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- Ong, J. Y., et al.
(author)
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Performance Analysis of Stacked Capacitive Antenna for Lightning Remote Sensing
- 2018
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In: 2018 INTERNATIONAL CONFERENCE ON ELECTRICAL ENGINEERING AND COMPUTER SCIENCE (ICECOS). - : IEEE. - 9781538657218 ; , s. 305-308
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Conference paper (peer-reviewed)abstract
- Antennas are the important elements in the lightning detection system. To improve performance of the lightning detection system, it is so necessary to improve the efficiency of the antennas. There are two types of antennas used in the system which are capacitive antenna for electric field sensing and loop antenna for magnetic field sensing Pi. Both of these antennas arc big in size and causing inconvenient during set up. Thus, small and portable antennas are designed. It is so important to remain or improve the sensitivity of the antennas even though it is small in size. Stacking method is used in capacitive antenna by increase copper plate layer in between the parallel plate antenna. After prototype the multi stacked capacitive antenna, performance analysis is carried out. Performances of the antennas are compared using CST simulation and hardware set up. Multi-stacked capacitive antenna is compared with the single plate antenna and found that the performance of the antenna increases as the stacked number increases.
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- Seah, B. Y., et al.
(author)
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Narrow Bipolar Events within Reversal Distance and Associated UHF-VHF Emissions
- 2019
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In: 2019 3RD INTERNATIONAL CONFERENCE ON ELECTRICAL ENGINEERING AND COMPUTER SCIENCE (ICECOS 2019). - : IEEE. - 9781728147147 ; , s. 132-136
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Conference paper (peer-reviewed)abstract
- This paper investigates the characteristics of the ultra-high frequency (UHF) and Very High Frequency (VHF) emissions that associate with negative narrow bipolar events (NBEs) which occurred within reversal distance, drev of the base station. The UHF emissions were captured by using a parallel plates antenna with its center frequency at 0.97 GHz and 20 MHz bandwidth. There are thirteen samples whereby their VHF and FF signals were leaded by their corresponding UHF about (102.25 +/- 125.48) ns and (692.13 +/- 382.36) ns respectively. All the UHF were found to behave like continuous bursting while some of the VHF consisted of certain periods within its burst train whereby there was no any sign of pulse during that period.
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- Baharin, S. A. S., et al.
(author)
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Wavelet Analysis of the Onset of VHF and Microwave Radiation Emitted by Lightning
- 2018
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In: 2018 INTERNATIONAL CONFERENCE ON ELECTRICAL ENGINEERING AND COMPUTER SCIENCE (ICECOS). - : IEEE. - 9781538657218 ; , s. 297-300
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Conference paper (peer-reviewed)abstract
- Lightning flash is an electrical discharge in air (dielectric breakdown) which emits electromagnetic (FM) fields across very wide spectra from a few Hertz up to visible wavelength. Electrical breakdown process is an important event that initiates lightning. For electrical breakdown process to occur, it must fulfill two conditions which are at least has one free electron and the electric field region is more than 3 MV/m. This process starts with electron avalanche in millimeter scale then grows into streamer in centimeter scale. Lastly, from streamer it will grow into leader in meter scale. It has already established that streamer emits intensely at Very High Frequency (VHF) band as it's already proven both theoretically and experimentally. A study by Cooray, theoretically proved that emission of electron avalanche peaks at microwave band. Air-gap parallel plate antenna which could operate at 1 GHz with remote sensing is designed and simulated to measure the microwave radiation emitted by lightning. Both temporal and wavelet analyses are used to compare the onset of microwave radiation and VHF radiation in both time and frequency domains to determine electron avalanche appears at which electromagnetic band.
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- Sabri, M. H. M., et al.
(author)
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VHF Emissions Prior to the Onset of Initial Electric Field Changes of Intracloud Flashes
- 2018
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In: 2018 INTERNATIONAL CONFERENCE ON ELECTRICAL ENGINEERING AND COMPUTER SCIENCE (ICECOS). - : IEEE. - 9781538657218 ; , s. 301-304
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Conference paper (peer-reviewed)abstract
- We present the observation of VHF impulses electric (E) field emissions found in two normal intracloud (IC) flashes accompanied by initial electric field changes (LECs) in a tropical thunderstorm. The data was collected on November 23rd, 2017 (within reversal distance) to our lightning sensor in Malacca, Malaysia. The durations from the onset of IECs to the first initial breakdown (IB) pulse are range between 0.68 and 0.69 ms and the magnitudes of IECs are range between 0.18 and 0.50 V/m. Besides that, before the onset of LECs there is small pulses was detected for IC flash (Nov_67) same with the VHF impulse for both IC flash. It was detected earlier before the onset of IEC by 12.69 and 251.60 mu s for the VHF impulse.
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- Seah, B. Y., et al.
(author)
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The Performance Evaluation of Capacitive Antenna with Various Structures and Permittivity Values
- 2018
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In: 2018 INTERNATIONAL CONFERENCE ON ELECTRICAL ENGINEERING AND COMPUTER SCIENCE (ICECOS). - : IEEE. - 9781538657218 ; , s. 457-460
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Conference paper (peer-reviewed)abstract
- This paper evaluates the capacitive antenna performance as a lightning sensor. The performance is evaluated by looking at two aspects, antenna structures and the background permittivity value of the antenna. Two experiments were carried out, Experiment A using two different structure antennas, one with its Bayonet Neill-Concelman (BNC) connector's core direct touching the top plate (DBNC) while the other was connected via single core wires (WBNC), capturing the electric field (E-field) generated by the small spark at a distance of 1 meter away from both antennas. Furthermore, both capacitive antennas with top plates directly soldered to their BNC cores were used to study their performance with and without being covered by plastic (dielectric constant of 2.25) during Experiment B. The result from Experiment A showed that WBNC has different onset polarity and significant decreased in amplitude of the signals captured compared to DBNC (mean ratio is 1.095 with range between 0.5838 and 4.528). Meanwhile, Experiment B shows that a comparable average ratio of 0.7835 and 0.7447 during the measurement where antenna A(wc) with and without the presence of plastic cover respectively.
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