A Comparison of Electrically Short Bare and Insulated Probes for Measuring the Local Radio Frequency Electric Field in Biological Systems

The problems associated with measuring the local electric field in a medium with spatally inhomogeneous electrical constitutive parameters like biological tissue are discussed. Simple theoretical analyses that describe the operation of electrically short bare and insulated electric field probes in a dissipative medium are presented. The conditions that must be satisfied for each of these probes to have an electric field response that is independent of the electrical constitutive parameters of the surrounding tissue are determined. The results of a systematic experimental study of both types of probes are presented. In the study the probes were immersed in a succession of liquids with dielectric properties similar to those for biological tissues at radio frequencies.

[1]  R. King,et al.  Insulated linear antenna: Theory and experiment. II , 1974 .

[2]  Edward E. Aslan,et al.  Electromagnetic Radiation Survey Meter , 1970 .

[3]  Kam Li,et al.  Capacity and Conductivity of Body Tissues at Ultrahigh Frequencies , 1953, Proceedings of the IRE.

[4]  H P Schwan,et al.  Microwave radiation: biophysical considerations and standards criteria. , 1972, IEEE transactions on bio-medical engineering.

[5]  H P Schwan,et al.  Hot spots generated in conducting spheres by electromagnetic waves and biological implications. , 1972, IEEE transactions on bio-medical engineering.

[6]  Dispersion and Absorption in Dielectrics 1 , 2022 .

[7]  A. Guy,et al.  Nonionizing electromagnetic wave effects in biological materials and systems , 1972 .

[8]  A. Rudge.  An Electromagnetic Radiation Probe for Near-Field Measurements at Microwave Frequencies* , 1970 .

[9]  Measurement techniques for antennas in dissipative media , 1973 .

[10]  A. W. Guy,et al.  Analyses of Electromagnetic Fields Induced in Biological Tissues by Thermographic Studies on Equivalent Phantom Models , 1971 .

[11]  R. Spiegel,et al.  Resonance Absorption of Microwaves by the Human Skull , 1974 .

[12]  R. R. Bowman,et al.  Quantifying Hazardous Electromagnetic Fields: Scientific Basis and Practical Considerations , 1971 .

[13]  G. Sinclair.  Theory of Models of Electromagnetic Systems , 1948, Proceedings of the IRE.

[14]  K. Cole,et al.  Dispersion and Absorption in Dielectrics I. Alternating Current Characteristics , 1941 .

[15]  H. P. Schwan,et al.  Interaction of Microwave and Radio Frequency Radiation with Biological Systems , 1971 .