Demonstration of negative signal delay with short-duration transient pulse

B. Ravelo

This paper introduces theoretic and experimental analyses of short-duration pulse propagation through a negative group delay (NGD) circuit. The basic analysis method of this electronic circuit operating in baseband and microwave frequencies is investigated. Then, its electrical fundamental characteristics vis-à-vis transient signals are developed. To validate the theoretic concept, planar hybrid devices with one- and two-stage NGD cells were designed, simulated, fabricated and tested. Transient analyses with ultra-wide band (UWB) pulse signals with different widths are realized. Then, experimental results in good agreement with the theoretical predictions were observed. Consequently, group delay going down under −2.5 ns is evidenced in baseband frequency up to 63 MHz with one-stage NGD cell. In time-domain, a Gaussian pulse in advance of about = −1.5 ns or 20% of its half-height time-width was measured. This corresponds to a negative group velocity of about = / = −0.13 ( is the physical length of the tested device and is light speed in the vacuum). More significant NGD value over 100-MHz bandwidth is stated with two-stage NGD cells. This results in a Gaussian pulse peak advance of about −5 ns (raising a group velocity of about = −0.12) or 31% of its half-height time-width. Finally, some potential applications based on the NGD function are discussed.

Mots clés: Physical Sciences

Domaines: Physique [physics]

B. Ravelo. Demonstration of negative signal delay with short-duration transient pulse. European Physical Journal: Applied Physics, 2011, 55 (1), ⟨10.1051/epjap/2011110038⟩. ⟨hal-00719807⟩