Efficient evaluation of antenna fields by a time-domain multipole analysis

Adam, Jost; Klinkenbusch, L.

doi:10.5194/ars-7-43-2009

Cited by 6 publications

(5 citation statements)

References 12 publications

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“…Therefore, the frequency-domain NF-FF allow us to calculate the radiation pattern of a broadband antenna for a large frequency band. Also it is an alternative technique to obtain the frequency-domain radiation pattern for broadband antennas without the need to perform costly timedomain numerical computation [9], [10].…”

Section: Characterization Of the Radiation Pattern Of Antennas Via Fdmentioning

confidence: 99%

Characterization of the radiation pattern of antennas via FDTD and time-domain moment expansion

Ramos

Rego

2014

J. Microw. Optoelectron. Electromagn. Appl.

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An alternative method is proposed to characterize the radiation pattern of antennas from an impulse response, based on a moment expansion together with a frequency domain near-to-farfield transformation via a FDTD/CPML solver. The approach introduced in the present work is intended for printed antenna analysis in special cases when the geometries to be modeled require a high degree of discretization in the space-time domain, which directly affects the frequency resolution when using FFT to perform the conventional NF-FF techniques. Results are compared with those obtained by a reference frequency-domain NF-FF technique and the applicability of the proposed method is demonstrated. isA deconvolution with less computational effort can be obtained using the expansion as in [14]

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Section: Characterization Of the Radiation Pattern Of Antennas Via Fdmentioning

confidence: 99%

Characterization of the radiation pattern of antennas via FDTD and time-domain moment expansion

Ramos

Rego

2014

J. Microw. Optoelectron. Electromagn. Appl.

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“…For frequency-domain radiation patterns, applying a modified Fourier transform to the time-domain multipole amplitudes, the multipole amplitudes are obtained in frequency-domain and the power radiation pattern of the antenna can be obtained by [9]…”

Section: Time-domain Spherical-multipole Near-to-far-field Expansionmentioning

confidence: 99%

“…, where n may be in the range [8][9][10],  is the largest FDTD cell size and f M is the highest frequency to be computed. The Gaussian-pulse parameters may be also such that its 10% amplitude upper frequency f G may be in the range max 1.5 , FDTD M ff   [13].…”

Section: Moment Expansion Of Time Functions and Impulse Responsementioning

confidence: 99%

Characterization of the radiation pattern of antennas using time-domain spherical-multipole and moment expansion

Ramos

Rego

Fonseca

2013

J. Microw. Optoelectron. Electromagn. Appl.

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This paper presents results of a time-domain spherical-multipole near-to-far-field transformation together with a moment expansion applied to antenna radiation patterns. The equivalence principle is applied to the tangential fields all over the FDTD/WP-PML spatial grid and the use of the spherical-multipole expansion leads to the near-to-far-field transformation, and energy and power norms of temporal signals are used to obtain the antenna radiation patterns for transient and steady-state responses. Such approach is employed to obtain UWB antenna radiated fields and radiation patterns directly in time-domain, it being more convenient to perform an unified characterization in time and frequency domains. Index Terms-Finite-difference time-domain method, time-domain spherical multipole, time-domain moment expansion. I. INTRODUCTION The finite-difference time-domain (FDTD) method in addition to absorbing boundary conditions and perfect matched layers (PML) has been successfully used in analysis of radiation and scattering problems. FDTD is very efficient when making near-field calculations, while for the far field it is necessary to implement an additional method to perform a near-to-far-field (NF-FF) transformation. The first technique used to perform the NF-FF transformation could only be applied for a single frequency analysis [1], [2]. In order to obtain a larger frequency bandwidth response, a broadband excitation followed by discrete Fourier transform was performed [1], [3]. Recently, methods involving a recursive addition of tangential fields contribution over a virtual equivalence surface have been used to perform the same task [4]-[7]. Conventional time-domain NF-FF transformation techniques [1], [3], where time-domain far fields can be directly obtained, are based on the retarded potential method and as a consequence, a new integration over the near-field is necessary for each observation point [5], [9]. Therefore, when broadband results are required at a large number of observation angles, as is the case with radiation patterns, these techniques require a large number of computational resources [3]. Recently a time-domain spherical-multipole near-to-far

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“…In order to determine the timedomain spherical-multipole amplitudes and from the tangential field on , the spherical-multipole interface [17] is employed, where the tangential field components on the discretized surface are replaced by each finite numbers of electric and magnetic elementary dipoles, located on the Huygens surface at equidistant points. As shown in [7], [8], the time-domain spherical-multipole amplitudes and at discrete time steps are then calculated by a suitable procedure incorporated into and running concurrently to the FDTD time-stepping algorithm.…”

Section: Time-domain Spherical-multipole Based Near-field-to-far-mentioning

confidence: 99%

Numerical Multipole Analysis of Ultrawideband Antennas

Adam

Klinkenbusch

Mextorf

et al. 2010

IEEE Trans. Antennas Propagat.

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A recently introduced systematic approach to efficiently obtain the time-domain electromagnetic field of an arbitrary antenna radiating into the free space is applied to numerically analyze the frequency-domain features of an ultrawideband antenna. In a first stage, the finite-difference time-domain method is employed to obtain the time-domain spherical-multipole amplitudes for the antenna which is driven by a wide-band signal. This time-domain representation is valid in the far field only, but a single numerically performed Fourier transform leads to the frequency-domain spherical-multipole amplitudes valid for the entire spectrum of the input impulse and at any point outside a minimum sphere containing all radiating elements. The approach is applied to an antipodal Vivaldi antenna to obtain three dimensional radiation patterns which are compared to experimental results as well as to the outcomes of other numerical schemes. Moreover, a total scattering error is defined and numerically evaluated to estimate the overall accuracy of the proposed method.Index Terms-Antenna radiation patterns, error analysis, finite-difference time-domain (FDTD) methods, near-field far-field transformations, ultrawideband antennas, Vivaldi antennas.

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Efficient evaluation of antenna fields by a time-domain multipole analysis

Cited by 6 publications

References 12 publications

Characterization of the radiation pattern of antennas via FDTD and time-domain moment expansion

Characterization of the radiation pattern of antennas via FDTD and time-domain moment expansion

Characterization of the radiation pattern of antennas using time-domain spherical-multipole and moment expansion

Numerical Multipole Analysis of Ultrawideband Antennas

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