Synthesis Method of Broadband Spatial Power Combiner Based on Mirror System

In this article, the synthesis method to design a spatial power combiner by reflecting mirrors is presented. For a broadband power combination, the mirrors are designed using a two-frequency optimization method, which is facilitated by a segmenting-and-regrouping process to achieve the near-field coupling of wave modulation at different frequencies. The effect on bandwidth performance led by the segmenting operation is studied, with a specific focus on two key parameters, including the frequency interval and the partition size, to uncover an optimal design approach. Following the synthesis method, a 2-to-1 spatial power combiner is developed based on the proposed method. The simulation results show that the spatial power combiner can obtain a high-purity Gaussian output around 95% with a broad fractional bandwidth of 43.0%. To further validate the synthesis method, the designed spatial power combiner is fabricated and tested by radiation field measurements. The results are consistent with the simulation ones, where the high purity of the Gaussian output is verified. The proposed synthesis method can significantly improve the bandwidth of the spatial power combination system, and it can also be utilized for other designs of components involving beam modulation, such as mode converters or beam generators.