A fast near-to-far-field transformation in body of revolution finite-difference time-domain method

Farahat, N.; Yu, Weikuan; Mittra, R.

doi:10.1109/tap.2003.816360

Cited by 6 publications

(4 citation statements)

References 5 publications

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“…The excitation is introduced in a cross-section, by setting the corresponding components of the fields to vary in time as a modulated Gaussian pulse [27]. A fast near-to-far-field transformation method proposed in [28] is used.…”

Section: The Body Of Revolution Finite-difference Time-domainmentioning

confidence: 99%

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The Fine-Grained Parallel Micro-Genetic Algorithm and Its Application to Broadband Conical Corrugated-Horn Antenna

Chang¹,

Zhou²,

Chen³

et al. 2013

PIER

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Abstract-The fine-grained parallel micro-genetic algorithm (FGP-MGA) is developed to solve antenna design problems. The synthesis of uniformly exited unequally spaced array is presented. Comparison with the micro-genetic algorithm (MGA) has been carried out. It is seen that the FGPMGA significantly outperforms MGA, in terms of both the convergence rate and exploration ability. The FGPMGA can also reduce the optimization time. Then the FGPMGA and the body of revolution finite-difference time-domain (BOR-FDTD) are combined to achieve an automated design process for conical corrugated-horn antenna. Numerical simulation results show that the horn antenna has good impedance matching (the VSWR is less than 1.5), stable beamwidth and gain, as well as good rotation symmetry patterns over the whole band 8∼13 GHz.

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Section: The Body Of Revolution Finite-difference Time-domainmentioning

confidence: 99%

“…The BOR-FDTD employs a 2D solution problem instead of a full 3D one due to the axial symmetric property and saves computational resources [26][27][28]. This method is a robust and versatile numerical tool for solving axial symmetric problems.…”

Section: Introductionmentioning

confidence: 99%

The Fine-Grained Parallel Micro-Genetic Algorithm and Its Application to Broadband Conical Corrugated-Horn Antenna

Chang¹,

Zhou²,

Chen³

et al. 2013

PIER

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“…where S is the enclosing cylindrical surface (virtual). It can be shown that for a BOR structure, we can use a technique similar to the one described in [5], and simplify the surface integrals defined in Eqs. (9a) through (9d) by replacing them with line integrals with respect to lines L 1 , L 2 , and L 3 .…”

Section: Bor Near-to-far Field Transformationmentioning

confidence: 99%

“…Depending on the geometry of the problem, we can either use a perfect electric conductor (PEC) or an anisotropic perfectly matched layer (APML) for mesh truncation, and analyze both the boxed and open guided-wave microwave structures [4]. To compute the far fields, we use a near-to-far-field transformation, adapted to the BOR, for efficient calculation of radiation fields based on line integrals along the line contour of equivalent electric and magnetic currents, as opposed to surface integrals that are more costly to compute [5]. To analyze arbitrary BOR geometries, we have developed a mesh generator in conjunction with the commercial geometrical design tool AutoCAD, to systematically create geometry and material input files for the BOR/FDTD solver.…”

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confidence: 99%

Hybrid FDTD/AUTOCAD® method for the analysis of BOR horns and reflectors

Yang

Chen

et al. 2003

Micro & Optical Tech Letters

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RESULTSAs an example, an antenna aperture on ground plane, 1.5 ϫ 1.5 in size, has been considered. The aperture distribution is given by Eq. (7), where E o ϭ 0.5 V/m and a ϭ b ϭ 1.5. The tangential components of the near-field samples taken as reference by the GA were computed at a planar grid S f 10 ϫ 10 in size, located 4 away from the antenna aperture and with a /4 uniform spacing. An equivalent model made up of 98 dipoles with a /4 spacing has been considered for S e . For the binary GA, the 196 unknowns of the chromosome have been coded using 9 bits per parameter, with an initial population of 4500 individuals to ensure diversity.Fitness evolution is shown in Figure 2 and the far-field patterns reconstructed with this approach and with the classical FFT-based method are compared with theoretical results in Figure 3 for the ϭ 0°cut. For the FFT case, a planar grid made up of 126 ϫ 126 near-field samples, /5 spaced on a 25 ϫ 25 plane located 4 away from the source has been considered and a 128 ϫ 128 FFT processing has been performed. A 3D far-field pattern analysis showed a maximum error of up to 1.5 dB (1.8 dB) for ϭ Ϯ45°o r 4.6 dB (11 dB) for ϭ Ϯ60°, for the GA (FFT) case. It should be noted that the level of the electric field is already 26 dB below the maximum for ϭ Ϯ60°. Clearly, GAs provide better results than FFT using a smaller scanning area. However, the elapsed CPU time is far higher. CONCLUSIONSA useful method for predicting the radiation pattern of an antenna from planar near-field samples has been presented. The method reconstructs the source radiation pattern using an equivalent model optimized by means of a genetic-algorithm-based process. The method is appropriate for small-and medium-size antennas, showing a better performance than the classical FFT-based method. For large antennas, the complexity of the equivalent model drastically slows down the optimization process. ACKNOWLEDGMENTSThis work was partly supported by CICYT/FEDER projects 1FD97-0594-C03-02/ TIC and 1FD1997-1975 [4]. To compute the far fields, we use a near-to-far-field transformation, adapted to the BOR, for efficient calculation of radiation fields based on line integrals along the line contour of equivalent electric and magnetic currents, as opposed to surface integrals that are more costly to compute [5]. To analyze arbitrary BOR geometries, we have developed a mesh generator in conjunction with the commercial geometrical design tool AutoCAD, to systematically create geometry and material input files for the BOR/FDTD solver. We have validated the technique for a number of BOR horns and reflector antennas and have achieved excellent agreement between the numerical results derived in this work and those available in the literature for all of the cases investigated. BOR/FDTD ALGORITHMOur objective is to solve the Maxwell's equations for BOR geometries in the cylindrical coordinate system that read as follows:In view of the azimuthal symmetry, we can represent the electromagnetic fields as infinite Fourier series expansions:wh...

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Selected Applications in Waveguide Systems

Kantartzis

Tsiboukis

2006

Higher Order FDTD Schemes for Waveguide and Antenna Structures

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A fast near-to-far-field transformation in body of revolution finite-difference time-domain method

Cited by 6 publications

References 5 publications

The Fine-Grained Parallel Micro-Genetic Algorithm and Its Application to Broadband Conical Corrugated-Horn Antenna

The Fine-Grained Parallel Micro-Genetic Algorithm and Its Application to Broadband Conical Corrugated-Horn Antenna

Hybrid FDTD/AUTOCAD® method for the analysis of BOR horns and reflectors

Selected Applications in Waveguide Systems

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