NGD Bandpass Distributed Circuit

This paper introduces the universal canonical transfer function of the band-pass negative group delay (NGD) circuit. Similar to the filter theory, the band-pass NGD topologies can be established from low-pass to band-pass frequency transform. The basic characteristics of the NGD topology are described. The feasibility of the presented theory is concretized with a topology of fully distributed passive cell constituted by an open-ended parallel stub. The NGD level and bandwidth are analytically expressed by considering the stub RLCG model. A microstrip circuit is considered as a proof of concept (POC). As expected in theory, band-pass NGD is obtained with 10-GHz center frequency. The POC generates NGD level of about -200-ps over more than 2-GHz bandwidth. In the future, thanks to theory simplicity and the topology integrability, the NGD band-pass principle can be potentially useful for the improvement of RF/microwave circuits.