This article reports on the RF design and practical development of RF co-designed bandpass filters/isolators (BPFIs). They are based on series-cascaded nonreciprocal resonant stages, microwave resonators, and multiresonant cells. The nonreciprocal stages are shaped by an in-parallel cascaded transistor-based path and a transmission line (TL) that result in a zero-phase resonance in the forward direction and high isolation (IS) in the reversed one. The operating principles of the nonreciprocal resonant stage are presented through circuit analysis and coupled-resonator diagrams (CRDs) that facilitate their design with coupled-resonator-based filter design methods. Various CRD-synthesized examples of low- and high-order transfer functions with and without transmission zeros are shown. They demonstrate the applicability of the proposed method for alternative-type of filtering responses with and without gain in the forward direction and high levels of IS in the reversed one. For proof-of-concept demonstration purposes, five prototypes were designed, manufactured, and measured at $S$ -band.

中文翻译：

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使用不可逆谐振级和微波谐振器的RF共同设计的带通滤波器/隔离器

本文报告了射频设计和射频共同设计的带通滤波器/隔离器（BPFI）的实际开发。它们基于串联级联的不可逆谐振级，微波谐振器和多谐振单元。不可逆级由并联的基于晶体管的级联路径和传输线（TL）形成，传输线（TL）导致正向为零相位谐振，反向为高隔离（IS）。通过电路分析和耦合谐振器图（CRD）展示了不可逆谐振级的工作原理，这些图通过基于耦合谐振器的滤波器设计方法促进了其设计。显示了具有和不具有传输零的低阶和高阶传递函数的各种CRD合成示例。他们证明了所提出的方法适用于替代类型的滤波响应，在正向有增益和无增益，在反向有高IS的情况下。为了概念验证的目的，设计，制造和测量了五个原型， $ S $ -乐队。