Abstract
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.
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This work was supported by the Natural Sciences and Engineering Research Council of Canada. Use of the facilities of the Advanced RF Systems Lab of the National Microelectronics and Photonics Testing Collaboratory are appreciated.
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Bridges, G.E., Kandic, M. Gain compensated symmetric loaded transmission line exhibiting bidirectional negative group delay. Appl. Phys. A 109, 1087–1093 (2012). https://doi.org/10.1007/s00339-012-7423-3
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DOI: https://doi.org/10.1007/s00339-012-7423-3