Meaning
Tissue-simulating liquids used in safety assessments represent the electromagnetic absorption characteristics of the human body. The phantom fluid is contained within a plastic shell that mimics the shape of a head or torso during SAR testing.
Chemical Composition
Specific formulations are used to achieve the desired dielectric properties for different tissue types. Mixing water, salt, and stabilizing chemicals allows phantom fluid to mimic either muscle or brain tissues. These ingredients must be balanced to cover the required frequency bands.
Calibration Protocol
Testing laboratories must verify the electrical parameters of the medium daily. Before any regulatory measurements, the phantom fluid is checked for permittivity and conductivity using a dedicated dielectric probe kit. If the properties fall outside the five percent tolerance, the fluid must be adjusted or replaced.
Measurement Reliability
Constant temperature control is necessary to prevent the electrical characteristics of the medium from drifting during the test. If the temperature of the phantom fluid varies by more than two degrees Celsius, the measurements become invalid. Robotic scanners move E-field probes through the liquid to collect accurate three-dimensional electric field data.
This automated scanning prevents the human error that occurs with manual measurements, ensuring the data is reliable and repeatable.
