Speed up of near-field physical optics scattering calculations by use of the sampling theorem

Cramer, P. W.; Imbriale, W.

doi:10.1109/20.312607

Cited by 4 publications

(3 citation statements)

References 2 publications

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“…The iterative physical optics (IPO) technique has been studied for the analysis of open-ended cavities based on the recursive application of the PO integral in order to take into account the multiple reflections inside the cavity [ 43 , 44 , 45 ]. Several additional numerical techniques and tools with the purpose of speeding up the analysis and synthesis of reflector antennas can be found in the literature [ 46 , 47 , 48 , 49 ].…”

Section: Numerical Techniques For the Analysis Of Reflector Antennasmentioning

confidence: 99%

HERAS: A Modular Matlab Tool Using Physical Optics for the Analysis of Reflector Antennas

Baldominos

Mercader-Pellicer

Goussetis

et al. 2023

Sensors

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HERAS is a tool developed in Matlab for the analysis of reflector antennas using physical optics (PO) theory. Its graphical user interface (GUI) and source code are freely available for educational and research purposes. It has the necessity of being a flexible tool to provide adaptability to system engineering requirements and can also be of interest to antenna engineers working on the design of reflector antennas. Due to the increasing demand of broadband services, satellite communications systems are becoming highly complex in order to meet connectivity requirements. To fully exploit the benefits of these systems, multidimensional optimisations are crucial, which call for an efficient estimation of the coverage characteristics. Reflector-based solutions are one of the preferred architectures for very high-throughput satellite (VHTS) systems. A detailed description of HERAS is presented in this paper which has been validated with available commercial software packages. In addition, some examples are described in which the tool has been used for the efficient estimation of VHTS systems performance.

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Section: Numerical Techniques For the Analysis Of Reflector Antennasmentioning

confidence: 99%

HERAS: A Modular Matlab Tool Using Physical Optics for the Analysis of Reflector Antennas

Baldominos

Mercader-Pellicer

Goussetis

et al. 2023

Sensors

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“…The image theorems have been frequently used as approximate solutions for Love's equivalence theorem in diffraction and radiation phenomena [14], [15], [16]. There are also many scattering problems, where the induction theorem and Physical Optics (PO) approximation have been extensively adopted in evaluations of Radar Cross Section (RCS) [17], [18], [19], [20], [21]. Recently, image theorems also find their applications in mirror system designs for high-power quasi-optical gyrotrons [1]- [6], [10].…”

Section: Chapter 4 the Validity Of Image Theoremsmentioning

confidence: 99%

Millimeter-wave Techniques: Theory, Algorithms and Methods

Liao¹

2020

Preprint

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The goal of book is to present the theory, algorithms and methods to design the millimeter-wave Gyrotron beam-shaping antenna system (of good metal conductor, e.g., of aluminum or copper) to shape four roughly Gaussian beams of different frequencies into one specified high-quality Gaussian beam at the output of the mirror system. The input beams are from a quasi-optical launcher which converts each of the following mode/frequency pairs into a roughly Gaussian form: TE21,6 (107.5 GHz), TE22,6 (110.0 GHz), TE24,7 (124.5 GHz) and TE25,7 (127.5 GHz). Each of the output beams from the launcher is to be converted into a Gaussian beam with specified waist radius and with as high a coupling coefficient as possible to an ideal Gaussian beam. A design optimization procedure for the mirror system is developed and applied to the case of the four mode/frequency pairs above. The frequencies are specified because they are of interest to General Atomics. The 127.5 GHz frequency is the ITER start-up frequency. In addition, the design obtained is tested by simulation for two other mode/frequency pairs, TE23,6 (112.9 GHz) and TE23,7 (121.5 GHz). The theory, algorithms and methods required in such multi-mode beam-shaping mirror system designs are investigated. These include (1) the iterative phase retrieval technique for phase retrieval from measured magnitude-only data; (2) a theoretical formula developed to evaluate the validity of the image theorem approximation in the cylindrical geometry used during the mirror system design; (3) the Taylor-FFT algorithm developed in this research work for fast computation of the electromagnetic wave propagation and scattering; (4) the newly developed phase gradient phase correction method for mirror surface correction; and (5) the least mean square optimization method, proposed for multi-mode mirror design. Based on our theory, algorithms and methods, a coupling coefficient to the target Gaussian beam greater than 99.99% is achieved for the single-mode designs and an average coupling coefficient up to 99.50% within the window aperture of 88 mm diameter for the multi-mode design. The design has been successfully verified the Method of Moments software Surf3D.

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“…The image approximation has been frequently used as the approximate solution of Love's equivalence principle for the electromagnetic wave propagation [1][2][3] and in the induction equivalent and the physical equivalent in the electromagnetic wave scattering phenomenon, which includes microwave imaging [4,5], reflector antenna design [6,7], evaluation of Radar Cross Section (RCS) [8,9] and other applications [10][11][12]. Recently, the image approximation also finds the application in the mirror system design for quasi-optical mode converters in high-power gyrotrons [13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

On the Image Approximation for Electromagnetic Wave Propagation and Pec Scattering in Cylindrical Harmonics

Liao¹,

Vernon²

2006

PIER

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Abstract-A closed-form formula, the discrepancy parameter, which has been defined as the ratio of the modal expansion coefficients between the electromagnetic field obtained from the image approximation and the incident electromagnetic field, has been proposed for the evaluation of the validity of the image approximation in the electromagnetic wave propagation, i.e., Love's equivalence principle, and the electromagnetic wave scattering, i.e., the induction equivalent and the physical equivalent, in the cylindrical geometry. The discrepancy parameter is derived through two equivalent methods, i.e., the vector potential method through the cylindrical addition theorem and the dyadic Green's function method, for both the TE and TM cylindrical harmonics. The discrepancy parameter justifies the fact that the image approximation approaches the exact solution for the cylindrical surface of infinite radius. For the narrow-band field with limited spectral component in k space, the cylindrical modal expansion of the electromagnetic wave into the TE and TM cylindrical harmonics can be separated into the forward-propagating wave that propagates forward and the back-scattered wave that is back-scattered by the PEC surface, within the image approximation. The discrepancy parameter shows that the validity of the image approximation depends on the property of the incident field and the radius of the cylindrical surface, i.e., the narrow-band field and the surface of a large radius are in favor of the image approximation, which has also been confirmed by the numerical result. Liao and Vernon

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Speed up of near-field physical optics scattering calculations by use of the sampling theorem

Cited by 4 publications

References 2 publications

HERAS: A Modular Matlab Tool Using Physical Optics for the Analysis of Reflector Antennas

HERAS: A Modular Matlab Tool Using Physical Optics for the Analysis of Reflector Antennas

Millimeter-wave Techniques: Theory, Algorithms and Methods

On the Image Approximation for Electromagnetic Wave Propagation and Pec Scattering in Cylindrical Harmonics

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