Inductance Calculations of Variable Pitch Helical Inductors

Report No. ARL-TR-7380
Authors: Peter T Bartkowski; Paul R Berning
Date/Pages: August 2015; 32 pages
Abstract: A technique has been developed to calculate the inductance of variable pitch helicoil inductors of rectangular cross section that use a coaxial return feed along the center of the coil. The calculations discretize the coil into a series of rings of current that take into account the diffusion of current or skin depth. The inductance is a combination of each rings self-inductance and the mutual inductances of all the current rings. To validate the technique, a series of coils were machined from aluminum tubes and then their inductances were measured at 3 different frequencies. The calculated inductances are compared to the measured inductances.
Distribution: Approved for public release
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Last Update / Reviewed: August 1, 2015