Research on Tensor CSAMT Pattern Synthesis and Adaptive Beamforming Based on L-Shaped Array Artificial Field Source

Traditional CSAMT omnidirectional radiation causes low energy efficiency, while near-field effects and far-field interference limit detection accuracy. To address the issues of energy dispersion, low signal-to-noise ratio, and restricted exploration range in conventional Controlled Source Audio-frequency Magnetotelluric (CSAMT) methods for deep exploration, this paper proposes a tensor CSAMT directional pattern synthesis and adaptive beamforming method based on an L-shaped array artificial field source. An L-shaped source composed of two orthogonal coaxial dipole linear arrays is designed, and Taylor-weighted directional pattern synthesis is employed to reduce sidelobe levels. An adaptive beamforming system is constructed based on the maximum Signal-to-Noise Ratio criterion to achieve dynamic beam steering and energy focusing. Verified via COMSOL simulations and field experiments, this study upgrades the CSAMT artificial source from "omnidirectional radiation" to "directional and controllable" using array antenna technology, providing a high signal-to-noise ratio and efficient electromagnetic detection paradigm for deep resource exploration.