Investigations on Low Cross Polarized Antenna Systems at Microwave Frequencies (Record no. 54488)
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| 000 -LEADER | |
|---|---|
| fixed length control field | 03295ngm a2200193 a 4500 |
| 008 - FIXED-LENGTH DATA ELEMENTS--GENERAL INFORMATION | |
| fixed length control field | 140223b2010 xxu||||| |||| 00| 0 eng d |
| 082 ## - DEWEY DECIMAL CLASSIFICATION NUMBER | |
| Classification number | TT000001 |
| Item number | PUJ |
| 100 ## - MAIN ENTRY--PERSONAL NAME | |
| Personal name | Pujara, Dhaval Kumar |
| 245 ## - TITLE STATEMENT | |
| Title | Investigations on Low Cross Polarized Antenna Systems at Microwave Frequencies |
| Statement of responsibility, etc | by Dhaval Kumar Pujara |
| 260 ## - PUBLICATION, DISTRIBUTION, ETC. (IMPRINT) | |
| Place of publication, distribution, etc | Ahmedabad |
| Name of publisher, distributor, etc | Nirma Institute of Technology |
| Date of publication, distribution, etc | 2010 |
| 300 ## - PHYSICAL DESCRIPTION | |
| Extent | 120p Ph. D. Thesis with Synopsis and CD |
| 500 ## - GENERAL NOTE | |
| General note | Guided by: Dr. S. B. Sharma with Synopsis and CD 07EXTPHDE14<br/><br/>ABSTRACT:<br/><br/>In view of the widespread applications of the offset parabolic reflector antennas in satellite communications, microwave radiometers, radio astronomy, monopulse tracking radar, etc., the research work described in the thesis is mainly focused on improving the performance of offset parabolic reflector antennas. Although, the offset parabolic reflector configuration offers significant advantages as compared to the front-fed parabolic reflector antenna, it suffers from two serious drawbacks. Due to the structural asymmetry, when illuminated by a linearly polarized primary feed, it generates high cross-polarization. While in case of a circularly polarized feed, it results in beam squinting. The presence of high crosspolarization in the antenna radiation patterns implies the loss of energy in the undesired polarization, which ultimately results into reduction of the antenna efficiency. High degree of cross-polarization degrades the performance of the communication channel and can cause measurement errors in case of remote-sensing applications. In monopulse tracking radars, the high cross-polarization creates boresight-jitter (boresight uncertainty), which severely affects the tracking accuracies. Considering these undesirable effects of high cross-polarization, it becomes necessary to develop a suitable technique to suppress the unwanted cross-polarization of the offset parabolic reflector antenna. In the present thesis, the high cross-polarization of the offset parabolic reflector has been suppressed by using a multi-mode matched feed. The concept of matched feed is thoroughly described at the beginning of the thesis. The multi-mode matched feed has been realized in three different waveguide structures, i.e., rectangular, cylindrical and corrugated structure. The detailed designs of all the three matched feed structures have been presented in the thesis. Through extensive numerical as well as experimental results, it has been verified that the proposed matched feeds effectively suppress the undesired high cross-polarization of the offset parabolic reflector antenna. The feeds also remove the beam squinting in the secondary radiation pattern of the reflector, when circular polarization is employed. Finally, a few practical applications of the proposed feeds are discussed and the corresponding results are summarized in the thesis. |
| 856 ## - ELECTRONIC LOCATION AND ACCESS | |
| Uniform Resource Identifier | http://repository.nirmauni.ac.in/jspui/handle/123456789/2688 |
| Public note | Institute Repository (Campus Access) |
| 856 ## - ELECTRONIC LOCATION AND ACCESS | |
| Uniform Resource Identifier | http://shodhganga.inflibnet.ac.in/handle/10603/2693 |
| Public note | Sodhganga |
| 942 ## - ADDED ENTRY ELEMENTS (KOHA) | |
| Source of classification or shelving scheme | Dewey Decimal Classification |
| Koha item type | Thesis |
| 995 ## - RECOMMENDATION 995 [LOCAL, UNIMARC FRANCE] | |
| Origin of item (home branch) (free text) | Technology Thesis |
| Genre | TT000001 |
| Section | TT000001 |
| Recipient parent organisation code | TT000001 |
| 995 ## - RECOMMENDATION 995 [LOCAL, UNIMARC FRANCE] | |
| Origin of item (home branch) (free text) | Technology Thesis CD |
| Genre | TT000001-1 |
| Section | TT000001 |
| Recipient parent organisation code | TT000001-1 |
| 995 ## - RECOMMENDATION 995 [LOCAL, UNIMARC FRANCE] | |
| Origin of item (home branch) (free text) | Technology Synopsis |
| Genre | TT000001-2 |
| Section | TT000001 |
| Recipient parent organisation code | TT000001-2 |
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