Conversion Rules Between X-Parameters and Linearized Two-Port Network Parameters for Large-Signal Operating Conditions

Essaadali, Riadh; Jarndal, Anwar; Kouki, Ammar B.; Ghannouchi, Fadhel M.

doi:10.1109/tmtt.2018.2863227

Cited by 10 publications

(8 citation statements)

References 11 publications

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“…From the derived model, we conclude that a target described by a dynamic nonlinear transfer-function cannot be described by just one parameter. Instead, it has to be quantified by a collection of frequency-domain symmetrized Volterra kernels, as they result from the derivations shown in here (i.e., (14) and ( 20)). By computing images using conventional algorithms, it is possible to generate a visual representation of a measurement scene and the targets within, however, the computed quantity has no direct meaning or interpretation.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

On Dispersion and Multipath Effects in Harmonic Radar Imaging Applications

2021

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In harmonic radar applications, images produced using algorithms of conventional radar applications experience some defocusing effects of the electronic targets’ impulse responses. This is typically explained by the dispersive transfer functions of the targets. In addition, it was experimentally observed that objects with a linear transfer behavior do not contribute to the received signal of a harmonic radar measurement. However, some signal contributions based on a multipath propagation can overlay the desired signal, which leads to an undesired and unusual interference caused by the nonlinear character of the electronic targets. Here, motivated by the analysis of measured harmonic radar data, the effects of both phenomena are investigated by theoretical derivations and simulation studies. By analyzing measurement data, we show that the dispersion effects are caused by the target and not by the measurement system or the measurement geometry. To this end, a signal model is developed, with which it is possible to describe both effects, dispersion and multipath propagation. In addition, the discrepancy between classic radar imaging and harmonic radar is analyzed.

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Section: Discussionmentioning

confidence: 99%

“…Describing nonlinear electronic circuit elements is known in the engineering literature. There exist some methods to treat these devices similar to S-Parameters [14]. One of the more widely known descriptions are X-Parameters [15] or the poly-harmonic distortion modeling [16].…”

Section: Introductionmentioning

confidence: 99%

On Dispersion and Multipath Effects in Harmonic Radar Imaging Applications

2021

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“…Similar frameworks to X-parameters include "S-functions" [12]- [14]. Although X-parameters can be black-box models of nonlinear devices and circuits [15], [16], applications of X-parameters toward analytic design or modeling of nonlinear circuits and devices have recently made great progress [17]- [27]. Dunsmore described the findings of [22] as "a breakthrough" (p. 427 of [28]).…”

Section: Introductionmentioning

confidence: 99%

Signal-Flow-Graph Analysis of Weakly Nonlinear Microwave Circuits around a Large-Signal Operating Point

Amakawa¹,

Sugimoto²,

Tokgoz³

et al. 2023

Preprint

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<p>Signal flow graph (SFG) representation of small-signal responses of nonlinear microwave circuits around a large-signal operating point is developed using the X-parameters. It is shown that, unlike the SFGs for linear circuits, negative-frequency nodes need to be included explicitly. The development elucidates the circuit-operational meaning of the elusive T-type small-signal X-parameters, which represent interaction between positive- and negative-frequency components. As an example, such an SFG is used to derive a closed-form expression of the output power of an amplifier as a function of the load reflection coefficient. It is then used to plot approximate load-pull power contours. The result is consistent with the expressions of the optimum load reflection coefficient derived by Root et al. (EuMIC 2017) and of power contours derived by Peláez-Pérez et al. (TMTT 2013). SFGs provide an alternative systematic means to derive closed-form expressions in terms of X-parameters and to gain illuminating insights into the workings of weakly nonlinear circuits. </p>

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“…Although X-parameters can be black-box models of nonlinear devices and circuits [13], [14], applications of Xparameters toward analytic design or modeling of nonlinear circuits have recently made great progress [15]- [22]. The contribution of this paper is to demonstrate how SFGs can be adapted to the X-parameter framework.…”

Section: Introductionmentioning

confidence: 99%

Signal-Flow-Graph Analysis of Weakly Nonlinear Microwave Circuits around a Large-Signal Operating Point

Amakawa¹,

Sugimoto²,

Tokgoz³

et al. 2023

Preprint

View full text Add to dashboard Cite

Signal flow graph (SFG) representation of small- signal responses of nonlinear microwave circuits around a large-signal operating point is developed using the X-parameters. It is shown that, unlike the SFGs for linear circuits, negative-frequency nodes need to be included explicitly. The development elucidates the circuit-operational meaning of the elusive T-type small-signal X-parameters, which represent interaction between positive- and negative-frequency components. As an application example, such an SFG is used to derive a closed-form expression of the output power of a power amplifier as a function of the load reflection coefficient. It is then used to plot approximate load-pull power contours. The result is consistent with and more general than the expression of the optimum load reflection coefficient derived analytically by Root et al. (EuMIC 2017). SFGs provide a systematic means to derive closed-form expressions in terms of X-parameters and to gain illuminating insights into the workings of weakly nonlinear circuits.

show abstract

Conversion Rules Between X-Parameters and Linearized Two-Port Network Parameters for Large-Signal Operating Conditions

Cited by 10 publications

References 11 publications

On Dispersion and Multipath Effects in Harmonic Radar Imaging Applications

On Dispersion and Multipath Effects in Harmonic Radar Imaging Applications

Signal-Flow-Graph Analysis of Weakly Nonlinear Microwave Circuits around a Large-Signal Operating Point

Signal-Flow-Graph Analysis of Weakly Nonlinear Microwave Circuits around a Large-Signal Operating Point

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