Highly Miniaturized Wideband Negative Group Delay Circuit Using Effective Negative Dielectric permittivity Stopband Microstrip Lines

In this paper, a effective negative dielectric permittivity (epsilon) phenomenon is used to obtain compact negative group delay circuit (NGDC). Rectangular complementary split ring resonator (RCSRR) etched on the ground of microstrip line (MSL) is utilized to stimulate this behaviour. Firstly, the desired location of the target delay (f(0)) is solely determined using the unit dimensions. Then, the target GD is fully controlled using external resistor (I?) connected across the external rectangle of the previously determined RCSRR. Design curves of the proposed structure are established and employed to design NGDC with GD of -5 ns at f(0) of 3.5 GHz. The designed NGDC accomplishes 62% size diminution compared to the smallest circuit size that has ever been achieved before. Moreover, 0.30 GHz zero NGD bandwidth (BW) is achieved. Excellent agreement is noticed between the simulation results of the proposed design and the measurements of the fabricated circuit.