Field and Temperature Gradients from Short Conductors in a Dissipative Medium
This paper considers the specific absorption rate (SAR) in tissue of radiofrequency (RF) energy and temperature increases produced by RF currents on short conductors (0.03–0.1λ). We consider a cylindrical model in which a center-feeds, insulated antenna is embedded in tissue. We introduce...
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| Format: | Article |
| Language: | English |
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Wiley
2007-01-01
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| Series: | International Journal of Antennas and Propagation |
| Online Access: | http://dx.doi.org/10.1155/2007/57670 |
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| author | Quirino Balzano Kenneth R. Foster Asher R. Sheppard |
| author_facet | Quirino Balzano Kenneth R. Foster Asher R. Sheppard |
| author_sort | Quirino Balzano |
| collection | DOAJ |
| description | This paper considers the specific absorption rate (SAR) in tissue of radiofrequency (RF) energy and temperature increases produced by RF currents on short conductors
(0.03–0.1λ). We consider a cylindrical
model in which a center-feeds, insulated antenna is embedded in tissue. We introduce a new method for
the analytic evaluation of the fields in the cylindrical phantom taking advantage of the axial symmetry of the
antenna and the tissue. Results of the analytical model are compared to results of numerical
(finite difference time domain) simulations; in addition, the thermal response of the exposed material is
calculated by finite element
solution of the heat
conduction equation. For model
antennas of 1 to 3 cm total length with a feedpoint current of 10mA RMS at 900MHz, the maximum SAR
(in tissue next to the antenna) is less than ∼2.5W/kg. SAR decays rapidly with radial distance from the antenna (∼r−4 for the 1cm antenna) and creates a steady-state temperature rise less than 0.05K at the location of SARmax. Heat conduction causes the temperature to decline steeply with radius (depth into tissue). |
| format | Article |
| id | doaj-art-17ecf7f081b54dac8860176cb8281bf4 |
| institution | OA Journals |
| issn | 1687-5869 1687-5877 |
| language | English |
| publishDate | 2007-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | International Journal of Antennas and Propagation |
| spelling | doaj-art-17ecf7f081b54dac8860176cb8281bf42025-08-20T02:02:26ZengWileyInternational Journal of Antennas and Propagation1687-58691687-58772007-01-01200710.1155/2007/5767057670Field and Temperature Gradients from Short Conductors in a Dissipative MediumQuirino Balzano0Kenneth R. Foster1Asher R. Sheppard2Department of Electrical and Computer Engineering, University of Maryland, College Park, MD 20742, USADepartment of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, 210 S. 33rd Street, Philadelphia, PA 19104-6392, USAAsher Sheppard Consulting, 108 Orange Street, Suite 8, Redlands, CA 92373, USAThis paper considers the specific absorption rate (SAR) in tissue of radiofrequency (RF) energy and temperature increases produced by RF currents on short conductors (0.03–0.1λ). We consider a cylindrical model in which a center-feeds, insulated antenna is embedded in tissue. We introduce a new method for the analytic evaluation of the fields in the cylindrical phantom taking advantage of the axial symmetry of the antenna and the tissue. Results of the analytical model are compared to results of numerical (finite difference time domain) simulations; in addition, the thermal response of the exposed material is calculated by finite element solution of the heat conduction equation. For model antennas of 1 to 3 cm total length with a feedpoint current of 10mA RMS at 900MHz, the maximum SAR (in tissue next to the antenna) is less than ∼2.5W/kg. SAR decays rapidly with radial distance from the antenna (∼r−4 for the 1cm antenna) and creates a steady-state temperature rise less than 0.05K at the location of SARmax. Heat conduction causes the temperature to decline steeply with radius (depth into tissue).http://dx.doi.org/10.1155/2007/57670 |
| spellingShingle | Quirino Balzano Kenneth R. Foster Asher R. Sheppard Field and Temperature Gradients from Short Conductors in a Dissipative Medium International Journal of Antennas and Propagation |
| title | Field and Temperature Gradients from Short Conductors in a Dissipative Medium |
| title_full | Field and Temperature Gradients from Short Conductors in a Dissipative Medium |
| title_fullStr | Field and Temperature Gradients from Short Conductors in a Dissipative Medium |
| title_full_unstemmed | Field and Temperature Gradients from Short Conductors in a Dissipative Medium |
| title_short | Field and Temperature Gradients from Short Conductors in a Dissipative Medium |
| title_sort | field and temperature gradients from short conductors in a dissipative medium |
| url | http://dx.doi.org/10.1155/2007/57670 |
| work_keys_str_mv | AT quirinobalzano fieldandtemperaturegradientsfromshortconductorsinadissipativemedium AT kennethrfoster fieldandtemperaturegradientsfromshortconductorsinadissipativemedium AT asherrsheppard fieldandtemperaturegradientsfromshortconductorsinadissipativemedium |