ABSTRACT In this paper, a novel design approach for microwave tunable balanced phase shifters with the common-mode (CM) suppression is proposed based on the liquid crystal (LC) technology. The proposed tunable balanced liquid crystal phase shifter (LCPS) is designed by the LC-based microstrip differential line with periodical T-shaped stubs, which supports the spoof surface plasmon polaritons (SSPP) mode. Thanks to the slow-wave characteristic induced by the SSPP mode, both tunable phase shifts and figure of merit (FoM) of the balanced LCPS are effectively enhanced. In addition, the defected ground structure based on slotted dumbbell-shaped resonators is also employed in this design and the CM suppression is integrated into tunable balanced phase shifters for the first time. Finally, the corresponding prototype is fabricated and tested to verify the above theoretical analysis. The measured results demonstrate that this proposed tunable balanced LCPS can simultaneously achieve tunable phase shifts with FoM of more than 12.4°/dB and the CM noise suppression of more than 17 dB attenuation from 2.5 to 5.5 GHz. Graphical abstract

中文翻译：

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基于具有共模抑制的欺骗表面等离子体激元的可调谐平衡液晶移相器

摘要 在本文中，提出了一种基于液晶 (LC) 技术的具有共模 (CM) 抑制功能的微波可调平衡移相器的新设计方法。所提出的可调平衡液晶移相器 (LCPS) 是由基于 LC 的微带差分线设计的，具有周期性的 T 形短截线，支持欺骗表面等离子体激元 (SSPP) 模式。由于 SSPP 模式引起的慢波特性，平衡 LCPS 的可调相移和品质因数 (FoM) 均得到有效增强。此外，该设计还采用了基于开槽哑铃形谐振器的缺陷接地结构，首次将共模抑制集成到可调平衡移相器中。最后，相应的原型被制造和测试以验证上述理论分析。测量结果表明，该提议的可调平衡 LCPS 可以同时实现 FoM 超过 12.4°/dB 的可调相移和 2.5 至 5.5 GHz 范围内超过 17 dB 衰减的 CM 噪声抑制。图形概要