, Volume 109, Issue 4, pp 1087-1093
Date: 15 Nov 2012

Gain compensated symmetric loaded transmission line exhibiting bidirectional negative group delay


A one-dimensional medium capable of bidirectional lossless negative group delay electromagnetic wave propagation is described. The medium is implemented as a microwave circuit comprising two symmetric resonator-loaded transmission lines, with active gain compensation and coupled through power combiners. We experimentally demonstrate the circuit is conditionally stable and is capable of lossless transmission of a finite bandwidth pulse in both directions. A measured group delay of −600 ps with a gain of 1.12 dB in both directions is achieved for a Gaussian pulse with a bandwidth of 14 MHz modulated at a frequency of 280 MHz (NGD-bandwidth-product of 0.0084). This circuit demonstrates the possibility of constructing a one-dimensional spatial void.