A note on double edge diffraction for parallel wedges

Traffic noise measurements were made behind a low, earth berm and in an adjacent open field to estimate insertion loss. The traffic was comprised of a mix of light vehicles, heavy trucks, and some medium trucks. The berm had a height of 1.65 meters above the roadway and began at the outside shoulder of a four-lane highway along U.S. Highway 101 in Northern California. Two microphone positions were located on the far side of the berm at distances of 28 and 40 meters from the center of the near lane of vehicular traffic. Away from the berm, a microphone was placed in an open field at 28 meters from the highway at a site upstream of the berm. The difference between the open location and those behind the berm were 11.6 and 9.9 dB for the 28- and 40-meter locations, respectively. The reductions obtained with the berm are compared to double edge diffraction theory and acoustic scale model results from the literature. The results of this study are reviewed in this paper and a comparison to FHWA Traffic Noise Model results is presented.

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An incremental theory of double edge diffraction

Radio Science ◽

10.1029/2007rs003681 ◽

2007 ◽

Vol 42 (6) ◽

Cited By ~ 5

Author(s):

A. Toccafondi ◽

R. Tiberio

Keyword(s):

Incremental Theory ◽

Edge Diffraction ◽

Double Edge

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

International Journal of Electronics and Telecommunications ◽

10.2478/v10177-011-0017-8 ◽

2011 ◽

Vol 57 (1) ◽

pp. 115-120 ◽

Cited By ~ 2

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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