A Novel Flat Broadband Passive Circuit with Negative Group Delay

A novel flat negative group delay circuit is proposed. The flatter negative group delay is achieved, and the insertion loss is reduced. The circuit structure consists of a resistor R1 series connected with a capacitor C1 and inductor L1 in parallel, followed by a capacitor C2 and inductor L2 in parallel, and finally connected in series with a capacitor C3 and inductor L3. The analysis design equation is provided. The effects of different component values on circuit flatness and bandwidth are analyzed. According to this design method, a flat negative group delay circuit is designed and fabricated. The simulation and measurement results are basically consistent. It has good flat negative group delay characteristics, with a group delay fluctuation of 3%, a group delay value of −1.02 ns, and an insertion loss of 7 dB. The feasibility of the design method is verified.