Optimization Design of Continuous Wave-Illuminated Antenna Based on Scattering Parameter Analysis

This paper addresses the computational inefficiency of reflection coefficient calculation for loaded antennas under Continuous-Wave (CW) electromagnetic illumination. A rapid calculation method based on multi-port network S-parameters is proposed. By establishing a network model incorporating radiation and load ports, the loaded antenna system is characterized as a scattering parameter matrix. Under the premise of maintaining invariant network topology, this method enables rapid re-calculation of reflection coefficients through updating load parameters only, effectively avoiding repetitive full-wave simulation modeling in conventional approaches. A genetic algorithm optimization framework is subsequently developed based on this methodology, successfully designing an elliptical illuminator antenna with near-field horizontally polarized plane-wave simulation characteristics. Simulation results demonstrate that the optimized antenna achieves VSWR below 2.7 across the 0.1 MHz-30 MHz operational bandwidth, while the dominant polarization component of the electric field in the test area satisfies ≥0.1 V/m (0.1 MHz-1 MHz) and ≥1 V/m (1 MHz-30 MHz), fully complying with the IEC 61000-4-23 illumination compliance thresholds.