C波段卫星通信抗5G干扰滤波器小型化解决方案

C-band satellite communication anti-5G interference filter miniaturization solution

卫星通信的接收链路常会受到5G移动通信发射端的干扰,消除干扰的一个解决方案是在现有天馈系统中加入一个高抑制滤波器,引入传输零点来增大对指定频段的抑制。为了整个系统的紧凑性,滤波器小型化是必需的,而高性能与小型化之间往往存在矛盾。针对这一问题,一个C波段具有高带外抑制的同轴腔体滤波器被提出。由BJ-40标准波导直接输入耦合到多个谐振器减小尺寸实现小型化。通过非谐振节点和具有冗余谐振模式的三角结构不引入负耦合来产生低端传输零点,实现对无关信号的抑制,消除了滤波器低端零点的传统实现方式(负耦合)所带来的加工影响。设计的同轴腔体滤波器实现回波损耗<18 dB,带外抑制在3.5~3.6 GHz>37 dB,3.45~3.5 GHz>53 dB,3.2~3.4 GHz>60 dB,4.4~4.8 GHz≥70 dB,整体结构紧凑。该C波段滤波器结构简单无负耦合引入,易于加工,源耦合到多个谐振器紧凑结构,适用于卫星通信系统抗干扰应用。

The receiving link of satellite communication is often interfered by the transmitter of 5G mobile communication.One solution to eliminate interference is to add a high suppression filter to the existing antenna feed system,and introduce transmission zeros to increase the suppression of the specified frequency band.For the compactness of the whole system,filter miniaturization is necessary,but there is often a contradiction between high performance and miniaturization.To solve this problem,a C-band coaxial cavity filter with high out-of-band rejection is proposed.Direct input coupling from BJ-40 standard waveguide to multiple resonators to reduce size for miniaturization.Non resonant nodes and triangular structures with redundant resonant modes do not introduce negative coupling to generate low frequency transmission zeros to suppress irrelevant signals,which eliminates the processing impact of the traditional implementation of filter low end transmission zeros(negative coupling).The return loss of the designed coaxial cavity filter is greater than 18 dB.The out-of-band suppression is greater than 37 dB in 3.5~3.6 GHz,greater than 53 dB in 3.45~3.5 GHz,greater than 60 dB in 3.2~3.4 GHz and greater than 70 dB in 4.4~4.8 GHz.The whole structure is compact.The C-band filter has a simple structure without negative coupling introduction,is easy to process,and has a compact structure with source coupling to multiple resonators,making it suitable for anti-jamming applications in satellite communication systems.