sinusoidal pulse, square wave pulse, triangular wave pulse, Gaussian noise, electric fast transient pulse and surge pulse. The amplitude of different electromagnetic pulses was analysed when UAV communication error rate achieve 5%. Furthermore, the influence on the transmission image quality via UAV downlink was analysed with different electromagnetic pulses, which will provide a theoretical basis for the anti-interference optimization design of UAV communication links in the future.

In view of the problem that the unmanned aerial vehicle (UAV) communication link is vulnerable to strong electromagnetic pulse generated by lightning or high‐voltage transmission lines in the complex electromagnetic environment, the influence of the electromagnetic pulse generated by the high‐voltage transmission line of the EFT electromagnetic pulse and the surge electromagnetic pulse on wireless communication link are analyzed in this paper. When those electromagnetic pulse's noise field strength is 500 V/m, the bit‐error‐rate of the communication link is increased to 45.39%, 45.39%, and 46.10%, respectively, indicating that surge pulse has the strongest influence on the communication link. Therefore, a UAV noise suppression method based on the principle of orthogonal frequency‐division multiplexing (OFDM) modulation and demodulation and dual antenna design has been proposed in this paper. This method is used to filter out electromagnetic impulse noise after wireless signal reception, and then demodulate to achieve the goal of noise suppression. Applying the method to a certain type of UAV based on OFDM modulation and demodulation, and theoretical analysis and simulation results show that the proposed method can effectively suppress the electromagnetic pulse generated by high‐voltage transmission lines, EFT electromagnetic pulse, surge electromagnetic pulse, the bit‐error‐rate dropped to 0.005597%, 0.004531%, 0.005597%, respectively.

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