Evaluation of a semi-cylindrical solenoid as an applicator for radio-frequency hyperthermia.

A modified solenoid having a semi-circular cross section is evaluated as an applicator for radio-frequency heating of biological materials. The operating efficiency of this applicator and the distribution of the electric field established within a simulated biological sample are determined for a number of modes of excitation. It is shown that uniform heating to a substantial depth is possible at efficiencies in excess of 80 percent.

Simple cell for the measurement of the radio frequency electrical properties of earth materials.

The design of a simple cell for determining the radio frequency electrical properties of earth materials is described. Basically, the cell consists of a coaxial sample holder fitted with electric and magnetic field probes. When excited as a section of transmission line the induced probe voltages are related in a straightforward manner to the electrical properties of the sample. The device is intended for use with a vector voltmeter which permits the direct and simultaneous measurement of the relative amplitudes and phases of these probe voltages. The cell permits the accurate and rapid determination of the conductivity and dielectric constant of earth materials over the frequency range 1 MHz-1 GHz, without the tedious and time consuming procedures associated with the bridge and slotted line techniques commonly used in this frequency range.