Nonlinear Mutual Coupling Compensation Operator Design Using a Novel Electromagnetic Machine Learning Paradigm

Alzahed, Abdelelah M.; Mikki, Said; Antar, Yahia M. M.

doi:10.1109/lawp.2019.2903787

Cited by 62 publications

(41 citation statements)

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“…Therefore, when two antennas (Tx and Rx) are placed next to each other, the individual Tx and Rx ACGFs used in formulae like those to be derived in this paper already account in full for the impact of mutual coupling between antennas, regardless to separation and distance between the coupled elements. This was demonstrated by good computational and experimental results in works like [14,15,20,21,25], mostly in the frequency domain; while some results in the time domain were given in [18,19], more data will be provided in §4a.The purpose of the present work is to explore several applications of the recently introduced ACGF approach [7-25] for communication systems research at a very general and fundamental level. The intention here is investigating new methods for performing wireless communication when the impact of the antenna on the digital link performance is explicitly taken into account.…”

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confidence: 95%

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The antenna spacetime system theory of wireless communications

Mikki

2019

Proc. R. Soc. A.

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A general deterministic spacetime system theory of antennas suitable for the analysis and design of wireless communication links is rigorously developed using the recently introduced antenna current Green's function formalism. We provide the first complete derivation of the antenna spatio-temporal response to a delta source using only electromagnetic Green's functions, effectively eliminating all field and current distributions in the final expressions. While the theory works well in both space and time, it puts into sharper focus how the spatio-temporal structure of electromagnetic processes imposes restrictions on the signal processing capabilities of antenna systems by constraining the allowable mathematical form of the effective impulse response of the global wireless communication link. It is shown that the antenna current Green's functions of both the receive and transmit terminals, plus the propagation environment Green's functions, are the only quantities needed to obtain the single input-single output link response function in closed form. One of the results deduced from the theory is that an exact impulse response cannot be ascribed to an arbitrary antenna in general, but may be approximated for many applications. The theory can be deployed for future antenna systems research to boost up spectral efficiency (without increasing physical bandwidth) by directly incorporating electromagnetic knowledge into the design of the communication system's signal processing functions.royalsocietypublishing.org/journal/rspa Proc. R. Soc. A 475: 20180699 treated in parallel [1][2][3][4][5][6][7]. For example, some recent book-length treatments of such interdisciplinary topic appear to address issues pertinent to a unified electromagnetic/communicationtheoretic formalism [5][6][7]. Several research articles have also been published in this domain, e.g. see [2,3] (a non-exhaustive list; however, see [5] for an extensive literature on electromagnetic information theory). Owing to the increasing complexity of 5G and other future communication systems, it is no longer possible to separate the study of the physical layer to purely signal processing and purely electromagnetic parts. Indeed, each process is now expected to feed on the other, and for that reason, there is a need to reexamine the subject at the broadest and most comprehensive theoretical level possible, especially in light of some recent advances in fundamental research. As a step toward this goal, the antenna current Green's function (ACGF) [7] was recently introduced as a frequency-domain spatial transfer function method capable of providing an alternative approach to applied electromagnetics more in line with signal processing and communication theory [8,9]. The ACGF formalism is a complete exact electromagnetic generalization of the idea of the 'impulse response' of antenna systems. It was formulated recently in [7-25] using a hybrid approach incorporating functional analysis, distribution theory, differential geometry into electromagnetic theory. Although t...

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“…whereḠ(r − r ; t − t ) is the free-space (forward) time-dependent dyadic Green's function, see detailed expressions in [28]. 15 In the presence of other scatterers and objects in the environment,…”

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The antenna spacetime system theory of wireless communications

Mikki

2019

Proc. R. Soc. A.

