Dielectric Resonator Negative Group Delay Circuit

This study investigates an innovative theory on design of dielectric resonator (DR) based negative group delay (NGD) microwave circuit. The NGD circuit is mainly constituted by a cylindrical bulk of DR as a coupling element with a microstrip line. The developed theory is analytically established from the S-parameters modeling of this innovative DR NGD topology. The NGD analysis and synthesis equations are formulated by considering the key parameters of the DR NGD cell. The NGD existence condition as a function of the DR and microstrip line parameters is also introduced. The behavioral response of the bandpass NGD function is verified with different designed proof-of-concepts (POCs). The developed NGD DR topology was validated with original circuit design by commercial simulations and experimentations with insertion and reflection losses lower than 4 and 10 dB, respectively. The POC prototypes operate with low attenuation losses in mono band and dual bands up to 10 GHz. Single NGD cells with DR coupled with "I" and "U" shape microstrip lines operating at different central frequencies were designed and implemented. Then, dual-band NGD circuits operating at approximately 2.5 and 5 GHz were also tested. The possibility to widen the NGD bandwidth with double DR NGD circuits was investigated.