Design of compact Dual-Band fractal antennas for WLAN/WiMAX applications

Abstract

In this project, a new design approach is presented for achieving a miniaturized dual-band microstrip patch antenna (MPA) suitable to be used for 2.4 GHz WLAN band, and 5.5 GHz WiMAX band. The first proposed antenna which is composed of a semi-circular radiating arm attached to four identical smaller semicircular arms to form a comb structure loaded with a horizontal rectangular stub with a 50- O transmission by feed line printed on the top side of an FR4 substrate. A tapered partial ground plane is printed on the back side of the substrate. The second proposed design is composed of three interconnected??- shaped arms feed with a 50 Ohm microstrip line on the top side of the FR-4 substrate and a tapered ground plane in its back side. A CST Microwave Studio (CST MWS) is used to model the designed antennas, and simulation results, in terms of reflection coefficient (S11), realized peak gain, efficiency and radiation patterns. To validate the design concept, the antenna designs are fabricated, the simulated and measured S11 results are nearly coincide with each other. The semi-circular comb antenna is characterized by miniaturized size of 24 × 29.5 ???? 2, and measured bandwidths of 600 MHz (2–2.6 GHz) and 2.6 GHz (5.4–8 GHz). The second proposed structure, triple ??- shaped patch, is characterized by compact size of 22 × 32 ???? 2, and measured bandwidths of 800 MHz (2–2.8GHz) and band 2.4 GHz (4-6.4 GHz ).