A Compact Negative Group Delay Circuit Topology Based on Asymmetric Coplanar Striplines and Double-Sided Parallel Striplines

An innovative negative group delay (NGD) circuit topology based on asymmetric coplanar striplines (ACPSs) and double-sided parallel striplines (DSPSs) is proposed. The original NGD circuit topology consists of two sections of ACPS, one section of open-circuited DSPS, a connecting hole, and a group of grounding holes. The NGD characteristic is achieved by the open-circuited DSPSs combined with the connecting hole. To verify the proposed NGD circuit topology, a prototype is designed, fabricated, and measured. From the measured results, an NGD time of -2.42 ns at the center frequency of 1.577 GHz is obtained with an NGD bandwidth of 36MHz (1.561-1.597 GHz). The insertion loss is less than 4.75 dB with the return loss larger than 11.7 dB in the NGD band.