Microstrip spatial filters for the H-plane pattern control of microstrip antennas

F. Bonvin; S. A. Bokhari; J. F. Zürcher; F. E. Gardiol

doi:10.1002/mop.4650050802

Radiation pattern control in microstrip antennas

Proceedings of 1996 Canadian Conference on Electrical and Computer Engineering ◽

10.1109/ccece.1996.548288 ◽

2002 ◽

Author(s):

L. Shafai ◽

S. Noghanian

Keyword(s):

Radiation Pattern ◽

Microstrip Antennas ◽

Pattern Control

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Simple, Compact, and Multiband Frequency Selective Surfaces Using Dissimilar Sierpinski Fractal Elements

International Journal of Antennas and Propagation ◽

10.1155/2015/614780 ◽

2015 ◽

Vol 2015 ◽

pp. 1-5 ◽

Cited By ~ 8

Author(s):

Clarissa de Lucena Nóbrega ◽

Marcelo Ribeiro da Silva ◽

Paulo Henrique da Fonseca Silva ◽

Adaildo Gomes D’Assunção ◽

Gláucio Lima Siqueira

Keyword(s):

High Frequency ◽

Design Methodology ◽

Frequency Tuning ◽

Microstrip Antennas ◽

Frequency Selective Surfaces ◽

Experimental Characterization ◽

Spatial Filters ◽

Frequency Responses ◽

Frequency Selective

This paper presents a design methodology for frequency selective surfaces (FSSs) using metallic patches with dissimilar Sierpinski fractal elements. The transmission properties of the spatial filters are investigated for FSS structures composed of two alternately integrated dissimilar Sierpinski fractal elements, corresponding to fractal levelsk=1, 2, and 3. Two FSS prototypes are fabricated and measured in the range from 2 to 12 GHz to validate the proposed fractal designs. The FSSs with dissimilar Sierpinski fractal patch elements are printed on RT/Duroid 6202 high frequency laminate. The experimental characterization of the FSS prototypes is accomplished through two different measurement setups composed of commercial horns and elliptical monopole microstrip antennas. The obtained results confirm the compactness and multiband performance of the proposed FSS geometries, caused by the integration of dissimilar fractal element. In addition, the proposed FSSs exhibited frequency tuning ability on the multiband frequency responses. Agreement between simulated and measured results is reported.

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Comparison of Deterministic and Linear Cosine Spatial Filtering of Transmission Electron Micrographs

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100096230 ◽

1972 ◽

Vol 30 ◽

pp. 596-597

Author(s):

David A. Ansley

Keyword(s):

Spherical Aberration ◽

Focal Length ◽

Chromatic Aberration ◽

Spatial Filter ◽

Operating Conditions ◽

Objective Lens ◽

List Type ◽

Spatial Filters ◽

Transmission Electron ◽

Wide Range

The coherence of the electron flux of a transmission electron microscope (TEM) limits the direct application of deconvolution techniques which have been used successfully on unmanned spacecraft programs. The theory assumes noncoherent illumination. Deconvolution of a TEM micrograph will, therefore, in general produce spurious detail rather than improved resolution.A primary goal of our research is to study the performance of several types of linear spatial filters as a function of specimen contrast, phase, and coherence. We have, therefore, developed a one-dimensional analysis and plotting program to simulate a wide 'range of operating conditions of the TEM, including adjustment of the:(1) Specimen amplitude, phase, and separation(2) Illumination wavelength, half-angle, and tilt(3) Objective lens focal length and aperture width(4) Spherical aberration, defocus, and chromatic aberration focus shift(5) Detector gamma, additive, and multiplicative noise constants(6) Type of spatial filter: linear cosine, linear sine, or deterministic

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A light optical diffractometer for electron microscopical images operating in line

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100107575 ◽

1978 ◽

Vol 36 (1) ◽

pp. 86-87

Author(s):

P. Bonhomme ◽

A. Beorchia

Keyword(s):

Electron Microscopy ◽

Electron Transfer ◽

Electron Microscope ◽

Image Converter ◽

Coherent Light ◽

Spatial Filters ◽

Electron Image ◽

Electron Microscopical ◽

Working Parameters ◽

Amorphous Part

We have already described (1.2.3) a device using a pockel's effect light valve as a microscopical electron image converter. This converter can be read out with incoherent or coherent light. In the last case we can set in line with the converter an optical diffractometer. Now, electron microscopy developments have pointed out different advantages of diffractometry. Indeed diffractogram of an image of a thin amorphous part of a specimen gives information about electron transfer function and a single look at a diffractogram informs on focus, drift, residual astigmatism, and after standardizing, on periods resolved (4.5.6). These informations are obvious from diffractogram but are usualy obtained from a micrograph, so that a correction of electron microscope parameters cannot be realized before recording the micrograph. Diffractometer allows also processing of images by setting spatial filters in diffractogram plane (7) or by reconstruction of Fraunhofer image (8). Using Electrotitus read out with coherent light and fitted to a diffractometer; all these possibilities may be realized in pseudoreal time, so that working parameters may be optimally adjusted before recording a micrograph or before processing an image.

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