NGD Analysis of Defected Ground and SIW-Matched Structure

An innovative design of bandpass (BP) negative group delay (NGD) passive circuit based on defect ground structure (DGS) is developed in the present paper. The NGD DGS topology is originally built with notched cells associated with self-matched substrate waveguide elements. The DGS designmethod is introduced as a function of the geometrical notched and substrate integrated waveguide 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 BP NGD function performances were validated with3-D simulations and measurements with -1.69 ns NGD value around 2 GHz center frequency over 33.7 MHz NGD bandwidth with insertion loss better than 4 dB and reflection loss better than 40 dB.