A Liquid with Tuneable Dielectric Properties for Wideband Microwave Sensing of Biological Targets

摘要

Biomedical microwave systems require antenna-to-body matching to transfer electromagnetic energy efficiently through the skin and inside the body. In this paper a paraffin oil and saline water based matching liquid is presented that can be modified in a straight-forward manner to match various dielectrics. The permittivity of this liquid may be varied between 10-52 by altering the proportions of paraffin oil to water. The conductivity can be varied between 0.3 and l.0S/m (at 3GHz) by altering the salinity of the water, without significantly altering the permittivity. Dielectric measurements and one- and two-pole Debye parameters are given for a range of different mixtures at frequencies of 0.5-10GHz. The results highlight the flexibility of the matching liquid and mark it as a suitable antenna coupling medium as well as a biological phantom material in the low GHz range.