(For USM Staff/Student Only)

EngLib USM > Ω School of Electrical & Electronic Engineering >

Very high frequency distilled water antenna

Very high frequency distilled water antenna / Muhammad Anwar Zulkifli
Kajian ini menumpukan kepada kajian antena air, sejenis antena cecair yang istimewa yang telah menarik banyak perhatian sejak kebelakangan ini Antena air ini menggunakan air suling sebagai medium dan beroperasi pada VHF dalam jaluran frekuensi. Antena air suling yang dicadangkan boleh menjadi alternatif kepada antena tradisional untuk pelbagai aplikasi terutamanya dalam bidang ketenteraan, sistem komunikasi marin dan komunikasi jarak dekat bagi pesawat. Objektif utama dalam kajian ini adalah untuk merekabentuk, membina dan menguji antena air suling VHF. Bekas antena air terdiri diperbuat daripada bahan PVC. Dua tiub PVC yang berlainan diameter digunakan dalam eksperimen ini. Spesifikasi tiub PVC adalah seperti berikut; ketinggian = 150 cm, ketebalan = 0.2 cm, diameter = 2.54 cm (1-inci) dan 5.08 cm (2-inci). Sekeping plat aluminium dengan spesifikasi 34 cm x 43 cm digunakan sebagai satah bumi. Rod tembaga sepanjang 1 m diletakkan secara kekal di dalam tiub PVC. Prestasi antena ini ditentukan dalam terma kekerapan salunan, kehilangan pulangan, lebar jalur, keuntungan dan corak radiasi. Ketinggian paras air diselaraskan dalam julat 0.25-1.5 m dengan jurang 0.25 m setiap satu. Kedua-dua antena air 1-inci dan 2-inci menunjukkan penurunan dari segi kekerapan salunan apabila paras air meningkat. Antena tersebut juga bergema dalam julat VHF bagi setiap paras air. Dapat dilihat juga bahawa jumlah isipadu air memberi kesan kepada kekerapan salunan antena air. Kehilangan pulangan yang diukur adalah semua di bawah -10 dB dan lebar jalur yang direkodkan adalah sekitar 8 - 20 MHz. Kedua-dua keuntungan dan corak radiasi diukur menggunakan frekuensi bernilai 85.362 MHz. Dua antena monopol digunakan sebagai antena rujukan semasa pengukuran keuntungan. Selepas pengiraan, keuntungan bagi antena air telah dikenalpasti iaitu dengan nilai 1.915 dB. Antena air mempunyai lebar jalur yang lebih lebar dan kehilangan pulangan yang lebih baik berbanding antena rujukan monopol. Untuk analisis corak radiasi pula, antena air 1-inci mempunyai penerimaan kuasa yang paling tinggi sebanyak - 17.82 dBm pada 280˚ dengan mengunakan 0.25 m air suling. Manakala bagi antena air 2-inci pula, penerimaan kuasa yang paling tinggi ialah -17.17 dBm pada 20˚ dengan mengunakan 0.5 m air suling. Secara keseluruhannya, iamya dapat disimpulkan bahawa antena air suling VHF menunjukkan prestasi yang baik dengan kekerapan saluran yang tinggi, kehilangan pulangan yg baik dan lebar jalur yang lebar. _______________________________________________________________________________________________________ This research is focused on the study of water antennas, a type special type of liquid antenna that has drawn a lot of attentions recently. The water antenna utilized distilled water as the medium and operate within the VHF band. The proposed distilled water antenna can be an alternative to traditional antenna for many applications especially in a military field, marine communication system, and aircraft short range communication. The main objective of this research is to design, fabricate and test a VHF distilled water antenna. The container of the water antenna is made up from a PVC material. Two different diameters of PVC tubes are used in the experiment. The specifications of the PVC tubes are; height = 150 cm, thickness = 0.2 cm, diameter = 2.54 cm (1-inch) and 5.08 cm (2-inch). An aluminium plate with a dimension of 34 cm x 43 cm is used as the ground plane. A 1 m brass rod is permanently placed inside the PVC tube. The performance of the antenna is determined in terms of resonant frequency, return loss, bandwidth, gain and the radiation pattern. The height of water level is adjusted within the range of 0.25-1.5 m with a 0.25 m gap each. Both 1-inch and 2-inch water antenna showed a decrease in terms of resonant frequency when the water level is increased. The antenna also resonated within the VHF range for each water level. It is also observed that the volume of water affects the resonant frequency of the water antenna. The return losses measured are all below -10 dB and the recorded bandwidth are around 8 -20 MHz. Both gain and radiation pattern are measured using a frequency of 85.362 MHz. Two monopole antennas are used as the reference antenna during the measurement of gain. After calculation, the gain of the water antenna has been identified with a value of 1.915 dB. The water antenna also has the wider bandwidth and a better return loss compared to the reference monopole antenna. For the analysis of radiation pattern, the 1-inch water antenna has the highest received power of -17.82 dBm at 280˚ using 0.25 m distilled water. While for 2-inch water antenna, the highest received power is -17.17 dBm at 20˚ using 0.5 m distilled water. Overall, it can be concluded that the VHF distilled water antenna shows a good performance with high resonant frequency, good return loss and a wide bandwidth.
Contributor(s):
Muhammad Anwar Zulkifli - Author
Primary Item Type:
Final Year Project
Identifiers:
Accession Number : 875007697
Language:
English
Subject Keywords:
water antennas; liquid antenna; distilled water
First presented to the public:
6/1/2018
Original Publication Date:
8/10/2018
Previously Published By:
Universiti Sains Malaysia
Place Of Publication:
School of Electrical & Electronic Engineering
Citation:
Extents:
Number of Pages - 95
License Grantor / Date Granted:
  / ( View License )
Date Deposited
2018-08-13 17:23:58.597
Date Last Updated
2019-01-07 11:24:32.9118
Submitter:
Mohd Jasnizam Mohd Salleh

All Versions

Thumbnail Name Version Created Date
Very high frequency distilled water antenna1 2018-08-13 17:23:58.597