A design of size-reduced negative group delay circuit using a stepped impedance resonator

A design method to reduce the size of the planar negative group delay circuit (NGDC) is proposed by using a stepped impedance resonator (SIR) concept. From the conventional transmission line resonator, an equivalent stepped impedance resonator with reduced size is derived. To validate the derivation, the reflection coefficient and group delay response are compared between the two types of one-port NGDC. Finally, the reflection topology NGDC using a stepped impedance resonator is fabricated and tested. Maintaining its intrinsic electric properties, total size of the circuit is reduced to 72% from its original size.