Specific absorption rates were measured in three locations of humans exposed in the far field at 160, 350, and 915 MHz. Values obtained for six males are compared with data for a full-scale homogeneous model of man.

The electric field strength was measured in a full-scale heterogeneous model of man exposed in the near field of resonant dipoles. The model was comprised of skull, spinal cord, rib cage, all other major bones, brain, lung, and muscle tissue. Electrical properties of these simulated tissues were the same as respective live tissue properties at test frequencies of 160, 350, and 915 MHz. The rates of energy absorption were calculated on the basis of the measured field strengths and tissue conductivities. Patterns of the energy deposition are compared for two orientations of the antennas with respect to the body. Also the results for the heterogeneous model are compared to data for homogeneous model having average tissue electrical properties.

The specific absorption rate (SAR) was measured in over 650 locations in a full-scale model of man exposed in the far and near field of antennas at 350 and 915 MHz. The whole-body average, the body-parts average, and the distributions of the SAR's are compared for three wave polarizations for the far and the near-field exposures. Effects on the energy deposition of the antenna type, gain, and location in the near field are discussed.

The spatial distribution of the specific absorption rate (SAR) was measured in a full-scale model of man using implantable electric field probes. The model was exposed in the near-field of linear and aperture antennas at 350 MHz. Effects of the wave polarization, antenna position and antenna gain on the SAR distribution and the average SAR in the whole-body and body parts are reported.

Dielectric properties of raw, unprocessed potatoes, carrots, apples, peaches and pears were measured at room temperature in the frequency range from 100 to 10000 MHz. Experimental methods and the sample holder are briefly described. The results for the dielectric constant and the loss factor are presented as a function of frequency. The results are in good agreement with theoretical data obtained from Maxwell's mixture theory.

An open-ended coaxial line and a computer-controlled network analyzer have been extensively used for measuring the tissue permittivity in vivo at radio and microwave frequencies. An analysis is presented of measurement errors resulting from calibration and random errors of the network analyzer [1],[2]. The uncertainties in our system are ΔΓ = 0.05 dB and Δϕ = 0.3°. Key Words-Radio frequency, Micro...

Routine network analyzer calibration procedures in measurements of the dielectric properties of materials using an open-ended coaxial line probe are frequently inadequate and limit the accuracy of measurements. A calibration method, which makes use of liquids whose properties are well known, is proposed to alleviate this limitation. It is shown that even one liquid used as a standard in place of a matched load greatly improves the accuracy of measurements. Theoretical relationships and experimental results as well as some practical suggestions related to the application of this method are given.

Capacitance of open-ended coaxial lines is determined experimentally using a resonant technique. An empirical expression for the capacitance versus frequency, which enables the open circuit to be used as a calibration standard for microwave network analyzers, is proposed and verified.

An open-ended coaxial line and an improved measurement method employing a computer controlled network analyzer were used to measure the permittivity of cat tissues. Muscle, spleen, kidney cortex, liver,and brain cortex were measured in vivo and in vitro at frequencies between 100 MHz and 8 GHz. The differences between the permittivities of these cat tissues, in the aforementioned range of frequencies, when measured in vivo and a few (up to four) hours after death, were found to be within the experimental uncertainty.