Synthesis of RF Circuits with Negative Time Delay by Using LNA

Abstract

A demonstration of the negative time-delay by using active circuit topologies with negative group delay (NGD) is described in this paper. This negative time delay is realized with two different topologies operating in base band and modulated frequencies. The first NGD topology is composed of an RL-network in feedback with an RF/microwave amplifier. Knowing the characteristics of the amplifier, a synthesis method of this circuit in function of the desired NGD values and the expected time advance is established. The feasibility of this extraordinary physical effect is illustrated with frequency-and time-domain analyses. It is shown in this paper that by considering an arbitrary waveform signal, output in advance of about 7 ns is observed compared to the corresponding input. It is stated that such an effect is not in contradiction with the causality. The other NGD topology is comprised of a microwave amplifier associated with an RLC-series resonant. The theoretical approach illustrating the functioning of this NGD circuit is established by considering the amplifier Sparameters. Then, synthesis relations enabling to choose the NGD device parameters according to the desired NGD and gain values are also established. To demonstrate the relevance of the theoretic concept, a microwave device exhibiting NGD function of about -1.5 ns at around 1.19 GHz was designed and analyzed. The NGD device investigated in this paper presents advantages on its faculty to exhibit positive transmission gain, the implementation of the bias network and matching in the considered NGD frequency band.

New Analytical Approach to Estimate the Electromagnetic Spectrum From Devices Submitted to High Voltages

“…In order to optimize certain BP-NGD SMART SYSTEMS: THEORY AND ADVANCES CHAPTER I 12 performances as bandwidth, some mixed topologies as proposed in [55][56] were also designed. To compensate losses, BP-NGD active circuits using transistors or low-noise amplifier were introduced [59][60][61][62][63][64]. It was also investigated that there are possibilities to design multi-band BP-NGD circuits [64][65][66].…”

Investigation on four‐port mono‐capacitor circuit with high‐pass negative group delay behavior

“…Emphatically, intensive research works were done on low attenuation loss NGD passive circuits in the last two decades. [25][26][27][28][29][30] Nevertheless, the diversity of NGD circuit structures leads to think about the general topologies of the unfamiliar electronic function. Such a question motivates to initiate a fundamental circuit theory of NGD function inspired from filter function.…”

“…15,16 Despite the notable limitation reported on the NGD properties, 20 the existence of NGD effect in microwave frequencies was an open question. [21][22][23][24][25][26][27][28][29][30][31][32] Remarkable NGD microwave passive circuits were designed in early 2000s from metamaterial-based negative refractive index and split ring resonator structures. [21][22][23][24] However, the meta-material-based NGD passive circuits are significantly lossy and limit the opportunity of their applications.…”

“…Despite the notable limitation reported on the NGD properties, 20 the existence of NGD effect in microwave frequencies was an open question 21–32 . Remarkable NGD microwave passive circuits were designed in early 2000s from meta‐material‐based negative refractive index and split ring resonator structures 21–24 .…”

“…However, the meta‐material‐based NGD passive circuits are significantly lossy and limit the opportunity of their applications. Emphatically, intensive research works were done on low attenuation loss NGD passive circuits in the last two decades 25–30 . Nevertheless, the diversity of NGD circuit structures leads to think about the general topologies of the unfamiliar electronic function.…”