0IO-Shape PCB Trace Negative Group-Delay Analysis

This paper elaborates a negative group delay (NGD) analysis of 0IO-shape printed circuit board (PCB) traces. This circuit topology is originally implemented with a tri-coupled line (3CL) six-port element with the lateral side connected through lossy transmission lines (TLs). After description of the electrical equivalent diagram, the S-matrix model is established. The group delay (GD) is formulated from the transmission coefficient as a function of the 0IO topological parameters. The effectiveness of the GD modelling is verified with a microstrip circuit proof-of-concept (POC). Simulations and measurements, which are in good agreement, confirm the dual-band bandpass NGD behavior of the 0IO POC. The fabricated prototype generates NGD levels better than −1 ns at NGD center frequencies of about 2.2 GHz and 3 GHz. In addition, to this good NGD performance, the 0IO POC operates with a low insertion loss better than 2.5 dB and reflection losses better than 12 dB in the NGD bandwidths.