This paper reports on quasi-elliptic dual-band bandpass filters (BPFs) that were designed for the Filter Student Design Competition of the 2019 European Microwave Week. The proposed lumped-element (LE) BPF concept is based on two dual-band transversal cells and one multi-resonant cell that allow the realization of symmetric and asymmetric dual-band transfer functions shaped by six poles and five transmission zeros. A compact implementation scheme based on LE series resonators is proposed for size compactness and wide spurious free out-of-band response. For proof-of-concept demonstration purposes, a dual-band LE prototype with two passbands centered 1 and 1.5 GHz was designed, manufactured, and measured. It exhibited the following radio frequency measured performance characteristics. Passbands centered at 1.02 and 1.45 GHz, minimum insertion loss levels of 2.0 and 2.7 dB, and bandwidth of 146 and 105 MHz, respectively, for the first and the second passband, and out-of-band rejection >30 dB between 0 and 894 MHz, 1.17–1.34 GHz, and 1.72–6.9 GHz.

中文翻译：

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基于串联级联多谐振单元的准椭圆双频带带通滤波器

本文报道了为 2019 年欧洲微波周滤波器学生设计竞赛而设计的准椭圆双频带带通滤波器 (BPF)。所提出的集总元件 (LE) BPF 概念基于两个双频带横向单元和一个多谐振单元，允许实现由六个极点和五个传输零点形成的对称和非对称双频带传递函数。提出了一种基于 LE 系列谐振器的紧凑实现方案，以实现尺寸紧凑和宽无杂散带外响应。出于概念验证演示的目的，设计、制造和测量了具有两个以 1 和 1.5 GHz 为中心的通带的双频带 LE 原型。它表现出以下射频测量的性能特征。通带以 1.02 和 1.45 GHz 为中心，