1,721,306 research outputs found
GPU Computing in Reflectarray Synthesis
No full textA multistage synthesis approach for the design of aperiodic refiectarray, based on an effective and efficient implementation on GPU is presented. The pattern evaluation is accelerated thank to the use of the nonuniform fast Fourier transform routines. Furthermore a particle swarm optimizer, implemented on GPU, is exploited in the first stage of the synthesi
Radiation from aperiodic reflectarrays using optimized NUFFTs
No full textWe deal with one of the computationally most critical steps of the Phase-Only synthesis of aperiodic reflectarrays, namely, the fast evaluation of the radiation operator. We present an approach exploiting the use of a fast numerical algorithm using 2D Non-Uniform FFTs (NUFFTs) of NED (Non-Equispaced Data) type and of parallel processing on Graphics Processing Units (GPUs). A fast GPU-implementation of the NUFFT routine is achieved by exploiting a polynomial representation of the spatial and spectral windows and using the Horner polynomial calculation scheme.Numerical result highlight the performance of the developed approach
SVO and Singular Functions Quadrature in Near-Field Antenna Measurements
No full textWe show that the sampling approach provided by the Singular Value Optimization (SVO) technique defines quadrature rules of the singular functions arising from the application of the Singular Value Decomposition (SVD) approach. In other words, by the information collected by the elementary antennas defined by the SVO, it is possible to accurately determine the open circuit voltages received by the 'virtual' antennas defined by the singular functions.The discussion is led in a 2D, scalar setting. The theoretical arguments are supported by numerical results referring to a full 3D Near-Field/Far-Field (NFFF) transformation problem
Gradient-based near-field antenna characterization in planar geometry
No full textA near field characterization technique, based on the optimization of the Singular Value Behavior, is here accelerated by using the analytical expression of the gradient of the relevant objective functional. This solution allows to conveniently tackle the cases of electrically large antennas
Optimized NUFFT for 2D array antenna radiation
No full textWe propose an optimized approach for implementing Non-Uniform Fast Fourier Transform (NUFFT) algorithms under a general and new perspective for two-dimensional transformations. A case study of electromagnetic interest is carried out by applying the developed NUFFT to the radiation of a planar irregular array antenna onto a set of regular spectral points
Flexible set-up of measurement configurations in inverse scattering by SVO
No full textWe show that the Singular Value Optimization (SVO) approach can also be used in linear inverse scattering under the Born approximation in a very flexible, efficient and effective way. In particular, we numerically highlight that SVO is able to manage different measurement configurations, in particular multimonostatic, multistatic/single-view and multistatic/multi-view configurations, while properly taking into account the shape and size of both the investigation and measurement domains as well as "partial" acquisitions due to aspect limitations of the data. We also show numerically how SVO is able to determine the frequency sampling, however in the simplified hypothesis of uniform frequency step to keep the computational burden of the optimization low
Dimensioning Flat Equivalent Radiators
Full text linkWe deal with the problem of modeling a radiator/scatterer using an equivalent radiator. The problem amounts at determining shape and size of a radiating surface D′ producing, on a region D , an electromagnetic field close to that generated by the primary radiator/scatterer. For a fixed equivalent radiator’s shape, we deal here with the dimensioning issue only. The approach exploits the singular value decomposition (SVD) of the operators relating the radiator/scatterer to the field on D and the equivalent panel to the field on D . The size of the equivalent radiator is determined by minimizing the error between the primary radiated/scattered field and that radiated using D′ . The error is expressed as a Hermitian, positive semidefinite quadratic form: the dimensioning problem thus consists of determining the size of the equivalent radiator maximizing its minimum eigenvalue. The maximization is performed by choosing the size value leading to an error dropping below a prescribed maximum tolerated threshold. We present numerical test cases for a planar radiator with rectangular shape
An SVO-based approach for electromagnetic inverse scattering
No full textWe present an approach based on the Born approximation and on the Singular Value optimization (SVO) technique to extract information on scatterers in inverse problems. A 2D geometry with multi-frequency/single-view plane wave illumination and TM polarization with near-field acquisitions is considered. Numerical results show that it is possible to significantly reduce the number of near-field samples against the canonical λmin/2 criterion
Sensitivity Analysis of the Singular Value optimization Method for Antenna Characterization
No full textThe Singular Value optimization method has been successfully applied in the framework of the Near-Field antenna characterization. This approach provides a drastic reduction of the number of measurement points and of the measurement time with respect to standard and non-standard techniques. Here an analysis of the sensitivity of the method with respect to the noise is performed
Complex Waveforms Generation by SVO
No full textWe deal with an approach, based on the Singular Value Optimization (SVO) technique, for the synthesis of array-based generators of near-field complex waveforms. The approach selects the grid wherein enforcing the design specifications and the radiator locations to control the ill-conditioning associated to the determination of the array excitation coefficients. Following the SVO optimization, the array coefficients are determined by a Singular Value Decomposition (SVD). Numerical results are provided for the synthesis of the near-field scattered by a perfectly conducting sphere illuminated by an elementary dipole. © 2018 Antenna Measurement Techniques Association
- …
