Active induction balance method for metal detector sensing head utilizing transmitter-bucking and dual current source

7th Sensors & their Applications

Ambru, D.^1 ; Vasic´, D.^1 ; Bilas, V.^1

University of Zagreb, Faculty of Electrical Engineering and Computing FER-ZESOI, Unska 3, HR-10000 Zagreb, Croatia^1

关键词: Detection sensitivity;    Effective suppression;    Electromagnetic induction sensors;    Geometrical property;    Inductive couplings;    Sensor dimensions;    Small perturbations;    Spatial resolution;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/450/1/012047/pdf
DOI  :  10.1088/1742-6596/450/1/012047

来源: IOP

【 摘 要 】

A central problem in a design of frequency domain electromagnetic induction sensors used in landmine detection is an effective suppression of a direct inductive coupling between the transmitter and the receiver coil (induction balance, IB). In sensing heads based on the transmitter-bucking configuration, IB is achieved by using two concentric transmitter coils with opposing exciter fields in order to create a central magnetic cavity for the receiver coil. This design has numerous advantages over other IB methods in terms of detection sensitivity, spatial resolution, sensor dimensions and suitability for model-based measurements. However, very careful design and precise sensing head geometry are required if a single excitation source is used for driving both transmitter coils. In this paper we analyze the IB sensitivity to small perturbations of geometrical properties of coils. We propose a sensor design with dual current source and active induction balance scheme which overcomes the limitations of geometry-based balancing and potentially provides more efficient compensation of soil effects.