A Tunable Negative Group Delay Filter using Memristors

This paper presents a novel tunable transmission-line negative group delay (NGD) filter using memristors. The proposed filter is based on short-circuited coupled lines. The memristors with a wide tuning range are loaded in the coupling ports of corresponding coupled lines. The NGD characteristics of the proposed filter could be tuned by memristors, which could be controlled by a high-frequency voltage. The results show that the NGD variation is from −2.214 ns to −9.029 ns at the center frequency of 1.920 GHz. To enhance the NGD bandwidth, two NGD circuits (NGDCs) operating at slightly different center frequencies are connected in parallel.