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Journal of Sensors
Volume 2014 (2014), Article ID 412621, 11 pages
http://dx.doi.org/10.1155/2014/412621
Research Article

Two-Channel Metal Detector Using Two Perpendicular Antennas

Department of Information and Telecommunication Engineering, Incheon National University, Incheon 406-772, Republic of Korea

Received 6 March 2014; Revised 14 June 2014; Accepted 23 June 2014; Published 10 July 2014

Academic Editor: Ignacio R. Matias

Copyright © 2014 Kyoo Nam Choi. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Two-channel metal detector, having two sets of perpendicularly oriented sensor antennas, is proposed to expand detectable size, ranging from mm through cm scale, of metal sensor, while conventional metal sensor is dedicated for detection only in mm or cm scale. The characteristics of the two metal detection sensor channels were investigated, respectively, and the interference effect, while in simultaneous operation, between two sensor channels was discussed. Metal detection channel, having sensitivity in mm scale, showed detectable sensitivity to moving ferrous sphere, with diameter down to 0.7 mm, at 50 kHz exciting frequency and enhanced sensitivity distribution. And metal detection channel having sensitivity in cm scale showed more uniform sensitivity distribution with the flexibility for future modular construction. The effect of interference, while in simultaneous operation of two sensors, resulted in reduced output response, but still within usable detection range. Thus it was feasible to operate two sensors, having different sensitivity range, simultaneously and to extend detection range from mm to cm scale, within practically acceptable interference.