A novel dual-band negative group delay (NGD) circuit employing an active stepped-impedance structure is presented in this letter. A theoretical analysis on the dual-band NGD response of the proposed structure is presented. The characteristic impedances and phases of the transmission lines are calculated to implement the circuit’s I/O transmission function. This calculation is performed by defining the desired NGD values at two arbitrary frequencies as the operating condition. The theoretical analysis demonstrates that there is no dependence between the group delay (GD) values at different frequencies. Prototypes of the proposed circuit with the same or different GDs are designed, fabricated, and measured to demonstrate the performance of the proposed structure. The experimental results show that the proposed dual-band NGD circuit is capable of generating −1 ns GD at 0.7 and 1.3 GHz or different GDs (−0.3 and −2 ns). The corresponding maximum and minimum transmission gains are 2 and −8 dB, respectively.

中文翻译：

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一种新型的阶梯阻抗结构双频负群延迟电路


这封信中提出了一种采用有源阶梯阻抗结构的新型双频带负群延迟（NGD）电路。对所提出结构的双频带 NGD 响应进行了理论分析。计算传输线的特性阻抗和相位来实现电路的I/O传输功能。该计算是通过将两个任意频率处的所需 NGD 值定义为操作条件来执行的。理论分析表明，不同频率下的群延迟（GD）值之间不存在依赖性。设计、制造和测量具有相同或不同 GD 的所提出电路的原型，以证明所提出结构的性能。实验结果表明，所提出的双频 NGD 电路能够在 0.7 和 1.3 GHz 下生成 -1 ns GD 或不同的 GD（-0.3 和 -2 ns）。相应的最大和最小传输增益分别为2和-8dB。