一种紧凑型双频段横电磁波线性源馈电网络设计方法

A Compact Dual-Band Transverse Electromagnetic Wave Linear Source Feeding Network Design Method

摘要: 针对卫星通信天线小型化、高增益、口径复用的需求，设计一种工作在Ku (12.25~12.75 GHz)、Ka (19.6~21.2 GHz)的新型双频段横电磁波线性源馈电网络。网络包含：采用级联E-T结构的波导功分器，对比H-T结构缩短了横向尺寸；含有直角结构扭波导的模式转换器，扭波导长度仅为四分之一波长，且对比现有锐、钝角结构更易加工；将两频段生成的线性源组合的双工器，实现天线辐射体的单端口双频激励。仿真结果显示，Ku/Ka频段反射系数均优于−22 dB，传输系数分别优于−0.18 dB、−0.1 dB，隔离度分别优于−36 dB、−40 dB，合成波电场幅度波动范围分别为±1.5 dB、±0.8 dB，相位波动范围分别为±10 ˚、±8˚。新型双频馈电网络幅度波动为双平行板馈电系统的15%，避免了能量的锥削分布；横向尺寸约为H-T馈电网络的50%，实现了结构的紧凑设计。

Abstract: In response to the requirements of miniaturization, high gain, and aperture reuse of satellite communication antennas, a novel dual-band transverse electromagnetic wave linear source feeding network working in Ku (12.25~12.75 GHz) and Ka (19.6~21.2 GHz) bands is designed. The feeding network consists: a waveguide power divider that adopts a cascaded E-T structure that is shorter in the H-T lateral dimension; a mode converter containing a right twist waveguide that is easier to manufacture than acute or obtuse angle structures and is only one quarter of a wavelength in length; a duplexer that combines two sources generated in two frequency bands to achieve single-port dual-frequency excitation of an antenna radiator. The simulation results show that the reflection coefficients in the Ku/Ka frequency bands are better than −22 dB, the transmission coefficients are better than −0.18 dB and −0.1 dB respectively, the isolation levels are better than −36 dB and −40 dB respectively, the amplitude fluctuation range of the synthesized wave electric field is ±1.5 dB and ±0.8 dB respectively, and the phase fluctuation range is ±10˚ and ±8˚ respectively. The amplitude fluctuation of the novel dual-frequency feed network without tapering is 15% of that of the dual parallel-plate feed system; its compact lateral size is approximately 50% of that of the H-T feed network.