宽频带四端口馈源网络系统设计

展宽现有卫星通信频段的带宽是增大通信容量的有效途径之一。为将C波段通信接收频段带宽展宽为3.625~4.800 GHz，发射频段展宽为5.850~7.025 GHz，该文设计了一种宽频带、结构紧凑、双线极化四端口馈源网络系统，通过采用宽带正交模耦合器与E面侧壁耦合T-接头宽带频率双工器，拓宽了馈源网络的工作带宽，由于该工作频带超过了标准波导的工作带宽，网络各部件的设计采取了非标波导，该文设计了八边形过渡波导解决了系统各部件在整个频带内的匹配问题。研发和测试了该馈源网络系统，测试与仿真结果吻合良好。实测结果表明，所有端口电压驻波比小于1.35，插入损耗小于0.5 dB，收发隔离度大于95 dB。

Design of Broadband 4-port Feed Network System

With the development of satellite communication technology, the demand for communication capacity is increasing. Broadening existing communication bandwidth is a key technology of satellite communication antenna. In order to extend the C band satellite communication, covering the receiving band 3.625~4.800 GHz and the transmitting band 5.850~7.025 GHz, a compact broadband four-port dual linear polarization feed network is designed. The broadband characteristics are achieved by employing a broadband orthomode transducer and two identical E-plane side coupling T-junction duplexers. The extended C band exceeds the bandwidth of a standard rectangular waveguide, so an octave bandwidth concept for compact waveguide transitions based on the use of octagonal-shaped sections is presented. A prototype of the feed network is developed. Simulated and measured results show good agreements. Measurements show that, this compact 4-port network provides Voltage Standing Wave Ratio (VSWR) better than 1.35 in all ports, insertion losses less than 0.5 dB, isolation Tx/Rx greater than 95 dB.