Journal article
Characterization of Implantable Antennas for Intracranial Pressure Monitoring: Reflection by and Transmission Through a Scalp Phantom
IEEE transactions on microwave theory and techniques, v 56(10), pp 2366-2376
01 Oct 2008
Featured in Collection : UN Sustainable Development Goals @ Drexel
Abstract
Characterization of implantable planar inverted-F antennas, designed for intracranial pressure (ICP) monitoring at 2.45 GHz, is presented. A setup, incorporating a scalp phantom emulating the implant environment and an absorbing chamber, was implemented for characterizing the antennas, in terms of their reflection coefficient (S-11), resonance frequency (f(r)), and transmission coefficient through the phantom (S-21), and is re- ported for the first time. As a result of our observations that even a very slight change of the biocompatible (silicone) thickness can drastically change the characteristics of such antennas, several antenna prototypes with various silicone thicknesses were tested for a better understanding of the change in their performance with thickness. The main contributions of this paper rest in the evaluation of the antenna characteristics with respect to time, temperature, and far-field radiation, in an emulated biological environment. In this regard, the impact of the coating thickness on fr, drift of fr, S-11, and S-21 over time, and the effective radiated power (ERP) from the transmission (S-21) measurements were evaluated through careful measurements. A decrease in S, 1 of 1.2-2.3 dB and an increase in S-21 of 2.2-2.4 dB, over a period of two days, were observed at 2.45 GHz. A decrease of 8-18 MHz for f(r), was also observed over the same period of time. This drift was due to the absorption of saline by the silicone, leading to a change in its effective dielectric property. An f, increase of approximately 14.5 MHz was also observed by raising the temperature from 20 degrees C to 37 degrees C, mainly because of the negative temperature coefficient of the phantom permittivity. Transmission measurements performed using both S-21 and the received power measurement (for an ICP device mimic) yielded a maximum ERP of approximately 2 mW per. 1 W of power delivered to the antennas at 2.45 GHz.
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Details
- Title
- Characterization of Implantable Antennas for Intracranial Pressure Monitoring: Reflection by and Transmission Through a Scalp Phantom
- Creators
- Ruchi Warty - Jensen HughesMohammad-Reza Tofighi - Pennsylvania State UniversityUsmah Kawoos - Drexel UniversityArye Rosen - Drexel University
- Publication Details
- IEEE transactions on microwave theory and techniques, v 56(10), pp 2366-2376
- Publisher
- IEEE
- Number of pages
- 11
- Grant note
- Microwave-Photonics Device Laboratory Lightwave Engineering Laboratory Drexel University
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Electrical and Computer Engineering
- Web of Science ID
- WOS:000260093400023
- Scopus ID
- 2-s2.0-54049113366
- Other Identifier
- 991022065614404721
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- Collaboration types
- Domestic collaboration
- Web of Science research areas
- Engineering, Electrical & Electronic