A triple-band highly miniaturized antenna for WiMAX/WLAN applications

A novel highly miniaturized triple band antenna for WiMAX and WLAN applications is presented in this letter. The proposed design has an active patch area of only 108 mm(2) (9 x 12 mm(2)), and operates at 2.5 (lower WiMAX), 3.47 (middle WiMAX) and 5.75 GHz (WLAN), respectively. Miniaturization in the proposed design is accomplished by etching 2 novel cascaded E-type unit cell defected ground structure in conjunction with the F-shaped slot, and multiband operations are achieved by etching U and H-type slots in the radiating monopole. The miniaturization process leads to the reduction of about 82.4% and 73.5% in the active patch area and volume of the proposed antenna respectively, as compared with the conventional designed triple band antenna. The antenna has a compact volume of 0.15 lambda(0) x 0.15 lambda(0) x 0.01 lambda(0) at a lower resonance of 2.6 GHz. The proposed structure has S-11<-10 dB bandwidth of about 6.45% (2.55-2.72 GHz), 3.03% (3.25-3.35 GHz) and 5.9% (5.75-6.1 GHz) in simulation, and about 4.2% (2.51-2.62 GHz), 2.31% (3.42-3.50 GHz), and 4.81% (5.68-5.96 GHz) under measurement, respectively. Stable radiation characteristics and good impedance matching are observed across the operational bandwidth of the proposed design.