A Compact Transmission-Line Self-Matched Negative Group Delay Microwave Circuit

Abstract

A compact self-matched negative group delay (NGD) circuit without the need for an external matching circuit is proposed. The proposed NGD circuit is composed of two-port open-circuited coupled lines, a short-circuited transmission line and two resistors connected by two transmission lines. The coupled lines are utilized to obtain port matching. To verify the design concept, an NGD circuit with the size of $0.39\lambda _{g}\times 0.19\lambda _{g}$ is designed and fabricated. From the measurement results, NGD value of −8.75 ns at the center frequency of 1.570 GHz is obtained with NGD bandwidth of 3.82%, signal attenuation of less than 20.5 dB and return losses of more than 32 dB.