Low-pass Negative Group Delay Research Articles

Theory and circuit modeling of baseband and modulated signal delay compensations with low- and band-pass NGD effects

With the increase of the electrical interconnect network complexity, the signal integrity (SI) analysis becomes crucial for the electronic RF and mixed circuit designer. Approximated and optimized models of printed circuit boards (PCBs) electrical interconnect network were developed. However, interconnect effect correction techniques are still needed. The present paper addresses an example of correction technique of electrical interconnect for the PCBs. The feasibility of the concept is verified by considering a distributed transmission line (TL) latency and delay correction. The proposed correction technique is based on the use of the negative group delay (NGD) circuits. The theoretical approach including the NGD cell synthesis relations are established. The innovative low- and band-pass NGD topologies are suggested respectively for the baseband and modulated signal delay reduction. The fundamental characteristics of the low- and band-pass NGD cells are examined. The proposed technique is applied to the compensation of the microstrip interconnect line delay. It was found that the NGD effects enable to compensate the signal delay in baseband frequency up to hundreds MHz with low-pass NGD circuit and 2.45GHz modulated microwave signals with band-pass NGD circuit. In both cases, the possibilities to reduce the latency and delay of some nanoseconds (ns) are performed.

First‐order low‐pass negative group delay passive topology

An innovative theory on the passive circuits capable to generate low-pass negative group delay (NGD) behaviour is introduced. An identification method enabling to identify the first-order NGD simple cells built with resistor-inductor (RL)- and resistor-capacitor (RC)-networks is elaborated. The fundamental characteristics as the NGD level and cut-off frequency are formulated from the low-pass NGD circuit canonical transfer function. The NGD existence conditions are derived in function of the established topology parameters. Despite the attenuation systematically related to the passive cell nature, low-pass NGD behaviours with tens ns NGD level and tens MHz bandwidth were obtained with an example of lumped RL-network-based L-topology circuit. Transient analysis was performed to illustrate that the NGD phenomenon enables to exhibit baseband signal advance effect. The proposed NGD topology simplicity promises their potential applications especially in term of signal correction and the modern electronic system improvement.