短波大功率宽带并联谐振腔巴伦的研究与设计

Investigation and design of a short-wave high power wideband balun with parallel resonant cavity

为了解决大功率短波广播发射天线的不平衡馈电和阻抗不匹配问题,提出了一种短波大功率宽带并联谐振腔巴伦。该巴伦采用谐振腔与同轴传输线的并联结构,同时实现了不平衡-平衡转换和阻抗变换。通过理论分析和全波电磁仿真的相互验证,完成了巴伦的设计和优化。仿真结果表明:工作频率范围是5~26.1 MHz(相对带宽为135.7%),阻抗变换比为1∶4,电压驻波比保持在1.5以下,插入损耗小于0.2 dB,相位不平衡小于2°,幅值不平衡小于0.5 dB,并且可承受500 kW以上的输入功率。该巴伦具有工作频带宽、传输效率高、辐射损耗低、平衡性能良好和承受功率大的特点,能够应用于大功率短波广播发射天馈线系统。

In order to solve the problems of unbalanced feeding and mismatched impedance of high-power short-wave broadcast transmitting antenna,a short-wave high power wideband balun with parallel resonant cavity was proposed.Based on the parallel structure of the resonant cavity and coaxial transmission line,the balun achieves the unbalanced-balanced conversion and the transformation of the impedance.Through mutual verification of theoretical analysis and full-wave electromagnetic simulation,the balun was designed and optimized.The simulation results show that the operating frequency range is 5~26.1 MHz(the relative bandwidth is 135.7%),the impedance transformation ratio is 1∶4,the voltage standing wave ratio is kept below 1.5,the insertion loss is less than 0.2 dB,the phase imbalance is less than 2°,the amplitude imbalance is less than 0.5 dB,and it can withstand the input power more than 500 kW.With the advantages of wide operating frequency range,high efficiency of transmission,low radiation loss,great performance of balance and the highpower compatibility,this balun can be applied to high power short-wave broadcast transmitting antenna feeder system.