Narrow bipolar pulses and associated microwave radiation

Ahmad, Mohd Riduan and Mohd Esa, Mona Riza and Cooray, Vernon (2013) Narrow bipolar pulses and associated microwave radiation. In: PIERS 2013, 12 - 15 August 2013, Stockholm, Sweden.


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Narrow Bipolar Pulses (NBPs) is a special type of intra-cloud lightning discharge activities. It is known with other names also such as Narrow Bipolar Events (NBEs), energetic intracloud events, and Compact Intracloud Discharges (CIDs). NBP signatures have been measured by using various methods such as broadband antenna systems, HF-VHF direct measurement systems (filter-detector receiver), and satellite- based systems. To the best of our knowledge, there are no attempts have been made to measure NBP signatures at microwave region so far. In this paper, observations of microwave radiation from thunderstorms have been made during the northeast monsoon season of 2012 in Malaysia. Broadband fast antenna system and wideband microwave receiver captured simultaneous records of NBPs electric field change and microwave radiation, respectively. The wideband microwave receiver consisted a Low Noise Amplifier (LNA) connected to a Band Pass Filter (BPF) with operating frequencies between 1.5 and 3 GHz. Electrical signals induced by the incident electric fields on a whip antenna with omni directional pattern (E-plane half power beam width 19 degrees and 9 dBi gain) were directed towards the LNA by using a 5 meters 50Ω RG58 coaxial cable. The output electrical signals of the BPF were digitized directly by an oscilloscope at a rate of 2.5 Giga Samples/second. An oscilloscope at a rate of 25 Mega Samples/second digitized the output of electrical signals from the broadband fast antenna system. Strong noise-like burst of microwave radiation pulses associated with NBP events were detected. The total duration of the microwave bursts of the pulses is in the range between 5 and 8 μs meanwhile the total duration of the NBP pulses is in the range between 10 to 25 μs. We will provide detail time- frequency analysis of both NBP and its associated microwave radiation by using wavelet transform method.

Item Type: Conference or Workshop Item (Paper)
Subjects: Q Science > QA Mathematics > QA75 Electronic computers. Computer science
Q Science > QC Physics
Divisions: Faculty of Electronics and Computer Engineering > Department of Computer Engineering
Depositing User: En. Mohd Riduan Ahmad
Date Deposited: 23 Dec 2013 03:45
Last Modified: 30 May 2023 16:30
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