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Aru, O. E.
Department of Computer Engineering, Michael Okpara University of Agriculture, Umudike, Abia State, Nigeria
Okoye, A. C.
Department of Electrical/Electronic Engineering, Federal University of Technology, Owerri, Imo State, Nigeria.
ABSTRACT
Array antennas require a multiplier termed ‘Array Factor’ for easy computation of the array parameters. However, Log-Periodic Dipole Array antennas (LPDAs), which have varying amplitudes and spacing between elements, have no detailed numerical procedure for deriving a closed form Array-Factor for computing the array parameters unlike the Log-Periodic Circular Array (LPCA) antennas. This makes it difficult to establish the relationship between array factor of LPDA antennas and other array antennas such as the LPCA antennas. The work presented in this paper established a standard and detailed procedure for deriving a compact Array Factor for Log-Periodic Dipole Array antennas using the conventional Magnetic Vector Potential model. Log Periodic Dipole Antenna (LPDA) is used for the experimental process. It is assumed that the dipole elements have negligible diameters and as such, the current distributions of the center-fed elements are sinusoidal and hence vanishes at the end points of the dipoles. Through the use of analytical measures, the pattern for the array factor was determined numerically. The Log-Periodic Dipole Array antenna, the Cartesian plots and the polar plots of the results of the Array-Factors for different number of dipole elements (N=3, N=5, N=10, and N=15), when the design factor (DF) τ equals 0.95. The patterns show systematic increase in the number of side lobes as the number of the dipole element increases, and increase in the directivity of the main lobe in that order. As the angle of signal radiation decreases, the main lobe becomes more directive whereas the number of side lobes generated also increases. The analytical results obtained indicate that the array factor for LPDA antennas is the same with other LPA antennas. This forms the basis for the determination of the LPDA antenna parameters.
Keywords: Electromagnetic Waves, Frequency Independent Antennas, Log Periodic Dipole Array (LPDA) Antenna, Ultra Wide - Band (UWB), Wireless Communication, Array Factor
https://doi.org/10.33922/j.ujet_v10i1_16
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Published
Tuesday, April 23, 2024
Issue
Vol. 10 No. 1, June 2024
Article Section
GENERAL
The contents of the articles are the sole opinion of the author(s) and not of UJET.
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