Far-field polar patterns of a surface-wave array at 20 Mc/s

1965 ◽  
Vol 1 (7) ◽  
pp. 195
Author(s):  
J.F. Ward
Keyword(s):  
Surface Wave ◽  
Far Field

scholarly journals Effective surface conductivity of optical hyperbolic metasurfaces: from far-field characterization to surface wave analysis

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Oleh Y. Yermakov ◽  
Dmitry V. Permyakov ◽  
Filipp V. Porubaev ◽  
Pavel A. Dmitriev ◽  
Anton K. Samusev ◽  
...  
Keyword(s):  
Surface Wave ◽  
Surface Conductivity ◽  
Far Field ◽  
Wave Analysis ◽  
Effective Surface

scholarly journals Acoustic Far-Field Hypersonic Surface Wave Detection with Single Plasmonic Nanoantennas

2018 ◽  
Vol 121 (25) ◽  
Author(s):  
Rodrigo Berte ◽  
Fabricio Della Picca ◽  
Martín Poblet ◽  
Yi Li ◽  
Emiliano Cortés ◽  
...  
Keyword(s):  
Surface Wave ◽  
Far Field ◽  
Wave Detection ◽  
Plasmonic Nanoantennas

scholarly journals Near-field to far-field transformation applied to UHF antennas over lossy ground

2019 ◽  
Vol 12 (3) ◽  
pp. 227-232
Author(s):  
Nicolas Bourey ◽  
Muriel Darces ◽  
Yves Chatelon ◽  
Marc Hélier
Keyword(s):  
Surface Wave ◽  
Near Field ◽  
Field Measurements ◽  
Directional Antennas ◽  
Far Field ◽  
Biconical Antenna ◽  
Field Transformation ◽  
Set Up ◽  
Dipole Sources

AbstractThis paper deals with a near-field to far-field transformation able to predict the radiation of UHF antennas located over a lossy ground. From in-situ near-field measurements, an equivalent set of dipole sources is obtained as a model of the characterized antenna. The paper details the main steps of the transformation and describes the specific experimental set-up designed for the application. Simple directional antennas (monopoles array) as well as more complex omnidirectional antennas (like a biconical antenna as a scaled-down model of a HF antenna) have been tested in realistic environments. This approach is very efficient for separating the contributions of the radiated waves: the sky wave and the surface wave.

scholarly journals Exploring surface wave interaction with angled defects in the near and far field

2011 ◽  
Vol 278 ◽  
pp. 012011
Author(s):  
B Dutton ◽  
A R Clough ◽  
M H Rosli ◽  
R S Edwards
Keyword(s):  
Surface Wave ◽  
Wave Interaction ◽  
Far Field

Scattering of SH-waves by an irregularity at the mass-loaded boundary of a semi-infinite elastic medium

1975 ◽  
Vol 342 (1629) ◽  
pp. 237-257 ◽  
Keyword(s):  
Surface Wave ◽  
Elastic Medium ◽  
Radiation Pattern ◽  
Far Field ◽  
Angle Of Incidence ◽  
Bulk Wave ◽  
Mass Loading ◽  
Sh Waves ◽  
Field Radiation ◽  
Fourier Type

A rigorous theory of the scattering of two dimensional SH-waves by an irregularity at the mass-loaded boundary of a semi-infinite elastic medium is presented. Two types of surface irregularities are considered: (a) an indentation, (b) a discontinuity in mass-loading. n mass-loading. The incident SH-wave is taken to be either (1) a bulk wave or (2) a surface wave. For the two types of irregularities, the corresponding boundary value problem (of the third kind) is solved by employing a suitably chosen Green function; the latter is represented as a Fourier type of integral. This procedure leads to integral equations in which the relevant field distributions on the disturbed parts of the boundary occur as unknown quantities. In case (1) the amplitudes of the launched surface wave are computed; in case (2) the transmission and the reflexion factor are computed. For both cases, expressions are obtained for the far-field radiation pattern of the scattered bulk wave. In an appendix a reciprocity relation is derived between the amplitude of the launched surface wave as a function of the angle of incidence in case (1) on one hand and the far-field radiation pattern of the scattered bulk wave in case (2) on the other hand. Numerical results are presented for the following configurations: a triangularly prismatic indentation, a rigid strip loading and a traction-free interruption in the mass-loading.

scholarly journals Surface Wave Generation and Propagation on Metallic Subwavelength Structures Measured by Far-Field Interferometry

2006 ◽  
Vol 96 (21) ◽  
Author(s):  
G. Gay ◽  
O. Alloschery ◽  
B. Viaris de Lesegno ◽  
J. Weiner ◽  
H. J. Lezec
Keyword(s):  
Surface Wave ◽  
Wave Generation ◽  
Subwavelength Structures ◽  
Far Field

Possible applications of fraunhofer holography in high resolution electron microscopy

1978 ◽  
Vol 36 (1) ◽  
pp. 222-223 ◽  
Author(s):  
N. Bonnet ◽  
M. Troyon ◽  
P. Gallion
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Transfer Function ◽  
Radiation Damage ◽  
High Resolution Electron Microscopy ◽  
Far Field ◽  
Field Region ◽  
Crystalline Materials ◽  
Resolution Electron ◽  
The Ideal

Two main problems in high resolution electron microscopy are first, the existence of gaps in the transfer function, and then the difficulty to find complex amplitude of the diffracted wawe from registered intensity. The solution of this second problem is in most cases only intended by the realization of several micrographs in different conditions (defocusing distance, illuminating angle, complementary objective apertures…) which can lead to severe problems of contamination or radiation damage for certain specimens.Fraunhofer holography can in principle solve both problems stated above (1,2). The microscope objective is strongly defocused (far-field region) so that the two diffracted beams do not interfere. The ideal transfer function after reconstruction is then unity and the twin image do not overlap on the reconstructed one.We show some applications of the method and results of preliminary tests.Possible application to the study of cavitiesSmall voids (or gas-filled bubbles) created by irradiation in crystalline materials can be observed near the Scherzer focus, but it is then difficult to extract other informations than the approximated size.

Exit-surface wave reconstruction using a focal series

1992 ◽  
Vol 50 (2) ◽  
pp. 988-989
Author(s):  
W.J. de Ruijter ◽  
M.R. McCartney ◽  
David J. Smith ◽  
J.K. Weiss
Keyword(s):  
Surface Wave ◽  
Spherical Aberration ◽  
Data Extraction ◽  
High Sensitivity ◽  
Geometric Distortion ◽  
Variation Method ◽  
Objective Lens ◽  
Immediate Reconstruction ◽  
Exit Surface ◽  
Electron Microscopes

Further advances in resolution enhancement of transmission electron microscopes can be expected from digital processing of image data recorded with slow-scan CCD cameras. Image recording with these new cameras is essential because of their high sensitivity, extreme linearity and negligible geometric distortion. Furthermore, digital image acquisition allows for on-line processing which yields virtually immediate reconstruction results. At present, the most promising techniques for exit-surface wave reconstruction are electron holography and the recently proposed focal variation method. The latter method is based on image processing applied to a series of images recorded at equally spaced defocus.Exit-surface wave reconstruction using the focal variation method as proposed by Van Dyck and Op de Beeck proceeds in two stages. First, the complex image wave is retrieved by data extraction from a parabola situated in three-dimensional Fourier space. Then the objective lens spherical aberration, astigmatism and defocus are corrected by simply dividing the image wave by the wave aberration function calculated with the appropriate objective lens aberration coefficients which yields the exit-surface wave.

Sign in / Sign up

Export Citation Format

Share Document