Alternative Near-Field Gradient Probe For The Suppression Of Radio Frequency Interference

Abstract

A sensor probe. The probe includes a central loop and a plurality of peripheral loops disposed peripherally relative to the central loop. To maximize far-field suppression, current flows in a first direction through the central loop and in a second direction through each one of the plurality of peripheral loops, the first direction opposite to the second direction, and current through the central loop equals current through the plurality of peripheral loops.

What is claimed is: 
     
         1 . A sensor probe comprising:
 a conductive central loop;   a plurality of conductive peripheral loops disposed peripherally relative to the central loop; and   the central loop and the plurality of peripheral loops configured such that current flows in a first direction through the central loop and in a second direction through each one of the plurality of peripheral loops, the first direction opposite to the second direction, and wherein current through the central loop equals current through the plurality of peripheral loops.   
     
     
         2 . The sensor probe of  claim 1 , wherein an area of the central loop is equal to a sum of an area of each one of the plurality of peripheral loops. 
     
     
         3 . The sensor probe of  claim 1 , wherein a product of an area of the central loop and the current through the central loop equals a product of an area of the plurality of peripheral loops and a current through the plurality of peripheral loops. 
     
     
         4 . The sensor probe of  claim 1 , wherein a shape of the central loop, and a shape of each one of the plurality of peripheral loops comprises a same closed geometric figure, the same geometric figure further comprising a polygon or a circle. 
     
     
         5 . The sensor probe of  claim 1 , wherein the plurality of peripheral loops comprises four, five, nine, or seventeen peripheral loops. 
     
     
         6 . The sensor probe of  claim 1 , wherein the plurality of peripheral loops comprises a first, second, third, and fourth peripheral loop, the sensor probe further comprising a fifth, sixth, seventh, and eighth peripheral loop each paired with a respective first, second, third, and fourth peripheral loop, wherein a sum of an area of each one of the first through eighth loops equals an area of the central loop. 
     
     
         7 . The sensor probe of  claim 1 , wherein the central loop and the plurality of peripheral loops are each defined by a perimeter and oriented such that a perimeter segment of each peripheral loop is proximate a perimeter segment of the central loop, and the peripheral loops are spaced equally around the central loop. 
     
     
         8 . The sensor probe of  claim 1 , wherein a distance between a center of the central loop and a center of each one of the plurality of peripheral loops is less than about 5% of a wavelength of signals impinging the sensor probe. 
     
     
         9 . The sensor probe of  claim 1 , wherein an interior region of each one of the plurality of peripheral loops overlaps an interior region of the central loop. 
     
     
         10 . The sensor probe of  claim 1 , wherein a shape of the central loop is congruent with a shape of each one of the plurality of peripheral loops. 
     
     
         11 . The sensor probe of  claim 1 , wherein the plurality of peripheral loops is equally spaced peripherally relative to the central loop. 
     
     
         12 . The sensor probe of  claim 4 , wherein the polygon has eight or more sides.