Balanced Metal Detector Based on Optimized Frequencies and Spatial Phase Profile Responses to Differentiate Metal Rods

Inductive detection with double-balanced coils and a spatial phase profile were used to identify copper and steel rods in a composite target. The electromagnetic detection system was designed and validated with a dipole model. Simulations and experiments identified whether a target was copper, steel, or a combination. The system, optimized for excitation at high audio frequencies, was able to estimate the sizes, depths, and locations of the target materials.