Baseband NGD circuit with RF amplifier

This presented report deals with the synthesis of baseband negative group delay (NGD) RF circuits. A theoretical approach based on the S-parameter analysis is presented. The NGD circuit synthesis formulae according to the desired gain value, NGD level and bandwidth are established. To validate the theoretical approach, a two-stage NGD device employing LNAs was investigated. Baseband NGD with minimal value below -1-ns with 400-MHz frequency bandwidth was found. The synthesised circuit presents a gain higher than 5-dB. To highlight the functionality of the NGD effect, time-domain analysis was performed. The NGD circuit allows the reduction of signal pure delays caused by telecom devices and is useful for the correction of interleaved symbols in RF/digital numerical systems.