Band Pass Negative Group Delay demonstration on a VHF RLC parallel passive lumped circuit

Abstract

This paper demonstrates the bandpass (BP) negative group delay (NGD) function on a passive RLC-parallel lumped network at Very High Frequencies (VHF). After the topological description of the RLC cell, the BP NGD analysis is introduced. The NGD circuit is modelled theoretical by means of voltage transfer function (VTF) expression. The analytical equations illustrating the BP NGD specifications as the NGD center frequency, NGD value, NGD bandwidth and the VTF attenuation are established in function of the R, L and C component parameters. A proof of concept is designed, fabricated as a SMD on printed circuit board, and measured. As expected, the different models (calculated, simulated and measured) present a BP NGD and are significantly corelated. The POC prototype (resp the calculated and simulated model), presents an NGD value of - 8 ns (resp -12 ns) and attenuation of - 10 dB (resp -8 dB) around a 225 MHz (resp 240 MHz) NGD center frequency. Uncertainties analysis (UA) of BP NGD specifications is also studied in order to show the influence of quality and tolerance of components for NGD circuit. The theoretical formulas of NGD specification UAs in function of R, L and C tolerances are derived. UAs with respect to 1%, 2% and 5% relative tolerances of R, L and C components constituting the POC designed circuit are performed.