Topic
Near and far field
About: Near and far field is a research topic. Over the lifetime, 15922 publications have been published within this topic receiving 220571 citations.
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TL;DR: In this article, a comprehensive electrooptic field-mapping technique was applied to the characterization of near-field radiation patterns above a microstrip patch antenna, which revealed the transition from the near field to the far field of the radiation pattern.
Abstract: A comprehensive electrooptic field-mapping technique is applied to the characterization of near-field radiation patterns above a microstrip patch antenna. The amplitude and phase maps of three orthogonal electric-field components, measured using electrooptic crystals above the patch, also have revealed the transition from the near field to the far field of the radiation pattern. In addition, experimental results have been compared with a finite-element method (FEM) simulation. The measurememts show superior results to the FEM simulation, especially in terms of spatial resolution and data acquisition times. Furthermore, the scattering parameter S/sub 11/ for the patch antenna has been calculated from the electrooptic measurement results of standing waves on the feeding line and compared with results from a conventional network analyzer.
127 citations
TL;DR: The enhanced transmission of electromagnetic waves through a single subwavelength aperture by using a split-ring resonator (SRR) at microwave frequencies is reported and 740-fold transmission enhancement is obtained by exciting the electric resonance of SRR.
Abstract: We report the enhanced transmission of electromagnetic waves through a single subwavelength aperture by using a split-ring resonator (SRR) at microwave frequencies. By placing a single SRR at the near field of the aperture, strongly localized electromagnetic fields are effectively coupled to the aperture with a radius that is 20 times smaller than the resonance wavelength (r/lambda=0.05). We obtained 740-fold transmission enhancement by exciting the electric resonance of SRR. A different coupling mechanism, through the magnetic resonance of SRR, is also verified to lead to enhanced transmission.
126 citations
TL;DR: In this article, the statistical, spatial and temporal coherence properties of electromagnetic radiation scattered into the far field by a deep random phase screen are investigated, and it is shown that significant departures from Gaussian behaviour can occur even when the phase correlation length is much smaller than the dimensions of the scattering region.
Abstract: The statistical, spatial and temporal coherence properties of electromagnetic radiation scattered into the far field by a deep random phase screen are investigated. It is shown that significant departures from Gaussian behaviour can occur even when the phase correlation length is much smaller than the dimensions of the scattering region-a situation in which the central limit theorem might be expected to apply. Formulae are derived relating these departures to elementary properties of the scattering structure, which may therefore be determined by measurement of the fluctuations in the scattered radiation. Application of the results to scattering from very rough surfaces is discussed.
123 citations
TL;DR: In this paper, the far field radiation patterns of finite-size resistively loaded horizontal electric dipoles lying on a low-loss dielectric half-space are computed, where the amplitude of the dipole excitation current is determined by a cosine distribution that accurately simulates the resistive loading.
123 citations