Actually, in a domestic microwave oven, the food products cannot
fully absorb the input power of the microwave during heating,
as the impedance mismatch of the load leads to the reflection of
some energy back to the magnetron, which means that the power
absorbed by the load will not be equal to the original rated power
(Pitchai et al., 2012). The real microwave power absorbed by food
products in the experiment could be measured by the IEC or IMPI
method (Buffler, 1992; IEC, 1988; IMPI, 1989).