Design and Calibration of the Wide-Band Three-Component Air-Core Coil Sensor for Shallow Target Detection

The wide-band three-component air-core coil sensor can effectively collect multiple components of electromagnetic signals, enabling the observation of synthetic magnetic fields. This paper proposes measures to widen the frequency band of the coil sensor by studying the equivalent circuit model and physical structure of the induction coil, including reasonable size design and adding fillers. A rapid damping matching method for air-core coils was designed, and a three-component orthogonal structure was developed using a lightweight foldable framework. Actual measurements show that the resonance frequencies of the three sub-coils all reached above 85 k, making them applicable for shallow target detection.