ABSTRACT
Objective: Nowadays, the power calibration methods of the microwave hyperthermia apparatus doesn't take the power loss of the radiator into account Aiming at this problem, the authors designed an equipment of measuring the actual output power of the microwave hyperthermia apparatus. A new method is proposed for calibration the output microwave power of microwave hyperthermia apparatus. Methods: The magnetron anode current was maintained at a default value by a control system. The microwave power generated by microwave source is coupled firstly to a low-power meter by the coaxial cable to measuring the power going through coaxial cable (P_(coaxial cable)). Then the microwave radiator is connected to the coaxial cable to make the microwave radiated by radiator. The radiator is assembled in the experimental device for the microwave completely absorbed by the water. The absorbed microwave energy of the water is calculated by measuring the water temperature change. The energy loss of the experimental device is calculated using the cooling rate. The output power of the radiator is equal to the ratio of the sum of the two aforementioned energy and the time. And the efficiency of the radiator η_(radiator), is equal to P_(radiator)/P_(coaxial cable) Results: The relationship between the actual output power of the microwave hyperthermia apparatus and the mag- netron anode current is P_(radiator) = 2η_(radiator) I. The efficiency of the radiator is η_(radiator)= (34±1)%. Conclusion: From the experimental results, the current method for calibration output power of microwave hyperthermia apparatus is defective, it dose not consider the conversion efficiency of radiator. Using the calibration method introduced in this paper, wecan accurately deter- mine the actual output power of microwave hyperthermia Apparatus.