This article presents two types of planar/waveguide quasi-elliptic linear-phase filters using mixed cascade frequency-dependent triplets (FDTs) and extracted pole sections (EPSs). Specifically, we propose the circuit synthesis and planar/waveguide realization techniques for quasi-elliptic linear-phase filters using the cascaded FDT and EPS. The circuit synthesis for the proposed filters avoids the complex matrix rotation and special scaling procedures compared with the general matrix synthesis and is directly compatible with lumped-element-based integrated circuit design. Besides, it permits cascading of FDTs and singlet sections thus effectively forming the pseudo-elliptic filter with a linear phase. For physical realization, we present new TEM- and TE-mode coupling configurations, and therefore, the mathematical models can be realized in practice with simple and practical structures. Finally, we present the complete design procedures of the planar configuration cascading two FDTs and waveguide structure cascading two EPSs and FDT to validate the theory.

中文翻译：

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使用具有提取极截面的混合级联频率相关三元组的平面/波导准椭圆线性相位滤波器

本文介绍了两种使用混合级联频率相关三元组 (FDT) 和提取极截面 (EPS) 的平面/波导准椭圆线性相位滤波器。具体来说，我们提出了使用级联 FDT 和 EPS 的准椭圆线性相位滤波器的电路合成和平面/波导实现技术。与一般矩阵合成相比，所提出的滤波器的电路合成避免了复杂的矩阵旋转和特殊的缩放程序，并且与基于集总元件的集成电路设计直接兼容。此外，它允许 FDT 和单线段的级联，从而有效地形成具有线性相位的伪椭圆滤波器。对于物理实现，我们提出了新的 TEM 和 TE 模式耦合配置，因此，数学模型可以通过简单实用的结构在实践中实现。最后，我们展示了级联两个 FDT 的平面配置和级联两个 EPS 和 FDT 的波导结构的完整设计程序，以验证该理论。