scholarly journals Retrieving the Effective Parameters of an Electromagnetic Metamaterial using the Nicolson-Ross-Weir method: an Analytic Continuation Problem along the Path Determined by Scattering Parameters

IEEE Access ◽  
2021 ◽  
pp. 1-1
Author(s):  
Giovanni Angiulli ◽  
Mario Versaci
2021 ◽  
Vol 0 (0) ◽  
pp. 0
Author(s):  
Xuping Xie ◽  
Feng Bao ◽  
Thomas Maier ◽  
Clayton Webster

<p style='text-indent:20px;'>We propose a data-driven learning framework for the analytic continuation problem in numerical quantum many-body physics. Designing an accurate and efficient framework for the analytic continuation of imaginary time using computational data is a grand challenge that has hindered meaningful links with experimental data. The standard Maximum Entropy (MaxEnt)-based method is limited by the quality of the computational data and the availability of prior information. Also, the MaxEnt is not able to solve the inversion problem under high level of noise in the data. Here we introduce a novel learning model for the analytic continuation problem using a Adams-Bashforth residual neural network (AB-ResNet). The advantage of this deep learning network is that it is model independent and, therefore, does not require prior information concerning the quantity of interest given by the spectral function. More importantly, the ResNet-based model achieves higher accuracy than MaxEnt for data with higher level of noise. Finally, numerical examples show that the developed AB-ResNet is able to recover the spectral function with accuracy comparable to MaxEnt where the noise level is relatively small.</p>


Mathematics ◽  
2021 ◽  
Vol 9 (18) ◽  
pp. 2255
Author(s):  
Xuemin Xue ◽  
Xiangtuan Xiong

In this paper, the numerical analytic continuation problem is addressed and a fractional Tikhonov regularization method is proposed. The fractional Tikhonov regularization not only overcomes the difficulty of analyzing the ill-posedness of the continuation problem but also obtains a more accurate numerical result for the discontinuity of solution. This article mainly discusses the a posteriori parameter selection rules of the fractional Tikhonov regularization method, and an error estimate is given. Furthermore, numerical results show that the proposed method works effectively.


2019 ◽  
Vol 397 ◽  
pp. 187-199
Author(s):  
Saida Mellal ◽  
Toufik Ziar ◽  
Hichem Farh ◽  
Khalid Hati ◽  
Badreddine Zemmal ◽  
...  

We propose here a method witch analyze the behavior of Quasi-square open ring frequency selective surface (FSS) by using an approach based on the wave iterative concept procedure method (WCIP) coupled to Retrieval from Scattering Parameters method . The scattering parameters calculated by WCIP for a Quasi-square open ring FSS are used, in analytical formulas, to calculate directly observable effective constitutive parameters (relative electric permittivity εreff , magnetic permeability μreff and refractive index n ) of a frequency selective surface. Results of effective constitutive parameters for a Quasi-square open ring FSS structure are presented by Simulation using MATLAB program codes translating the implementation of the proposed approach.


2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Guizhen Lu ◽  
Zhonghang Duan ◽  
Hongcheng Yin ◽  
Zhihe Xiao ◽  
Jing Zhang

The electromagnetic parameters of the dispersion material and metamaterial are vital in the engineering. The phase unwrapping method is proposed to deal with the phase ambiguity of the transmission and reflection method in electromagnetic (EM) parameters extraction. The computed results demonstrate that the proposed method can give the correct effective parameters. In dealing with scattering parameters with noise, the wavelet transform method is utilized to remove the noise added to the scattering parameters. The simulated results show that the correct material parameters can be obtained by wavelet denoising method. Finally, the proposed method is used to extract the parameters of the photonic crystal. The effective parameter gives a different aspect in explanation to the function for the photonic crystal.


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