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Modelling of a monostatic borehole radar antenna
Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2006.
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| Format: | Thesis |
| Language: | English |
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Stellenbosch : University of Stellenbosch
2006
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| _version_ | 1867613875065585665 |
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| access_status_str | Open Access |
| author | Gouws, Marcel |
| author2 | Cloete, J. H. |
| author_browse | Cloete, J. H. Gouws, Marcel |
| author_facet | Cloete, J. H. Gouws, Marcel |
| author_sort | Gouws, Marcel |
| collection | Thesis |
| dc_rights_str_mv | University of Stellenbosch |
| description | Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2006. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/2967 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:43:05.531Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2006 |
| publishDateRange | 2006 |
| publishDateSort | 2006 |
| publisher | Stellenbosch : University of Stellenbosch |
| publisherStr | Stellenbosch : University of Stellenbosch |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/2967 Modelling of a monostatic borehole radar antenna Gouws, Marcel Cloete, J. H. Palmer, K. D. University of Stellenbosch. Faculty of Engineering. Dept. of Electrical and Electronic Engineering. Dissertations -- Electrical and electronic engineering Theses -- Electrical and electronic engineering Ground penetrating radar Radar -- Antennas Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2006. The successful operation of a pulsed monostatic borehole radar system requires that cur- rent on the antenna due to transmitter pulses subsides quickly. Deterioration of the radar antenna feed-point current settling times when deployed in water-¯lled boreholes showed that the radar system's performance is highly environmentally sensitive. Electromagnetic models are used to investigate this e®ect, since measuring the feed-point and radiative characteristics of an insulated antenna deployed in a borehole is practically impossible at present. A transmission line model for insulated antennas is utilized to model the borehole radar antenna in electrically dense media. Predicted input impedance values however do not correspond well to those from numerical ¯eld simulation software and the model is shown to be inadequate for modelling insulated antennas in environments of low conductivity. Radiated ¯eld results are however found to be accurate. A study of the feed-point and radiative characteristics of the borehole radar antenna in a range of di®erent borehole environment is performed using electromagnetic ¯eld simulation software. Results con¯rm that the borehole radar antenna has longer feed- point current settling times and degraded radiated pulse waveforms when deployed in water-¯lled boreholes. Simple lumped element networks with driving-port impedances approximately equal to antenna input impedances are synthesized from simulated input impedance results for a range of borehole environments. This allows diagnostics on the radar system to be performed in the laboratory, with the antenna load appearing as if the system were deployed in a borehole. The use of an antenna with distributed resistive and capacitive loading is proposed as a modi¯cation that would result in improved feed-point characteristics in water-¯lled boreholes. Results from simulations and experiments are presented that con¯rm that the new antenna design substantially reduces feed-point current settling times after the transmitter ¯res. 2006-10-11T06:32:00Z 2010-06-01T09:02:46Z 2006-10-11T06:32:00Z 2010-06-01T09:02:46Z 2006-03 Thesis http://hdl.handle.net/10019.1/2967 en University of Stellenbosch 4480132 bytes application/pdf application/pdf Stellenbosch : University of Stellenbosch |
| spellingShingle | Dissertations -- Electrical and electronic engineering Theses -- Electrical and electronic engineering Ground penetrating radar Radar -- Antennas Gouws, Marcel Modelling of a monostatic borehole radar antenna |
| title | Modelling of a monostatic borehole radar antenna |
| title_full | Modelling of a monostatic borehole radar antenna |
| title_fullStr | Modelling of a monostatic borehole radar antenna |
| title_full_unstemmed | Modelling of a monostatic borehole radar antenna |
| title_short | Modelling of a monostatic borehole radar antenna |
| title_sort | modelling of a monostatic borehole radar antenna |
| topic | Dissertations -- Electrical and electronic engineering Theses -- Electrical and electronic engineering Ground penetrating radar Radar -- Antennas |
| url | http://hdl.handle.net/10019.1/2967 |
| work_keys_str_mv | AT gouwsmarcel modellingofamonostaticboreholeradarantenna |