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November 2006 Full Issue

ACES Journal Paper
Year: 2006      Volume: 21      Number: 3
Click here to download PDF     File Size: 12430 KB

ACES Journal February 2016 Full

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ACES Journal Paper
Year: 2016      Volume: 31      Number: 2
Click here to download PDF     File Size: 12353 KB

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ACES January 2010 Full Journal

ACES Journal Paper
Year: 2010      Volume: 25      Number: 1
Click here to download PDF     File Size: 9311 KB

March 2005 Full Journal Download

ACES Journal Paper
Year: 2005      Volume: 20      Number: 1
Click here to download PDF     File Size: 4893 KB

Using Adaptive Estimation to Minimize the Number of Samples Needed to Develop a Pattern to a Specified Uncertainty

Edmund K. Miller
ACES Journal Paper
Year: 2002      Volume: 17      Number: 3
Click here to download PDF     File Size: 278 KB

Obtaining far-field patterns in electromagnetics or acoustics, although generally not as computationally expensive as solving for the sources induced on an object, can none-the-less at times be a substantial fraction of the overall computer time associated with some problems. This can be especially the case in determining the monostatic radar cross section of large objects, since the current distribution must be computed for each incidence angle or when using physical optics to determine the radiation patterns of large reflector antennas. In addition, when employing the point sampling and linear interpolation of the far field that is most often used to develop such patterns, it can be necessary to sample very finely in angle to avoid missing fine details such as nulls. A procedure based on model-based parameter estimation is described here that offers the opportunity of reducing the number of samples needed while developing an easily computed and continuous representation of the pattern. It employs windowed, low-order, overlapping fitting models whose parameters are estimated from the sparsely sampled far-field values. The fitting models themselves employ either discrete-source approximations to the radiating currents or Fourier models of the far field. For the cases investigated, as few as 1.5 to 2 samples per far-field lobe are found to be sufficient to develop a radiation-pattern estimate that is accurate to 0.1 dB, and 2.5 samples per lobe for a simple scatterer. In general, however, the sampling density is not determined by the lobe count alone, but by the effective rank of the field over the observation window, which in turn is a function of both the aperture size and the spatial variation of the source distribution within that aperture.

March 2004 ACES Newsletter full download

ACES Newsletter Paper
Year: 2004      Volume: 19      Number: 1
Click here to download PDF     File Size: 6791 KB

ACES 2004 Conference Information

ACES Newsletter Paper
Year: 2004      Volume: 19      Number: 1
Click here to download PDF     File Size: 224 KB

Error Bound due to the Random Position Errors in Adaptive Processing Using a Nonuniformly Spaced Array

S. Hwang
ACES Conference Paper
Year: 2004 - Smart Antennas and Computational Electromagnetics
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In this paper, the gain power error bound due to random position errors in the array elements is presented. From the gain power error bound, the relationship between the output signal to interference and noise ratio (OSINR) and the coefficient of variation of the powerdensity function is investigated by adaptive processing using a single snapshot of the measured voltage at the feed points of a semi-circular antenna (SCA) elements in an array.

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