Measuring the dielectric properties of 0.1M sodium chloride using a waveguide technique at X - band

Abstract

In recent years, an interest arose on hyperthermia treatment of human tissue by administering microwave radiation to kill tumour cells (cell necrosis). This requires a good understanding of complex permittivity of human tissues for accurate determination of the absorbed power. One such example is the bone tissue. As yet, there is limited knowledge on the dielectric properties of bone and hence one needs more complex permittivity measurements for better understanding. Measurements for complex permittivity of bone found on several papers use the open ended probe technique. This technique has limitations on solids due to air gaps that may be present; not visible to the naked eye. This leads to the idea of measuring the dielectric properties of bone using the waveguide technique. In this study, attempts to measure the complex permittivity of 0.1 M Sodium Chloride are investigated in order to validate future measurements on dielectric properties of bone using waveguide technique, owing to the similarity in the dielectric properties between the two. Measurements are done in the X - band microwave frequency range. Results of 0.1 M Sodium Chloride are validated by the use of standard materials given by the manufacturer of the waveguide for validation purposes. The dielectric properties of these standard materials are measured using both transmission and reflection measurements and using several conversion models. Measurements on 0.1 M Sodium Chloride follow, explaining in detail the procedure followed and limitations encountered using the open - ended waveguide technique. Finally, measurements are discussed and compared to published data.