This letter presents a novel design for a 3-D-printed circular waveguide dual-mode (CWDM) filter with a modified cavity shape. The modification leads to a wide spurious-free stopband, which is highly desirable for channel separation in waveguide contiguous output multiplexers (OMUXs) in satellite communication systems. The new resonant cavity design is a result of applying shape deformation to a basic circular cavity in order to move away and suppress parasitic modes. A fourth-order Ku-band channel filter with two transmission zeros (TZs) is designed, fabricated by additive manufacturing (AM) in one piece and measured. In comparison with the state-of-the-art design of a stepped CWDM filter, an improvement of approximately 35% wider spurious-free range is achieved.

中文翻译：

---

用于卫星通信系统的改进带外性能的圆波导双模滤波器

这封信介绍了一种新颖的 3D 打印圆形波导双模 (CWDM) 滤波器设计，其具有改进的腔体形状。这种修改导致宽的无杂散阻带，这对于卫星通信系统中的波导连续输出多路复用器 (OMUX) 中的通道分离是非常理想的。新的谐振腔设计是对基本圆形腔应用形状变形以消除和抑制寄生模式的结果。设计了具有两个传输零点 (TZ) 的四阶 Ku 波段信道滤波器，通过增材制造 (AM) 一体制造并进行了测量。与阶梯式 CWDM 滤波器的最先进设计相比，无杂散范围提高了约 35%。