Microwave Power Combiner

The intention of this subject is to investigate a high-power microwave power combiner. It can provide both high-power circular and rectangular wave-guide microwave resource for the microwave chemistry reactions. So we use some microwave magnetrons as the power combiner resources, and feed them into the circular wave-guide or the rectangular wave-guide respectively. According to the results of our theoretical analysis and numerical calculation, we adjusted the probes' locations properly so that the power combiner can be realized. The main contents included in this thesis are shown below. Firstly, the method of microwave equivalent circuit is introduced. The mode voltage and mode current in a cylindrical wave-guide and the mode function in a circular wave-guide are analyzed in detail. The formulas of input impedance of coaxial line to circular wave-guide are derived, and the experimental data to verify the theoretic results are listed. Secondly, vector potential function as well as wave function and its boundary conditions are introduced to discuss the radiation field distribution of coaxial probe in circular wave-guide. The reaction concept and reciprocity theorem are combined with the consumption of filamentary current to derive the expressions of probes' mutual impedance in a circular wave-guide. Then some parameters are chosen, and the numerical calculations are carried out. Some curves about the mutual impedances' varieties are obtained. Thirdly, the method of microwave equivalent circuit is used to derive the input impedance formulas of single probe exciting rectangular wave-guide. Through numerical calculations, the corresponding curves of the input impedance are plotted. Then the mutual impedance between two probes that locate in the center of the wide wall of the rectangular wave-guide is discussed by means of the reaction concept. Finally, the steps as well as the results of the experiments are given. After establishing the experiment system, we finish the measurements of the power combiner. The results show that the power combination efficiency of the microwave power combiner arrives at a satisfactory result.