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Performance Enhancement of Space-Tim...

Rivera-Albino, Alix.

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Performance Enhancement of Space-Time Adaptive Processing for GPS and Microstrip Antenna Design Using Ferrite Rings.

Record Type:	Language materials, printed : Monograph/item
Title/Author:	Performance Enhancement of Space-Time Adaptive Processing for GPS and Microstrip Antenna Design Using Ferrite Rings./
Author:	Rivera-Albino, Alix.
Description:	123 p.
Notes:	Source: Dissertation Abstracts International, Volume: 75-03(E), Section: B.
Contained By:	Dissertation Abstracts International75-03B(E).
Subject:	Physics, Electricity and Magnetism. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3603312
ISBN:	9781303578021

Performance Enhancement of Space-Time Adaptive Processing for GPS and Microstrip Antenna Design Using Ferrite Rings.
Rivera-Albino, Alix.

Performance Enhancement of Space-Time Adaptive Processing for GPS and Microstrip Antenna Design Using Ferrite Rings. - 123 p.

Source: Dissertation Abstracts International, Volume: 75-03(E), Section: B.

Thesis (Ph.D.)--Arizona State University, 2013.

Global Positioning System (GPS) is a navigation system widely used in civilian and military application, but its accuracy is highly impacted with consequential fading, and possible loss of communication due to multipath propagation and high power interferences. This dissertation proposes alternatives to improve the performance of the GPS receivers to obtain a system that can be reliable in critical situations. The basic performance of the GPS receiver consists of receiving the signal with an antenna array, delaying the signal at each antenna element, weighting the delayed replicas, and finally, combining the weighted replicas to estimate the desired signal. Based on these, three modifications are proposed to improve the performance of the system. The first proposed modification is the use of the Least Mean Squares (LMS) algorithm with two variations to decrease the convergence time of the classic LMS while achieving good system stability. The results obtained by the proposed LMS demonstrate that the algorithm can achieve the same stability as the classic LMS using a small step size, and its convergence rate is better than the classic LMS using a large step size. The second proposed modification is to replace the uniform distribution of the time delays (or taps) by an exponential distribution that decreases the bit-error rate (BER) of the system without impacting the computational efficiency of the uniform taps. The results show that, for a BER of 0.001, the system can operate with a 1 to 2 dB lower signal-to-noise ratio (SNR) when an exponential distribution is used rather than a uniform distribution. Finally, the third modification is implemented in the design of the antenna array. In this case, the gain of each microstrip element is enhanced by embedding ferrite rings in the substrate, creating a hybrid substrate. The ferrite rings generates constructive interference between the incident and reflected fields; consequently, the gain of a single microstrip element is enhanced by up to 4 dB. When hybrid substrates are used in microstrip element arrays, a significant enhancement in angle range is achieved for a given reflection coefficient compared to using a conventional substrate.

ISBN: 9781303578021Subjects--Topical Terms:

1019535
Physics, Electricity and Magnetism.

Performance Enhancement of Space-Time Adaptive Processing for GPS and Microstrip Antenna Design Using Ferrite Rings.
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100 1 $a Rivera-Albino, Alix. $3 2101294
245 1 0 $a Performance Enhancement of Space-Time Adaptive Processing for GPS and Microstrip Antenna Design Using Ferrite Rings.
300 $a 123 p.
500 $a Source: Dissertation Abstracts International, Volume: 75-03(E), Section: B.
500 $a Adviser: Constantine A. Balanis.
502 $a Thesis (Ph.D.)--Arizona State University, 2013.
520 $a Global Positioning System (GPS) is a navigation system widely used in civilian and military application, but its accuracy is highly impacted with consequential fading, and possible loss of communication due to multipath propagation and high power interferences. This dissertation proposes alternatives to improve the performance of the GPS receivers to obtain a system that can be reliable in critical situations. The basic performance of the GPS receiver consists of receiving the signal with an antenna array, delaying the signal at each antenna element, weighting the delayed replicas, and finally, combining the weighted replicas to estimate the desired signal. Based on these, three modifications are proposed to improve the performance of the system. The first proposed modification is the use of the Least Mean Squares (LMS) algorithm with two variations to decrease the convergence time of the classic LMS while achieving good system stability. The results obtained by the proposed LMS demonstrate that the algorithm can achieve the same stability as the classic LMS using a small step size, and its convergence rate is better than the classic LMS using a large step size. The second proposed modification is to replace the uniform distribution of the time delays (or taps) by an exponential distribution that decreases the bit-error rate (BER) of the system without impacting the computational efficiency of the uniform taps. The results show that, for a BER of 0.001, the system can operate with a 1 to 2 dB lower signal-to-noise ratio (SNR) when an exponential distribution is used rather than a uniform distribution. Finally, the third modification is implemented in the design of the antenna array. In this case, the gain of each microstrip element is enhanced by embedding ferrite rings in the substrate, creating a hybrid substrate. The ferrite rings generates constructive interference between the incident and reflected fields; consequently, the gain of a single microstrip element is enhanced by up to 4 dB. When hybrid substrates are used in microstrip element arrays, a significant enhancement in angle range is achieved for a given reflection coefficient compared to using a conventional substrate.
590 $a School code: 0010.
650 4 $a Physics, Electricity and Magnetism. $3 1019535
650 4 $a Engineering, Electronics and Electrical. $3 626636
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710 2 $a Arizona State University. $b Electrical Engineering. $3 1671741
773 0 $t Dissertation Abstracts International $g 75-03B(E).
790 $a 0010
791 $a Ph.D.
792 $a 2013
793 $a English
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3603312