一般RFQ的适宜工作频率为50-400MHz,工作频率提升到大于1GHz，会使RFQ体积缩小，但将会带着诸多物理问题：在动力学上，横向聚集会减弱，束流传输效率难以保证；腔体尺寸会减小，加工和准直精度要求会提高；接受度会变小，上游束流与RFQ匹配难度会增加。电磁结构上，电压调谐敏感度会降低，场调平会更困难；分路阻抗和品质因子会下降，功率损耗会增加；热形变会更严重，工作频率难以控制。本项目通过模拟计算，主要针对RFQ工作频率提升所带来的横向动力学和电磁结构新问题进行研究，提出可行的降低和预测其影响的方法。其次研究RFQ作为直线注入器的共性匹配问题。本项目的研究旨在探索工作频率大于1GHz RFQ的动力学和高频特性，形成可靠的满足S波段直线加速器注入器要求的RFQ物理设计。高工作频率的RFQ作为S波段直线加速器注入器，将会使整个直线加速器的体积缩小，造价大幅度降低，提高其应用到医疗领域的可能性。

The suitable working frequency of RFQ is 50-400 MHz. If the working frequency is increased to more than 1 GHz, the volume of RFQ will be reduced, but there will be many physical problems: in dynamics, the transverse focusing will be weakened, the beam transmission efficiency will be reduced; the cavity size will be reduced, the requirements of machining and alignment accuracy will be improved; the acceptance will be reduced, and the matching difficulty between upstream beam and RFQ will be increased. In electromagnetic structure, the sensitivity of voltage tuning will be reduced, and tuning will be more difficult; shunt impedance and quality factor will be reduced, power loss will increase; thermal deformation will be more serious, and operating frequency will be difficult to control. Through the simulation calculation, this project mainly studies the new problems of transverse dynamics and electromagnetic structure caused by the increase of RFQ working frequency, and puts forward feasible methods to reduce and predict its impact. Secondly, the common matching problem of RFQ as linear injector is studied. The purpose of this research is to explore the dynamic and high frequency characteristics of RFQ with working frequency greater than 1 GHz, and to form a reliable RFQ physical design that meets the requirements of S-band linear accelerator injector. As an injector of S-band linear accelerator, RFQ with high operating frequency will reduce the volume and cost of the linear accelerator, and increase the possibility of its application in medical field.