Electromagnetic heating of tissue-equivalent phantoms with thin, insulating partitions

The electromagnetic power absorption in tissue-equivalent phantoms that are used for evaluation of diathermy and hyperthermia applicators is analyzed for the purpose of determining the effect of an insulating partition that is frequently used to facilitate separation of the phantom for thermographic analysis of heating distributions. An analysis that is based on the plane wave spectrum decomposition of the electromagnetic field is applied to a simplified model of the medium. The simplified model is valid whenever the insulating partition does not significantly alter the fields in the medium. The curves that are presented indicate that thin partitions do not significantly alter the power absorption for most situations of therapeutic interest. Data on the effects of partition thickness and electrical parameters are presented for microwave and radiofrequencies of interest for diathermy and hyperthermia.