The microwave calibration target’s surface temperature is simulated using the computational fluid dynamics simulation technologies

which overcomes the difficulties of traditional methods in measuring the small wedge of calibration targets at a high precision. An evaluation method to calculate the calibration target’s equivalent output temperature is introduced and the ref- erence depth value of embedding the temperature sensor is applied

which efficiently reduces the difference between the sensor’s measurement value and the calibration target’s equivalent output temperature. The uncertainty of the calibration target’s bright- ness temperature can be reduced within 0.5 K

which highly increases the measurement evaluation precision of the radiometer’s calibration system.