A novel reconfigurable negative group delay (NGD) circuit based on branch-line coupler is proposed in this article. It consists of two branch-line couplers that are connected by two varactors with different capacitance values. By simply adjusting the capacitance values, both the transmission gain/loss and group delay (GD) values of the proposed circuit can be independently adjusted as desired. Full theoretical analysis has been given to verify the reconfigurable NGD responses. To compensate for the transmission loss, an active NGD circuit is also proposed by inserting two simple amplifiers in the transmission paths. The active circuit can also achieve independent transmission gain/loss and GD by tuning the amplifiers’ gain with fixed capacitance value. Passive and active prototypes were designed, fabricated, and tested to demonstrate the proposed techniques. The experimental results show that NGD of the proposed passive circuit can be adjusted from 0 to −90 ns, while the gain varies from −14 to −53 dB. The GD of active circuit can also be adjusted from 0 to −80 ns, while the gain varies from 17 to −18 dB. These experimental results agree well with simulations.

中文翻译：

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具有独立群延迟和传输损耗/增益控制的新型可重构负群延迟电路

本文提出了一种基于支线耦合器的新型可重构负群延迟 (NGD) 电路。它由两个支线耦合器组成，这些耦合器由两个不同电容值的变容二极管连接。通过简单地调整电容值，所提出电路的传输增益/损耗和群延迟 (GD) 值都可以根据需要独立调整。已经给出了完整的理论分析来验证可重构的 NGD 响应。为了补偿传输损耗，还提出了通过在传输路径中插入两个简单放大器的有源 NGD 电路。有源电路还可以通过使用固定电容值调整放大器的增益来实现独立的传输增益/损耗和 GD。被动和主动原型被设计、制造、并进行测试以演示所提出的技术。实验结果表明，所提出的无源电路的 NGD 可以从 0 调整到 -90 ns，而增益从 -14 到 -53 dB 不等。有源电路的 GD 也可以在 0 到 −80 ns 范围内调整，而增益范围从 17 到 −18 dB 不等。这些实验结果与模拟非常吻合。