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Multi‐turn, printed surface coil inductance, and Q optimization
Author(s) -
Raad Ahmad,
Kan Siew
Publication year - 1993
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1910290318
Subject(s) - inductance , electromagnetic coil , turn (biochemistry) , radius , surface (topology) , spiral (railway) , equivalent series inductance , materials science , physics , geometry , optics , nuclear magnetic resonance , electrical engineering , mathematics , mathematical analysis , computer science , engineering , computer security , voltage
Abstract Wheeler's empirical inductance formula for a multi‐turn, close‐wound flat coil shows that the maximum inductance for a given length of wire occurs when the outer to inner radius ratio is equal to 15/7. A similar expression is proposed for a flat, printed spiral for surface coil antenna design by modifying one of the coefficients in Wheeler's formula. Measured inductance is in good agreement with this new formula and the optimum radius ratio for maximum inductance or Q is now of the order of 9/5.