Complex Permittivity Measurement of Artificial Tissue Emulating Material Using Open-Ended Coaxial Probe

In this paper, we present a complex permittivity measurement technique for artificial tissue emulating (ATE) materials. Recently, ATE materials have gained increasing attention due to their importance on the in-vitro testing for implantable biomedical devices. They are in semi-solid state and have frequency dependent dielectric properties, thus a broadband characterization technique is called for to measure their permittivity. The target frequency range of the proposed broadband technique is 0.5 - 6 GHz and is based on an open-ended coaxial probe (OECP). Different from the commercial OECP techniques, the in-house built OECP system employs simpler calibration steps which eliminate the need of short-standard measurement often producing errors. The equivalent circuit analysis shows that the short-standard measurement can be substituted by the open-standard measurement with the opposite polarity. The validity of the proposed technique was demonstrated by measuring the complex permittivity of ATE materials for brain in-vitro testing.