A Microwave Compatible MIC Temperature Electrode for Use in Biological Dielectrics

A microwave compatible four-terminal electrode design based on hybrid microwave integrated circuit (MIC) construction is presented. The concept of electrothermal matching is employed to prevent artifact in either of two directions: heat sourcing and heat sinking. The electrode system includes a temperature-encoding electronic package. The electrode is designed for use in the brain at a specific insertion depth. It has been tested by thermographic methods for electromagnetic properties at 2450 MHz and a power density of ~250 mW/cm². The system has been thermometrically evaluated for calibration stability and freedom from hysteresis. Stability and artifact has been shown to be within ±15°C independent of temperature cycling and/or thermal history.