« AnteriorContinuar »
United States Patent [i9] [n] Patent Number: 5,038,104
Wikswo, Jr. et al.  Date of Patent: Aug. 6, 1991
 MAGNETOMETER FLUX PICK-UP COIL
WITH NON-UNIFORM INTERTURN
SPACING OPTIMIZED FOR SPATIAL
 Inventors: John P. Wikswo, Jr., Brentwood,
Tenn.; Bradley J. Roth, Kensington,
 Assignee: Vanderbilt University, Nashville,
 Appl. No.: 475,171
 Filed: Feb. 5, 1990
 Int. CI.' G01R 33/035; G01R 33/10
 U.S. CI 324/258; 324/248;
324/261; 336/224; 505/845
 Field of Search 324/248, 260, 258, 239,
324/243, 262; 336/224; 505/705, 845
 References Cited
U.S. PATENT DOCUMENTS
4,453,067 6/1984 Karklys et al. .
4,490,426 5/1986 Lutes .
4,517,540 5/1985 McDougal .
4,585,999 4/1986 Hilbert et al. .
4,593,245 6/1986 Viertl et al. .
4,613,817 9/1986 Hoenig 324/248
John P. Wikswo, Jr., Optimization of Squid Differential Magnetometers, Future Trends in Superconductive Electronics, AIP Conference Proceedings, No. 44, pp. 145-149, 12/1978.
John P. Wikswo, Jr., et al., Magnetic Determination of the Spatial Extent of a Single Cortical Current Source: A Theoretical Analysis1, Electroencencephalography
and Clinical Neurophysiology, 12/1988, 69: 266-279,
Elsevier Scientific Publishers Ireland, Ltd.
John P. Wikswo, Jr., High-Resolution Measurements
of Biomagnetic Fields, Advances in Cryogenic Engineer-
ing, vol. 33, Plenum Publishing Corporation, 12/1988,
Bradley J. Roth et al., Using a Magnetometer to Image
A Two-Dimensional Current Distribution, J. Appl.
Phys., 65(1), Jan. 1, 1989, pp. 361-372.
S. Evanson et al., A Comparison of the Performance of
Planar And Conventional Second-Order Gradiometers
Coupled to a Squid for the NDT of Steel Plates, IEEE
Transactions on Magnetics, vol. 25, No. 2, Mar. 1989,
A. C. Bruno et al., Discrete Spatial Filtering with Squid
Gradiometers in Biomagnetism, J. Appl. Phys., 59(7),
Apr. 1, 1986, pp. 2584-2589.
R. Turner, A Target Field Approach to Optimal Coil Design (Letter to the Editor), J. Phys. D: Appl. Phys., 19; May 1986, pp. L147-L151.
Robert Turner, Minimum Inductance Coils, J. Phys.
Ed. Sci., 21 (5/1988), pp. 948-952. r
Primary Examiner—Kenneth Wieder
Assistant Examiner—W. S. Edmonds
Attorney, Agent, or Firm—Richard V. Westerhoff
Pickup coils for imaging magnetometers are formed from plural turns of a conductor with varying spacing between turns selected so that the Fourier transform of the coil turns function which is the filter function of the coil, has no zeroes within the spatial frequency bandwidth of the magnetic field generated by a two or three dimensional current to be imaged. Various exemplary coil configurations are presented including a Gaussian distribution for the turns of a planar coil.
26 Claims, 16 Drawing Sheets