Roundoff algorithms for digital phase shifters that minimize beam shift
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Authors
Engle, Stanley E.
Subjects
Roundoff
Beam shift
Phase shifters
Bitsize
Pointing error
Null depth
Sidelobe
Beam shift
Phase shifters
Bitsize
Pointing error
Null depth
Sidelobe
Advisors
Jenn, David C.
Date of Issue
1992-03
Date
March 1992
Publisher
Monterey, California. Naval Postgraduate School
Language
en_US
Abstract
The performance of a phased array antenna depends upon the phase and amplitude distribution across the aperture. A continuous 13-near phase distribution is required for an efficient focussed beam, but practical phase shifters are digital devices and can only provide an approximation to a linear phase distribution. Consequently some type of roundoff criteria must be established. The method of roundoff affects the radiation pattern characteristics such as beam location and sidelobe level. Accurate target tracking requires that a radar have a small beam pointing error. Low sidelobes are also desirable to prevent jamming and the illumination of clutter. Therefore the goal was to select a roundoff criterion that provides a phase distribution across the aperture to minimize both the beam shift and the sidelobe levels, while simultaneously maximizing the gain. The methods examined are referred to regular roundoff, weighted random roundoff, running sum roundoff and symmetric running sum roundoff. The first two are in common use, but the third and fourth are new methods examined in this paper. It was demonstrated that the latter two have the beam shift of the four roundoff methods, without significantly degrading the other pattern properties.
Type
Thesis
Description
Series/Report No
Department
Department of Electrical and Computer Engineering
Organization
Naval Postgraduate School
Identifiers
NPS Report Number
Sponsors
Funder
Format
142 p.
Citation
Distribution Statement
Approved for public release; distribution is unlimited.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.