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2. PHD Thesis / Tesis PHD
3. Institute for Environment and Development / Institut Alam Sekitar dan Pembangunan (LESTARI)

Title:	Design analysis of v-shape dipole-based antenna for radio astronomy application
Authors:	Radial Anwar (P62737)
Supervisor:	Norbahiah Misran, Prof. Dr.
Keywords:	Radio astronomy Antennas design
Issue Date:	6-Jan-2015
Description:	Low-frequency radio astronomy has become an important and fascinating research area in the field of astronomy. However, to date, the front-end section for low-frequency radio telescope systems are still varied based on the observational channel, where specific optimization is required for each particular frequency. In this thesis, a general method in designing antennas meant for low-frequency radio telescope system is proposed. The method is applicable to design an antenna for any given frequency, ranging from of about 13 MHz to 1420 MHz. V-shape dipole-based antenna concept has been adopted in the method as it provides low Standing Wave Ratio (SWR) at the terminal point, as well as a broader beamwidth compared to the conventional half-wavelength dipole antenna. The method has been derived from simulation and statistical analysis. Rod-shaped conducting material with the size of six millimeters has been utilized in all simulations. The parametric studies have been analyzed and optimized using numerical electromagnetic code based software (NEC4WIN95VM). Low SWR has been obtained in all optimized frequencies, down to 1.005. The method has been statistically analyzed and each of the equations in it has a very small standard deviation, encouraging a good prospect for its applicability. Designs in two different frequencies (408 MHz and 1420 MHz) have been constructed and measured to verify the simulation results. Measurement results have shown a good agreement with simulation, where the achieved measured peaks have a small margin of error down to 0.7%. The prototypes have been utilized as the front-end sections for a radio telescope system in several solar observations. The analysis on the observed data and correlation with data from another observatory indicate a good possibility that the radio telescope system has detected several type III solar bursts. The narrow bandwidth of the prototypes has been proven as an advantage, as it helps the system to suppress Radio Frequency Interferences (RFI), allowing a relatively high gain setup in the system without suffering data saturation. Other methods in utilizing parasitic elements to reduce the antenna beamwidth and three-antenna system to increase the observational time also have been investigated and applied in one of the prototypes. An equation in estimating an array radio telescope system’s beamwidth also has been developed. Statistical analysis has shown a very small standard deviation for the equation, hence it can also be proposed as a new general method.,Ph.D.
Pages:	107
Publisher:	UKM, Bangi
Appears in Collections:	Institute for Environment and Development / Institut Alam Sekitar dan Pembangunan (LESTARI)

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