Optimization of Circular Waveguide Microwave Sensor for Gas-Solid Two-Phase Flow Parameters Measurement

The microwave sensor is a key element of the microwave method for the gas-solid two-phase flow parameter measurement. The geometric size of the microwave sensor plays an important role on the transmiting, propagating and receiving of microwave signals, and thus on the signal quality. In this paper, the circular waveguide microwave sensor is optimized to achieve a minimum input reflection coefficient of the microwave propagating within the probe. The optimization is carried out at three operating frequencies of 5.8 GHz, 10 GHz and 24 GHz, by using the orthogonal experimental optimization method. Based on the extensive simulation results, it is concluded that the optimal sensor size is inversely proportional to the operating frequency. Experimentally, the rationality of the probe structure optimization is verified by measuring the received signal strength. Experimental tests are also conducted to evaluate the performance of the optimized sensor. Results show that the optimized sensor gives a highly received signal at the corresponding operating frequency. The numerical and experimental results indicate that the orthogonal experiment method is feasible for optimizing the microwave sensor probe, which provides a basis for the performance improvement of microwave sensor to measure the gas-solid flow.