M.Sc. Engg.
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Item Design of a Novel Electromagnetic Bandgap Structure Assisted Phased Array Antenna(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh, 2008-08) Nahid, Elora; Mollah, Prof Dr. Md. NurunnabiWith the emergence of novel wireless technologies, the demands for larger bandwidth, high efficiency and high capacity RF and microwave devices have been growing tremendously. Electromagnetic bandgap structures (EBGSs) are such new materials which have been emerging P as potential means of improving the performance of existing RF active and passive devices. EBGS exhibits distinct passband and stopband characteristics. The thesis concerns the planar EBG structures in the form of conventional square patterned, dumbbell shape square patterned with one narrow slot, dumbbell shape square patterned with two narrow slots to design a novel phased array antenna. A 4 by 1 array is designed as a reference array. Feed network has been designed by 50 ohm and X/4 transmission line. An inset feed patch antenna is designed as antenna element. The EBGS is used under the feed line to steer the beam. This is a novel scheme to design an EBGS assisted phased array antenna. A 4 by 1 array assisted with conventional square patterned EBGS, dumbbell shape EBGS with one narrow slot in the center and dumbbell shape EBGS with two narrow slots at the extremes have been investigated theoretically. it is seen that square patterned EBGS assisted array with distribution of EBGS as 04-8-12 provides 100 beam steering. On the other hand dumbbell shape EBGS with one and two slots assisted same array provides 20° and 30° beam steering respectively. Thus dumbbell shape assisted phased array antenna provides more beam steering. Finally, it can be concluded that dumbbell shape EBGS with two slots provides more beam scanning capacity than that of dumbbell shape EBGS with one narrow slot.