DocumentCode :
863494
Title :
Experimental and numerical investigation of feed-point parameters in a 3-D hyperthermia applicator using different FDTD models of feed networks
Author :
Nadobny, Jacek ; Fähling, Horst ; Hagmann, Mark J. ; Turner, Paul F. ; Wlodarczyk, Waldemar ; Gellermann, Johanna M. ; Deuflhard, Peter ; Wust, Peter
Author_Institution :
Klinik fur Strahlenheilkunde, Charite-Campus Virchow Klinikum, Berlin, Germany
Volume :
49
Issue :
11
fYear :
2002
Firstpage :
1348
Lastpage :
1359
Abstract :
Experimental and numerical methods were used to determine the coupling of energy in a multichannel three-dimensional hyperthermia applicator (SIGMA-Eye), consisting of 12 short dipole antenna pairs with stubs for impedance matching. The relationship between the amplitudes and phases of the forward waves from the amplifiers, to the resulting amplitudes and phases at the antenna feed-points was determined in terms of interaction matrices. Three measuring methods were used: (1) a differential probe soldered directly at the antenna feed-points; (2) an E-field sensor placed near the feed-points; and (3) measurements were made at the outputs of the amplifier. The measured data were compared with finite-difference time-domain (FDTD) calculations made with three different models. The first model assumes that single antennas are fed independently. The second model simulates antenna pairs connected to the transmission lines. The measured data correlate best with the latter FDTD model, resulting in an improvement of more than 20% and 20° (average difference in amplitudes and phases) when compared with the two simpler FDTD models.
Keywords :
antenna phased arrays; biomedical equipment; finite difference time-domain analysis; hyperthermia; impedance matching; modelling; radiation therapy; radiofrequency heating; E-field sensor; amplifier outputs; antenna feed-points; antenna phased array; differential probe; differential probe measurements; experimental methods; feed networks; forward waves; impedance matching networks; interaction matrices; measuring methods; numerical methods; single antennas; therapeutic RF heating; transmission lines; Antenna feeds; Antenna measurements; Applicators; Dipole antennas; Finite difference methods; Hyperthermia; Impedance matching; Time domain analysis; Transmission line matrix methods; Transmission line measurements; Computer Simulation; Electric Impedance; Electromagnetic Fields; Equipment Design; Finite Element Analysis; Heat; Humans; Hyperthermia, Induced; Models, Biological; Neoplasms; Radio Waves; Sensitivity and Specificity;
fLanguage :
English
Journal_Title :
Biomedical Engineering, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9294
Type :
jour
DOI :
10.1109/TBME.2002.804585
Filename :
1046943
Link To Document :
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