Two-Channel Metal Detector Using Two Perpendicular Antennas

<table>Detection limit of metal sensor: (a) <svg height="11.375" id="M86" style="vertical-align:-0.17555pt" version="1.1" viewbox="0 0 53.387501 11.375" width="53.387501" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
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</svg> mm ferrous test ball (<svg height="11.375" id="M87" style="vertical-align:-0.17555pt" version="1.1" viewbox="0 0 47.412498 11.375" width="47.412498" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
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</svg> mV/div, <svg height="11.375" id="M88" style="vertical-align:-0.17555pt" version="1.1" viewbox="0 0 57.487499 11.375" width="57.487499" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
<g transform="matrix(.017,-0,0,-.017,.062,11.112)"><path d="M775 650l-6 -28q-60 -6 -81.5 -16t-61.5 -54l-175 -191l125 -243q30 -58 48.5 -71t82.5 -19l-5 -28h-275l7 28l35 4q31 4 37 12t-6 34l-108 216q-140 -165 -177 -219q-16 -22 -10.5 -30.5t41.5 -13.5l22 -3l-7 -28h-244l8 28q52 4 75 15.5t67 52.5q48 46 206 231
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</svg> ms/div), (b) <svg height="11.375" id="M89" style="vertical-align:-0.17555pt" version="1.1" viewbox="0 0 53.387501 11.375" width="53.387501" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
<g transform="matrix(.017,-0,0,-.017,.062,11.112)"><path d="M780 372q0 -191 -178 -297q-128 -75 -335 -75h-250l7 27q61 7 77 22t28 76l77 398q11 62 0 76.5t-77 22.5l6 28h292q164 0 258.5 -67.5t94.5 -210.5zM678 375q0 119 -73 180.5t-201 61.5q-62 0 -82 -13q-17 -7 -25 -53l-80 -427q-8 -47 -4 -62t26 -20q24 -6 80 -6
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</svg> mm ferrous test ball (<svg height="11.375" id="M90" style="vertical-align:-0.17555pt" version="1.1" viewbox="0 0 47.412498 11.375" width="47.412498" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
<g transform="matrix(.017,-0,0,-.017,.062,11.112)"><path d="M667 650l-9 -28q-53 -5 -76 -17t-64 -59q-51 -61 -175 -225q-21 -29 -27 -55l-27 -136q-13 -65 -0.5 -80t83.5 -22l-7 -28h-280l8 28q64 4 81 19t30 83l25 128q6 35 -7 65l-98 231q-17 41 -32.5 52t-68.5 16l8 28h252l-6 -28l-40 -4q-27 -3 -33 -12.5t2 -31.5
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</svg> mV/div, <svg height="11.375" id="M91" style="vertical-align:-0.17555pt" version="1.1" viewbox="0 0 57.487499 11.375" width="57.487499" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
<g transform="matrix(.017,-0,0,-.017,.062,11.112)"><path d="M775 650l-6 -28q-60 -6 -81.5 -16t-61.5 -54l-175 -191l125 -243q30 -58 48.5 -71t82.5 -19l-5 -28h-275l7 28l35 4q31 4 37 12t-6 34l-108 216q-140 -165 -177 -219q-16 -22 -10.5 -30.5t41.5 -13.5l22 -3l-7 -28h-244l8 28q52 4 75 15.5t67 52.5q48 46 206 231
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</svg> ms/div).</table>

Journal of Sensors

Two-Channel Metal Detector Using Two Perpendicular Antennas

Figure 17