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The Scientific World Journal
Volume 2014, Article ID 692434, 11 pages
Research Article

Study of the Effect of Distance and Misalignment between Magnetically Coupled Coils for Wireless Power Transfer in Intraocular Pressure Measurement

1Graduate Department, National Polytechnic Institute of Mexico (IPN), ESIME UPC, Avenida Santa Ana 1000, San Francisco Culhuacan, 04260 Mexico City, DF, Mexico
2Electronics Department, INAOE, Luis Erro 1, 72840 Santa Maria Tonantzintla, PUE, Mexico
3APEC, The Association to Avoid Blindness in Mexico, Hospital Luis Sanchez Bulnes, Vicente Garcia Torres 46, 04030 Coyoacan, DF, Mexico

Received 23 April 2014; Accepted 9 June 2014; Published 6 July 2014

Academic Editor: Antonio García-Zambrana

Copyright © 2014 Adrian E. Rendon-Nava et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


An analysis of the effect of distance and alignment between two magnetically coupled coils for wireless power transfer in intraocular pressure measurement is presented. For measurement purposes, a system was fabricated consisting of an external device, which is a Maxwell-Wien bridge circuit variation, in charge of transferring energy to a biomedical implant and reading data from it. The biomedical implant is an RLC tank circuit, encapsulated by a polyimide coating. Power transfer was done by magnetic induction coupling method, by placing one of the inductors of the Maxwell-Wien bridge circuit and the inductor of the implant in close proximity. The Maxwell-Wien bridge circuit was biased with a 10 MHz sinusoidal signal. The analysis presented in this paper proves that wireless transmission of power for intraocular pressure measurement is feasible with the measurement system proposed. In order to have a proper inductive coupling link, special care must be taken when placing the two coils in proximity to avoid misalignment between them.