An analytic secondary source model of edge diffraction impulse responses

1999 ◽  
Vol 106 (5) ◽  
pp. 2331-2344 ◽  
Author(s):  
U. Peter Svensson ◽  
Roger I. Fred ◽  
John Vanderkooy
Keyword(s):  
Source Model ◽  
Secondary Source ◽  
Impulse Responses ◽  
Edge Diffraction

Radiation Characteristics of Heat Sink in Propulsive Wheel of Mobile Robots

2014 ◽  
Vol 494-495 ◽  
pp. 1294-1297
Author(s):  
Yan Xu ◽  
He Xu ◽  
Yu Kun Luan ◽  
X.Z. Gao ◽  
Kai Xue
Keyword(s):  
Mobile Robots ◽  
Electromagnetic Interference ◽  
Heat Sink ◽  
Evaluation Criteria ◽  
Source Model ◽  
Electromagnetic Properties ◽  
Internal Space ◽  
Secondary Source ◽  
Shielding Effectiveness ◽  
Electro Magnetic

Electromagnetic interference easily appears in the propulsive wheel - a key component of the mobile robots, because internal space of propulsive wheel is very small, there are numerous electronic devices, and signal communication is complex. So electromagnetic shielding is very important for the propulsive wheel. In this paper, a wheel model and an equivalent source model of electromagnetic interference of the wheel were developed based on considerations of the internal electromagnetic properties. At the same time, a secondary source of electromagnetic interference is formed by heat sink. Hence, shielding effectiveness is taken as one of the evaluation criteria for the Electro-Magnetic Compatibility (EMC) problem, and the Genetic Algorithm (GA) in the software Ansoft HFSS platform was used to optimize the first resonance frequency of heat sink.

Are snitches taken seriously? An investigation of post-identification feedback from a secondary source

2012 ◽  
Author(s):  
William Blake Erickson ◽  
James Michael Lampinen ◽  
Jeffrey Neuschatz ◽  
Stacy Wetmore ◽  
Christopher S. Peters ◽  
...  
Keyword(s):  
Secondary Source

A famine in Surat in 1631 and Dodos on Mauritius: a long lost manuscript rediscovered

2017 ◽  
Vol 44 (1) ◽  
pp. 134-150 ◽  
Author(s):  
R. Winters ◽  
J. P. Hume ◽  
M. Leenstra
Keyword(s):  
English Translation ◽  
East India Company ◽  
Secondary Source ◽  
Dutch East India Company ◽  
The Status ◽  
Insight Into

In 1887 Dutch archivist A. J. Servaas van Rooijen published a transcript of a hand-written copy of an anonymous missive or letter, dated 1631, about a horrific famine and epidemic in Surat, India, and also an important description of the fauna of Mauritius. The missive may have been written by a lawyer acting on behalf of the Dutch East India Company (VOC). It not only gives details about the famine, but also provides a unique insight into the status of endemic and introduced Mauritius species, at a time when the island was mostly uninhabited and used only as a replenishment station by visiting ships. Reports from this period are very rare. Unfortunately, Servaas van Rooijen failed to mention the location of the missive, so its whereabouts remained unknown; as a result, it has only been available as a secondary source. Our recent rediscovery of the original hand-written copy provides details about the events that took place in Surat and Mauritius in 1631–1632. A full English translation of the missive is appended.

Influence of the Aperture Edge Diffraction Effects on the Mutual Coupling Compensation Technique in Small Planar Antenna Arrays

2011 ◽  
Vol 57 (1) ◽  
pp. 115-120 ◽  
Author(s):  
Mariusz Zamłyński ◽  
Piotr Słobodzian
Keyword(s):  
Antenna Arrays ◽  
Mutual Coupling ◽  
Planar Antenna ◽  
Sidelobe Level ◽  
Edge Diffraction ◽  
Narrow Angle ◽  
Compensation Technique ◽  
Diffraction Effects ◽  
Linear Antenna Arrays

Influence of the Aperture Edge Diffraction Effects on the Mutual Coupling Compensation Technique in Small Planar Antenna Arrays In this paper the quality of a technique to compensate for mutual coupling (and other phenomena) in small linear antenna arrays is investigated. The technique consists in calculation of a coupling matrix, which is than used to determine corrected antenna array excitation coefficients. Although the technique is known for more than 20 years, there is still very little information about how different phenomena existing in a real antenna arrays influence its performance. In this paper two models of antenna arrays are used. In the first model the effect of mutual coupling is separated from the aperture edge diffraction. In the second model antenna both mutual coupling and aperture edge diffraction effects are included. It is shown that mutual coupling itself can be compensated very well and an ultralow sidelobe level (i.e. -50 dB) could be achieved in practice. In the presence of diffraction effects -46.3 dB sidelobe level has been attained, but radiation pattern can be controled only in narrow angle range (i.e. up to ±60°).

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