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V.A. Sankar Ponnapalli,P.V.Y. Jayasree 한국통신학회 2019 ICT Express Vol.5 No.1
Fractal arrays are repetitive-geometry-based smart arrays having impressive array factor properties. However, the performance of these arrays degrades owing to their large number of antenna elements at higher expansion levels. This research work presents the thinning of Sierpinski fractal arrays while keeping an applicable balance between all array factor properties by using two types of bounded binary-fractal-tapering techniques known as Sierpinski and Haferman carpet anti-diagonal tapering techniques. Approximately 22% to 50% of antenna elements are thinned in each successive iteration of the Sierpinski fractal array with the proposed tapering techniques.
Venkata Aditya Sankar Ponnapalli,Pappu Venkata Yasoda Jayasree 한국전자통신연구원 2016 ETRI Journal Vol.38 No.6
Fractal antenna arrays are geometry-based thinned arrays having multiband applications. The major challenge of these arrays is their large number of elements at higher expansion factors. This article presents the thinning of fractal antenna arrays while maintaining an appropriate balance between the side lobe level and beam width by using various quantized fractal distribution functions. A 2D square fractal antenna array and 3DSierpinski gasket antenna array are considered in this article to validate the proposed distribution functions. Nearly one third of the antenna elements are thinned in each successive iteration except in the case of a one-count distribution function. The proposed technique can simplify practical implementation and exhibits better performance for various parameters such as the side lobe level, side lobe angle, and half power beam width than fully populated fractal antenna arrays.
Chemical Profile and Cytotoxicity Activity of Stem-bark of Anacardium occidentale
Shehu, Abdullahi,Ponnapalli, Mangala Gowri,Mahboob, Mohd,Prabhakar, Pitta Venkata,Olatunji, Gabriel Ademola The Korean Society of Pharmacognosy 2022 Natural Product Sciences Vol.28 No.2
Column chromatographic fractionation of the methanol and ethyl acetate extracts of the stem-bark of Anacardium occidentale led to the isolation of five compounds (1-5). Their structures were determined by spectroscopic means by comparing spectral data to be β-sitosterol (1), 2,4-dihydroxy acetophenone (2), 1-monolinolein (3), ethyl oleate (4) and β-sitosterol-3-O-β-D-glucopyranoside (5). These compounds were evaluated for cytotoxicity against human cancer cell lines: A549, SCOV3 and rat normal cell line NRK49f. Compounds 2-5 were for the first time isolated from A. occidentale.