Meaning
Chemical mixtures that simulate the electromagnetic absorption characteristics of human tissue are used to fill the test containers during wireless compliance testing. The phantom tissue liquid must match the permittivity and conductivity of the human body at the specific test frequency. This match ensures that the measured energy absorption replicates the actual exposure of a user.
Dielectric Mixture
Liquid formulations use water, salt, sugar and other organic compounds to achieve the target electrical properties. The ratio of these ingredients is adjusted depending on the frequency band being evaluated. This mixture must be stirred thoroughly to ensure a homogeneous distribution of the components before the test starts.
Temperature Limit
Temperature ranges must be kept constant during the measurement sequence to prevent changes in the dielectric properties. A typical range is between twenty and twenty-four degrees Celsius, which is monitored with a calibrated thermometer. If the temperature fluctuates beyond this range, the measurements must be paused until the liquid is stabilized.
Calibration Schedule
Electrical measurement of the mixture is completed before each test run using a coaxial probe and a network analyzer. Over time, evaporation of the water content can alter the dielectric parameters, requiring the liquid to be replaced or corrected. This routine verification is documented in the test report to demonstrate that the test setup complied with international standards throughout the evaluation process.
