NGD Analysis of Defected Ground and SIW-Matched Structure

A bandpass negative group delay (NGD) passive circuit based on defect ground structure (DGS) and substrate integrated waveguide (SIW)-matched is developed in the paper. The NGD DGS topology is originally built with notched cells associated with self-matched substrate waveguide elements. The DGS design method is introduced as a function of the geometrical notched and SIW via elements. Then, parametric analyses based on full wave 3-D electromagnetic $S$ -parameter simulations were considered to investigate the influence of DGS physical size effects. The design method feasibility study is validated with fully distributed microstrip circuit prototype. Significant bandpass NGD function performances were validated with 3-D simulations and measurements with −1.69 ns negative group delay value around 2 GHz center frequency over 33.7 MHz NGD bandwidth. Insertion loss is 4.37 dB, and reflection loss reaches 41.5 dB.