SSPP Transmission System With Negative Group Delay and Power Compensation

The advanced signal output based on negative group delay (NGD) plays a pivotal role in real-time communication and sensing applications. However, the implementation of NGD often results in significant signal attenuation. Spoof surface plasmon polariton (SSPP) units with tightly coupled structures are capable of generating NGD near the sidebands. Building on this principle, an NGD SSPP unit is proposed in this paper by utilizing tightly folded structures. The NGD SSPP unit is integrated into the classical SSPP waveguide with an H-shaped unit to control the transmission group delay. This waveguide configuration facilitates the advanced output of double-sideband modulation signals. Nevertheless, the generation of negative group delay is also typically accompanied by considerable transmission losses. To address this challenge, a low-noise amplifier is designed for power compensation. The SSPP waveguide with the NGD unit is then cascaded with the low-noise amplifier, resulting in an SSPP transmission system with power compensation for the NGD signal.