2.2 Experimental Process
The microwave magnetrons were first powered on to start the heating of
the SiC bed, with four magnetrons of the ten started at each test. The
microwave leakage was detected to be less than 0.1
mW/cm2 in the area beyond the distance of 0.05 m from
the device, which meet the international safety standards [23]. The
real time temperature for the SiC bed surface (74,800 pixels points
totally) was recorded online by the infrared thermal imager. The
thermocouple located at the center of the bed surface was used for
temperature control. Microwave heating SiC bed was investigated in the
thermocouple controlling temperature range of 95-105 °C, 195-205 °C,
295-305 °C, 395-405 °C, and 495-505 °C respectively. Taking the
temperature range of 95-105 °C as an example, the microwave magnetrons
were powered on when the temperature detected by the thermocouple was
below 95 °C and powered off once the monitored temperature was above 105
°C. The measurement for each temperature range was carried out by
continuously repeating the cycle of temperature rise and drop for ten
times. For comparison purpose, the temperature and electric field
distributions of the SiC bed surface were simulated using a multiphysics
software. The details for the simulation can be found in our previous
report [11].