JEMAA  Vol.4 No.9 , September 2012
An Over-Moded TEM Cell System for in vivo Exposure at 2.45 GHz
Abstract: A TEM cell designed to operate at 900 MHz for exposing small-restrained animals (e.g. mice) has been theoretically, numerically and experimentally characterized at 2.45 GHz, which is the central frequency of the WiFi protocol. This study aims at evaluating the influence of higher order modes on the field homogeneity. The results demonstrate the superimposition of a tolerable standing wave, due to reflections at the cell terminations, and a slight beat wave due to the interference between different modes. Nevertheless, the final outcome is that the system can still be efficiently used to expose small animals in specific WiFi channels, provided they are properly placed in correspondence to the maxima of the electric field along the guide length.
Cite this paper: A. Paffi, C. Merla, M. Liberti, F. Fratta, R. Pinto, G. Lovisolo and F. Apollonio, "An Over-Moded TEM Cell System for in vivo Exposure at 2.45 GHz," Journal of Electromagnetic Analysis and Applications, Vol. 4 No. 9, 2012, pp. 345-352. doi: 10.4236/jemaa.2012.49048.

[1]   J. Juutilainen, A. Hoyto, T. Kumlin and J. Naarala, “Re- view of Possibile Modulated-Dependent Biological Ef- fects of RF Fields,” Bioelectromagnetics, Vol. 32, No. 7, 2011, pp. 511-534. doi:10.1002/bem.20652

[2]   L. Verschaeve, J. Juutilainen, I. Lagroye, J. Miyakoshi, R. Saunders, R. de Seze, T. Tendford, E. van Rongen, B. Veyret and Z. Xu, “In Vitro and in Vivo Genotoxicity of Radiofrequency Fields,” Mutagenesis Research, Vol. 705, No. 3, 2010, pp. 252-268.

[3]   N. Desai, K. K. Kesari and A. Agarwal, “Pathophysi- ology of Cell Phone Radiation: Oxidative Stress and Car- cinogenesis with Focus on Male Reproductive System,” Reproductive Biology and Endocrinology, Vol. 7, 2009, 114.

[4]   A. Paffi, F. Apollonio, G. A. Lovisolo, C. Marino and M. Liberti, “Exposure Systems for Bioelectromagnetic In- vestigations in the Radiofrequency Range: Classification and Emerging Trends,” Proceedings of the 5th European Conference on Antennas and Propagation, Rome, 2011, pp. 3159-3163.

[5]   T. Samaras, N. Kuster and S. Negovetic, “Scientific Re- port: Workshop on EMF Health Risk Research Lessons Learned and Recommendation for the Future,” Centro Stefano Franscini, Monte Verità Switzerland, Deliver- ables D36-D37, EMF-NET Project, 2005.

[6]   M. L. Crawford, “Generation of Standard EM Field Using TEM Transmission Cells,” IEEE Transactions on Elec- tromagnetic Compatibility, Vol. EMC-16, No. 4, 1974, pp. 189-195. doi:10.1109/TEMC.1974.303364

[7]   L. Ardoino, V. Lopresto, S. Mancini, C. Marino, R. Pinto and G. A. Lovisolo, “A Radio-Frequency System for in Vivo Pilot Experiments Aimed at the Studies on Bio- logical Effects of Electromagnetic Fields,” Physics in Medicine and Biology, Vol. 50, No. 15, 2005, pp. 3643- 3654. doi:10.1088/0031-9155/50/15/011

[8]   Wireless LAN Medium Access Control (MAC) and Physi- cal Layer (PHY) Specification, “Higher-Speed Physical Layer Extension to 54 Mbps,” 2003.

[9]   Q. Balzano, C. Chou, R. Cicchetti, A. Faraone and R. Y. Tay, “An Efficient RF Exposure System with Precise Whole-Body Average SAR Determination for in Vivo Animal Studies at 900 MHz,” IEEE Transactions on Mi- crowave Theory and Techniques, Vol. 48, No. 11, 2000, pp. 2040-2049. doi:10.1109/22.884193

[10]   T. Wu, A. Hadjem, M. Wong, A. Gati, O. Picon and J. Wiart, “Whole-Body New-Born and Young Rats’ Ex- posure Assessment in a Reverberating Chamber Operat- ing at 2.45 GHz,” Physics in Medicine and Biology, Vol. 55, No. 6, 2010, pp. 1619-1630. doi:10.1088/0031-9155/55/6/006

[11]   R. Pinto, V. Lopresto, P. Galloni, C. Marino, S. Mancini, R. Lodato, C. Pioli and G. A. Lovisolo, “Dosimetry of a Set- Up for the Exposure of Newborn Mice to 2.45 GHz WiFi Frequencies,” Radiation Protection Dosimetry, Vol. 140, No. 4, 2010, pp. 326-332. doi:10.1093/rpd/ncq129

[12]   A. Paffi, C. Merla, M. Liberti, F. Fratta, R. Pinto, G. A. Lovisolo and F. Apollonio, “A TEM Cell System for in Vivo Exposure at 2.45 GHz,” Proceedings of the 6th Euro- pean Conference on Antenna and Propagation, Prague, 26- 30 March 2012, pp. 1099-1101.

[13]   L. Gruner, “Higher-Order Modes in Rectangular Coaxial Waveguides,” IEEE Transactions on Microwave Theory and Techniques, Vol. 15, No. 8, 1967, pp. 483-485. doi:10.1109/TMTT.1967.1126510

[14]   M. T. Ma, M. Kanda, M. L. Crawford and E. B. Larsen, “A Review of Electromagnetic Compatibility/Interference Measurement Methodologies,” Proceedings of IEEE, Vol. 73, No. 3, 1985, pp. 388-411. doi:10.1109/PROC.1985.13164

[15]   Z. Chen, “Examinations of Higher Order Mode Cut-Off Frequencies in Symmetrical TEM Cells,” Proceedings of IEEE International Symposium on Electromagnetic Com- patibility, Austin, 17-21 August 2009, pp.6-11. doi:10.1109/ISEMC.2009.5284659

[16]   C. Groh and J. P. Kaerst, “Analytical Calculation of Resonances in Tapered Double-Port TEM Waveguides,” IEEE Transactions on Electromagnetic Compatibility, Vol. 48, No. 2, 2006, pp. 431-435. doi:10.1109/TEMC.2006.874083

[17]   P. Wilson and M. T. Ma, “Simple Approximate Expres- sions for Higher Order Mode Cut-Off and Resonant Fre- quencies in TEM Cells,” IEEE Transactions on Electro- magnetic Compatibility, Vol. 28, No. 3, 1986, pp. 125- 130. doi:10.1109/TEMC.1986.4307269

[18]   D. Roddy, “Microwave Technology,” Prentice-Hall, Engle- wood Cliffs, 1986.

[19]   P. F. Biagi, L. Castellana, T. Maggipinto, G. Maggipinto, T. Ligonzo, L. Schiavulli and D. Loiacono, “A Rever- beration Chamber to Investigate the Possible Effects on ‘in Vivo’ Exposure of Rats to 1.8 GHz Electromagnetic Fields: A Preliminary Study,” Progress in Electromag- netic Research, Vol. 94, 2009, pp. 133-152. doi:10.2528/PIER09061006