Analysis of Transient Electromagnetic Scattering Using Time Domain Fast Dipole Method

Ding, Jian-Jiun; Gu, Chang Qing; Li, Zhuo; Niu, Zhenyi

doi:10.2528/pier12121104

Cited by 12 publications

(4 citation statements)

References 22 publications

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“…As a result, a defect waveguide should be replaced with a new one [12][13][14][15][16]. This also includes classical open waveguides [17][18][19][20][21]. The possibility of supporting one-way states by a closed waveguide has not been widely investigated so far.…”

Section: Introductionmentioning

confidence: 99%

Super ultra-wideband closed waveguide supporting one-way states

Ahmadi¹,

Zafari²,

Pasdari-Kia³

et al. 2023

Preprint

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<p>In this work, we propose a pseudospin-polarized closed waveguide whose walls are formed by dual electromagnetic boundary conditions. The structure has a very wide bandwidth so that it covers an extremely wide electromagnetic spectrum. The proposed waveguide supports one-way pseudospin states resulting from the establishment of dual relationships at the waveguide boundaries, and hence the establishment of mirror reflection symmetry. This provides the proposed waveguide with the ability to suppress backscattering. The boundary conditions of the proposed structure consist of complementary metasurfaces which have dual surface impedances. The presence of these boundary conditions leads to forming a pseudospin-polarized waveguide having the ability to suppress and filter the backward modes that may be excited along bent paths or discontinuities. To the best of our knowledge, this is the widest bandwidth waveguide that has been proposed so far, so that the isolation of the waveguide in the frequency range of 7- 350 GHz is above -0.5 dB. In addition, we use a very precise method based on the variational method to calculate the surface impedance of the metasurfaces forming the waveguide boundaries so as to increase the accuracy of the obtained results.</p>

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Section: Introductionmentioning

confidence: 99%

Super ultra-wideband closed waveguide supporting one-way states

Ahmadi¹,

Zafari²,

Pasdari-Kia³

et al. 2023

Preprint

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“…Only the PWTD [12,13] and the IFMM are not the accelerating methods to solve the IEs for electromagnetics. The other methods include the hierarchical FFT algorithm (HIL-FFT) [25], the time-domain adaptive integral method (TD-AIM) [26], the two-level nonuniform grid time domain (NGTD) algorithm [27] and its multi-level algorithm [18], the time-domain UV method [28], the fast dipole method [29], and potentially the accelerated Cartesian expansions (ACE) for evaluating general pairwise interactions [30,31]. The methodological and highest similarity of the proposed IFMM to ACE [30] is to utilise the Taylor expansion fundamentally when both methods formulate their FMMs; precisely speaking, the proposed method exploits an interpolation of the kernel function to realise its separation of variables and then the Taylor expansion to construct a fast M2L operation, which is described in Algorithm 4 in [24].…”

Section: Introductionmentioning

confidence: 99%

A fast time-domain boundary element method for three-dimensional electromagnetic scattering problems

Takahashi

2023

Preprint

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This paper proposes a fast time-domain boundary element method (TDBEM) to solve three-dimensional transient electromagnetic scattering problems regarding perfectly electric conductors in the classical marching-on-in-time manner. The algorithm of the fast TDBEM is a time-domain variant of the interpolation-based fast multipole method (IFMM), which is similar to the time-domain IFMM for acoustic scattering problems investigated in the author's previous studies. The principle of the present IFMM is to interpolate the kernel functions of the electric and magnetic field integral equations (EFIE and MFIE, respectively) so that every kernel function is expressed in a form of separation of variables in terms of both the spatial and temporal variables. Such an expression enables to construct a fast method to evaluate the scalar and vector potentials in the EFIE and MFIE with using so-called multipolemoments and local-coefficients associated with a space-time hierarchy. As opposed to O(N 2 s N t ) of the conventional TDBEM, the computational complexity of the fast TDBEM is estimated as O(N 1+δ s N t ), where N s and N t stand for the spatial and temporal degrees of freedom, respectively, and δ is typically 1/2 or 1/3. The numerical examples presented the advantages of the proposed fast TDBEM over the conventional TDBEM when solving large-scale problems.

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“…In addition, the TDIE formulations suffer from great difficulties for electrically large objects, due to the need of using fast algorithms to solve TDIEs. In the past decades, many fast algorithms such as time domain fast dipole method (TD-FDM) [8], multilevel time domain fast dipole method [9] and the hybrid of TDIE and time domain physical optics (TDPO) methods [10] have been introduced to reduce the memory requirement and computational complexity of the MOT scheme. A wise solution to significantly enhance the extent of the stable region, reduce numerical errors and increase the efficiency is to use analytical time derivatives and time convolution integrals arising in the TDIEs [11,12].…”

Section: Introductionmentioning

confidence: 99%

Survey of Temporal Basis Functions for Transient Scattering by Conducting Cylinders Using Td-Efie Formulation-Te Case

Azari¹,

Firouzeh²,

Zeidaabadi-Nezhad³

2014

PIER M

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Abstract-In this paper, different causal sub-domain temporal basis functions are investigated to make the explicit marching-on-in time schemes converge and stable for solving two dimensional time domain EFIE. PEC cylinders with arbitrary cross section are illuminated by a TE-polarized Gaussian plane wave. Two different approximations are used for calculation of the singular elements of the impedance matrix analytically. In the Time Domain Method of Moment (TD-MoM) formulation of the Electric Field Integral Equation (EFIE) of the problem, the free-space two-dimensional Green's function and triangular spatial basis function are used. By employing Galerkin's method in spatial domain and point matching in time domain, all time convolution integrals and self-terms are evaluated analytically to increase the accuracy and stability of the proposed technique. The stability and efficiency of the new technique are confirmed by comparison with literature.

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Analysis of Transient Electromagnetic Scattering Using Time Domain Fast Dipole Method

Abstract: Numerical results about the electromagnetic scattering from perfect electric conductor (PEC) objects are given to demonstrate the validity and efficiency of the proposed scheme.

Cited by 12 publications

References 22 publications

Super ultra-wideband closed waveguide supporting one-way states

Super ultra-wideband closed waveguide supporting one-way states

A fast time-domain boundary element method for three-dimensional electromagnetic scattering problems

Survey of Temporal Basis Functions for Transient Scattering by Conducting Cylinders Using Td-Efie Formulation-Te Case

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