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International Journal of Antennas and Propagation
Volume 2014 (2014), Article ID 749043, 9 pages
http://dx.doi.org/10.1155/2014/749043
Research Article

Design of a Small Modified Minkowski Fractal Antenna for Passive Deep Brain Stimulation Implants

Department of Electrical and Computer Engineering, Florida International University, Miami, FL 33174, USA

Received 23 June 2014; Revised 7 August 2014; Accepted 1 September 2014; Published 4 November 2014

Academic Editor: Rashidul Islam

Copyright © 2014 Sara Manafi and Hai Deng. 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.

Abstract

A small planar modified Minkowski fractal antenna is designed and simulated in dual frequency bands (2.4 and 5.8 GHz) for wireless energy harvesting by deep brain stimulation (DBS) devices. The designed antenna, physically being confined inside a miniaturized structure, can efficiently convert the wireless signals in dual ISM frequency bands to the energy source to recharge the DBS battery or power the pulse generator directly. The performance metrics such as the return loss, the specific absorption rate (SAR), and the radiation pattern within skin and muscle-fat-skin tissues are evaluated for the designed antenna. The gain of the proposed antenna is 3.2 dBi at 2.4 GHz and 4.7 dBi at 5.8 GHz; also the averaged SAR of the antenna in human body tissue is found to be well below the legally allowed limit at both frequency bands. The link budget shows the received power at the distance of 25 cm at 2.4 GHz and 5.8 GHz are around 0.4 mW and 0.04 mW, which can empower the DBS implant. The large operational bandwidth, the physical compactness, and the efficiency in wireless signal reception make this antenna suitable in being used in implanted biomedical devices such as DBS pulse generators.