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“…Expediting design procedures that require repetitive references to the EM model has been the subject of extensive research over the recent years. Available solutions include incorporation of adjoint sensitivities into gradientbased routines [11], [12], algorithmic improvements of conventional methods (e.g., suppression of finite-differentiation sensitivity updates [13], [14]), exploring response features (e.g., [15], [16]), or utilization of surrogate models, both physics-based (space mapping [17], manifold mapping [18], adaptive response scaling [19]) and data-driven (response surfaces [20], kriging [21], neural networks [22]), as well as machine learning techniques [23], [24].…”

Section: Introductionmentioning

confidence: 99%

Antenna Modeling Using Variable-Fidelity EM Simulations and Constrained Co-Kriging

Pietrenko‐Dabrowska

Koziel

2020

IEEE Access

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Utilization of fast surrogate models has become a viable alternative to direct handling of full-wave electromagnetic (EM) simulations in EM-driven design. Their purpose is to alleviate the difficulties related to high computational cost of multiple simulations required by the common numerical procedures such as parametric optimization or uncertainty quantification. Yet, conventional data-driven (or approximation) modeling techniques are severely affected by the curse of dimensionality. This is a serious limitation when it comes to modeling of highly nonlinear antenna characteristics. In practice, general-purpose surrogates can be rendered for the structures described by a few parameters within limited ranges thereof, which is grossly insufficient from the utility point of view. This paper proposes a novel modeling approach involving variable-fidelity EM simulations incorporated into the recently reported nested kriging modeling framework. Combining the information contained in the densely sampled lowand sparsely sampled high-fidelity models is realized using co-kriging. The resulting surrogate exhibits the predictive power comparable to the model constructed using exclusively high-fidelity data while offering significantly reduced setup cost. The advantages over conventional surrogates are pronounced even further. The presented modeling procedure is demonstrated using two antenna examples and further validated through the application case studies. INDEX TERMS Antenna design, surrogate modeling, kriging interpolation, co-kriging, electromagnetic (EM) simulation.

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“…Others include response correction methods, e.g., manifold mapping [44] or adaptive response scaling [45]. Popular solutions for global search are data-driven surrogates [46] and machine learning techniques [47], often combined with sequential sampling procedures [48], where construction of the surrogate is interleaved with prediction stages leading to a generation of infill points and identifying the promising regions of the search space [49]. Robust design can be also aided by approximation surrogates, with a notable example of polynomial chaos expansion (PCE) models [50], which have the advantage of estimating the statistical moments of the system outputs without the necessity of running Monte Carlo analysis [51].…”

Section: Introductionmentioning

confidence: 99%

Improved-Efficacy Optimization of Compact Microwave Passives by Means of Frequency-Related Regularization

2020

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Electromagnetic (EM)-driven optimization is an important part of microwave design, especially for miniaturized components where the cross-coupling effects in tightly arranged layouts make traditional (e.g., equivalent network) representations grossly inaccurate. Efficient parameter tuning requires reasonably good initial designs, which are difficult to be rendered for newly developed structures or when redesign for different operating conditions or material parameters is required. If global search is needed, due to either the aforementioned issues or multi-modality of the objective function, the computational cost of the EM-driven design increases tremendously. This paper introduces a frequency-related regularization as a way of improving the efficacy of simulation-based design processes. Regularization is realized by enhancing the conventional (e.g., minimax) objective function using a dedicated penalty term that fosters the alignment of the circuit characteristics (e.g., the operating frequency or bandwidth) with the target values specified by the design requirement. This leads to smoothening of the objective function landscape, improves reliability of the optimization process, and reduces its computational cost as compared to the standard formulation. An added benefit is the increased immunity to poor initial designs and multi-modality issues. In particular, regularization can make local search routines sufficient in situations where global optimization would normally be necessary. The presented approach is validated using two miniaturized circuits, a rat-race and a branch line coupler. The numerical results demonstrate its superiority over conventional design problem formulations in terms of reliability of the optimization process. INDEX TERMS Microwave design; miniaturized passive components; design optimization; EM-driven design; gradient-based search; regularization.

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Nonlinear Mutual Coupling Compensation Operator Design Using a Novel Electromagnetic Machine Learning Paradigm

Cited by 62 publications

References 16 publications

The antenna spacetime system theory of wireless communications

The antenna spacetime system theory of wireless communications

Antenna Modeling Using Variable-Fidelity EM Simulations and Constrained Co-Kriging

Improved-Efficacy Optimization of Compact Microwave Passives by Means of Frequency-Related Regularization

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