DocumentCode :
1290750
Title :
Analysis of focusing of pulsed baseband signals inside a layered tissue medium
Author :
Nikita, Konstantina S. ; Mitsis, Georgios D. ; Uzunoglu, Nikolaos K.
Author_Institution :
Dept. of Electr. & Comput. Eng., Nat. Tech. Univ. of Athens, Greece
Volume :
48
Issue :
1
fYear :
2000
fDate :
1/1/2000 12:00:00 AM
Firstpage :
30
Lastpage :
39
Abstract :
The derivation and application of a method designed to investigate the focusing properties of pulsed baseband signals of short pulsewidth (~1 ns) in biological tissue media are reported. To this end, sources fed from TEM waveguides, concentrically placed at the periphery of a three-layer cylindrical lossy model, are assumed. A Fourier-series-based methodology, appropriate for a useful class of pulse train incident signals, is presented and utilized to study the dynamics of pulse propagation inside the tissue medium. The propagation of each spectral component of the incident field within the tissue medium is analyzed by applying an integral-equation technique and a Fourier-series representation is used in order to obtain the time dependence of the electromagnetic fields produced at any point within tissue due to the pulsed excitation of the array elements. Numerical results are computed and presented at several points in a three-layer geometry, 20 cm in diameter, irradiated by an eight-element waveguide array. Focusing at a specific point of interest within tissue is achieved by properly adjusting the time delay of the signals injected to the individual applicators of the array
Keywords :
Fourier series; biological effects of microwaves; electromagnetic fields; focusing; hyperthermia; integral equations; 20 cm; Fourier-series-based methodology; TEM waveguides; array elements; biological tissue media; eight-element waveguide array; electromagnetic fields; focusing; integral-equation technique; layered tissue medium; pulse propagation; pulse train incident signals; pulsed baseband signals; spectral component; three-layer cylindrical lossy model; three-layer geometry; time delay; Baseband; Biological system modeling; Biological tissues; Design methodology; Electromagnetic analysis; Electromagnetic propagation; Electromagnetic waveguides; Signal analysis; Signal design; Space vector pulse width modulation;
fLanguage :
English
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9480
Type :
jour
DOI :
10.1109/22.817469
Filename :
817469
Link To Document :
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