Abstract
For the last four years the Laboratory of Biometrology of PUC-Rio has been working in the development of magnetic field transducers to be used in biomedical applications — especially in the three-dimensional localization of needles inserted in the human body and in the measurment of arterial pulse waves. While previous investigations were based on the behavior of the magnitude of the impedance of Giant Magnetoimpedance (GMI) ribbon-shaped sensors, this manuscript presents the preliminary results of a new research that considers the changes in the phase characteristics of GMI sensors due to varying low-intensity magnetic fields. In spite of being less explored in the literature, the work carried out so far indicates that the sensitivity of the phase can lead to more promising results than the ones already obtained with transducers based on the variation of the impedance magnitude. By means of examples showing that the sensitivity of the phase is affected by parameters (amplitude, frequency and DC level) of the AC biasing current that flows throught the sensor, this manuscript discusses how an ideal stimulation condition was derived in order to obtain more sensitive transducers. It is also examined the influence of the ribbon length in the sensitivity. A new conditioning electronic circuit — responsible for the excitation and measurement of the GMI sensor, and designed to work in the 100kHz to 5Mhz range — has been developed and is presented in the manuscript. Simulation studies of the complete transducer, including the conditioning circuit and based on data obtained from measured curves, have shown that an improvement of 10 to 100 times can be expected when compared to the sensitivity of previous magnitude-based transducers.
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References
Pompéia F, Gusmão L A P, Hall Barbosa C R, Costa Monteiro E, Gonçalves L A P, Machado F L A (2008) Ring shaped magnetic field transducer based on the GMI effect. Meas. Sci. Technol. at http://www.iop.org/EJ/abstract/0957-0233/19/2/025801/ DOI 10.1088 /0957-0233/19/2/025801
Ramos Louzada D, Costa Monteiro E, Gusmão L A P, Hall Barbosa C R (2007) “Medição não-invasiva de ondas de pulso arterial utilizando transdutor de pressão MIG” Proceedings do IV Latin American Congress on Biomedical Engineering, Brazil
Fert A (2007) The origin, development and future of spintronics. Nobel Lecture, Stockholm, Sweden, 2007 at http://nobelprize.org /nobel_prizes/physics/laureates/2007/fert_lecture_OnlinePDF.pdf
Grünberg P (2007) From spinwaves to giant magneto magnetoresistence (GMR) and beyond. Nobel Lecture, Stockholm, Sweden, 2007 at http://nobelprize.org/nobel_prizes/physics/laureates/2007/grunberg_lecture_OnlinePDF.pdf
Machado F L A and Rezende S M (1996) A theoretical model for the giant magnetoimpedance in ribbons of amorphous soft-ferromagnetic alloys. J. Appl. Phis. 79:6958–6960 DOI 10.1063/1.361945
Knobel V and Pirota K R (2002) Giant magnetoimpedance concepts and recent progress. J. Magn. Magn. Mater. 242–245:33–40 DOI 10.1016/S0304-8853(01)01180-5
Costa Monteiro E, Hall Barbosa C R, Andrade Lima E, Costa Ribeiro P, Boechat P (2000) Locating steel needles in the human body using a SQUID magnetometer. Phys. Med. Biol. 45:2389–2402 DOI 10.1088/0031-9155/45/8/323
Hall Barbosa C, Costa Monteiro E and Pompéia F (2003) Localization of magnetic foreign bodies in human using magnetic field sensors. 17th IMEKO World Congress, Dubrovnik, Croatia, 2003, pp 22–27
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© 2009 International Federation of Medical and Biological Engineering
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Silva, E.C., Gusmão, L.A.P., Barbosa, C.R.H., Monteiro, E.C. (2009). Magnetic field transducers based on the phase characteristics of GMI sensors and aimed at biomedical applications. In: Lim, C.T., Goh, J.C.H. (eds) 13th International Conference on Biomedical Engineering. IFMBE Proceedings, vol 23. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-92841-6_160
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DOI: https://doi.org/10.1007/978-3-540-92841-6_160
Publisher Name: Springer, Berlin, Heidelberg
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