A new termination condition for the application of FDTD techniques to discontinuity problems in close homogeneous waveguide

Moglie, Franco; Rozzi, T.; Marcozzi, P.; Schiavoni, A.

doi:10.1109/75.173399

Cited by 49 publications

(16 citation statements)

References 7 publications

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“…This paper presents a new approach to construct multimodal waveguide port boundary termination conditions for time-domain computations employing statespace models (SSMs). The presented method is based on the transform of the well-known characteristic admittances of port modes in frequency domain to time domain, as it is proposed in [4] and [5]. However, in contrast to [4] and [5], the presented modal absorbing boundary condition (MABC) does not require to evaluate convolution integrals involving Bessel functions.…”

Section: Introductionmentioning

confidence: 96%

“…The presented method is based on the transform of the well-known characteristic admittances of port modes in frequency domain to time domain, as it is proposed in [4] and [5]. However, in contrast to [4] and [5], the presented modal absorbing boundary condition (MABC) does not require to evaluate convolution integrals involving Bessel functions. Instead, the convolution operations are approximated by suitable SSMs, whose system responses are conveniently computable by means of standard integration schemes.…”

Section: Introductionmentioning

confidence: 96%

“…1(a)] to be infinitely long such that there is no reflection from ∂ wg . The modal characteristic wave impedances and admittances are different for TE and TM port modes (see [4], [5], and [7])…”

Section: Introductionmentioning

confidence: 99%

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Time-Domain Absorbing Boundary Terminations for Waveguide Ports Based on State-Space Models

2014

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Absorbing boundary conditions for waveguide ports in time domain are important elements of transient approaches to treat RF structures. A successful way to implement these termination conditions is the decomposition of the transient fields in the absorbing plane in terms of modal field patterns. The absorbing condition is then accomplished by transferring the wave impedances (or admittances) of the modes to time domain, which leads to convolution operations involving Bessel functions and integrals of Bessel functions. This paper presents a new alternative approach: the convolution operations are approximated by appropriate state-space models whose system responses can be conveniently computed by standard integration schemes. These schemes are indispensable for transient simulations anyhow. Sufficiently far away from the cutoff frequency, a wideband match is achieved.Index Terms-Modal analysis, modal wave absorption, time-domain analysis, waveguide boundary condition.

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Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 96%

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Time-Domain Absorbing Boundary Terminations for Waveguide Ports Based on State-Space Models

2014

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“…In the analogous FDTD approach [14], the fields are decomposed into incident and reflected wave amplitudes ("TLM" approach) and the characteristic impedance is used for the calculation of the reflected wave amplitudes. A similar absorber based on a circuit (voltage-current) approach has been proposed by Moglie et al [15]. Due to the field decomposition, both of these approaches are characterized 0018-9480/98$10.00 © 1998 IEEE by higher memory and execution time requirements than the conventional FDTD absorbers.…”

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confidence: 99%

FDTD characterization of waveguide-probe structures

Tentzeris

Krumpholz

Dib³

et al. 1998

IEEE Trans. Microwave Theory Techn.

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Abstract-The finite-difference time-domain (FDTD) techniqueis applied in the calculation of the S-parameters of diode mounting and waveguide-probe structures. The influence of the critical geometrical design parameters on the coupling of the coplanar feedline probe to the waveguide is investigated. A waveguide absorber based on analytic Green's functions is used to minimize the reflections over a wide band of frequencies.

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“…For a 3D structure, such a simulation is often inefficient because the simulation is executed in three dimensions and therefore requires large memory and CPU time. In order to solve the problems as well as to develop efficient absorbing boundary conditions, many 1D modal absorbing boundary conditions (modal ABCs) have been proposed [4][5][6][7][8][9][10][11][12][13][14]. Most of them use analytically or numerically generated Green's functions or impedance functions.…”

Section: Introductionmentioning

confidence: 99%

An Efficient Modal FDTD for Absorbing Boundary Conditions and Incident Wave Generator in Waveguide Structures

Luo¹,

Chen²

2007

PIER

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Abstract-When the finite-difference time-domain method is used to compute waveguide structures, incident waves are needed for calculating electrical parameters (e.g., the scattering parameters), and effective absorbing boundary conditions are required for terminating open waveguide structures. The incident waves are conventionally obtained with inefficient three-dimensional (3D) simulations of long uniform structures, while the absorbing boundary conditions reported so far do not perform well at or below cut-off frequencies. To address the problems, we propose a novel one-dimensional (1D) finitedifference time-domain method in this paper. Unlike the other methods developed so far, the proposed method is derived from the finite-difference time-domain formulation, and therefore has the same numerical characteristics as that of the finite-difference time-domain method. As a result, when used to obtain an incident wave, it produces results almost identical to those produced by the conventional finitedifference time-domain method except computer rounding-off errors. When used as the absorbing boundary condition, it produces reflections of less than −200 dB in entire frequency spectrum including the cut-off frequencies.

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A new termination condition for the application of FDTD techniques to discontinuity problems in close homogeneous waveguide

Cited by 49 publications

References 7 publications

Time-Domain Absorbing Boundary Terminations for Waveguide Ports Based on State-Space Models

Time-Domain Absorbing Boundary Terminations for Waveguide Ports Based on State-Space Models

FDTD characterization of waveguide-probe structures

An Efficient Modal FDTD for Absorbing Boundary Conditions and Incident Wave Generator in Waveguide Structures

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