An FET-based microwave active circuit with dual-band negative group delay

Abstract

Recent studies proved that certain electronic active circuits are capable to exhibit simultaneously a negative group delay (NGD) and amplification in microwave frequency bands. One of the simplest topologies generating this counterintuitive NGD function effect is formed by a series RLC-network in cascade with a transistor. By using this cell, similar to the classical electronic functions, dual-band NGD microwave devices with loss compensation possibility can be designed. Theoretic demonstrations concerning the theory of the NGD circuit considered are presented. The dual-band NGD concept feasibility is concretely illustrated by an example of EM/circuit co-simulations. So, in frequency domain, dual-band NGD with minimal values of about-1 ns was observed simultaneously within two frequency bands centered at about 1.05 GHz and 2.05 GHz. To highlight the functioning of the hybrid device considered, time-domain analysis showing the RF/microwave signal advancement is performed. As application, the concept investigated can be envisaged for data synchronization in multi-channel wireless communication systems eventually degraded by undesired EMI effects.

Neutralization of LC- and RC-Disturbances with Left-Handed and NGD Effects

“…In this section, we propose a cancellation technique of the resonance effect essentially modelled by parallel LC-network. To do this, the microwave NGD circuit formed by a transistor associated with RLC series network developed in [41][42] is used. Fig.…”

“…So, the applications are still limited in low frequencies. To overcome this physical roadblock, more recently, NGD active topologies for microwave signals were proposed [41][42][43][44]. These active topologies are constituted by RF transistor or amplifier associated with passive lumped networks.…”

Synthesis of RF Circuits with Negative Time Delay by Using LNA

“…Theoretical and experimental analyses confirm that this innovative physical function allows to generate an output signal with wave fronts propagating in advance of its input under certain conditions [7][8][9][10][11][12][13][14]. Inversely to the ordinary medium, in this case, the time delay can be assumed as negative [4][5][9][10][11][12][13][14][15][16]. It was pointed out [19][20] that this NGD effect does not forbid the causality principle.…”

“…Recent studies revealed that certain passive [1][2][3][4][5][6][7][8] and active [9][10][11][12][13][14][15][16][17][18] circuits are susceptible to exhibit the negative group delay (NGD) function at low-and RF-/microwavefrequencies. Theoretical and experimental analyses confirm that this innovative physical function allows to generate an output signal with wave fronts propagating in advance of its input under certain conditions [7][8][9][10][11][12][13][14].…”

“…To overcome this limitation, active microwave topologies based on the RF/microwave transistors have been developed [14][15][16][17][18][21][22]. Then, different applications of the NGD function were proposed in the literature.…”