Synthesis of reflection type negative group delay circuit using transmission line resonator

Design equation and synthesis of reflection type negative group delay circuit (NGDC) using transmission line resonator (TLR) are presented. From the mathematical analysis, general equations are derived and validated with simulation for lumped element (LE) equivalent circuit. TLR-loaded reflection type NGDC is proposed to overcome the limited availability of component values required for LE structural NGDC. As a design example, single unit TLR-loaded NGDC with group delay (GD) of -8 ns is designed. Simulation results agreed pretty well with the proposed design equation. To obtain broadband negative group delay with rigid flatness specification, 2-stage reflection type TLR-loaded NGDC with total group delay of -7 ns, -1.7 dB loss, and 30 MHz bandwidth around 2 GHz, in which magnitude flatness of 0.1 dB and group delay flatness of 0.5 ns is maintained, are fabricated and demonstrated.