Metamaterial Loaded Compact Multiband Monopole Antenna for Wireless Applications

This paper proposes the design of a compact monopole antenna loaded with metamaterial (MTM), for multiband operation for wireless local area network (WLAN) and Worldwide Interoperability for Microwave Access (WiMAX) applications. The monopole antenna is originally designed to operate in 2.8 GHz and 6 GHz The placement of MTM yields one additional band at 3.5 GHz corresponding to WiMAX with a shift in fre-quency of the original monopole to the WLAN frequen-cies of 2.4 GHz and 5.5 GHz with improved matching at the higher band. Dependencies of resonant frequencies on various parameters are formulated through regression analysis and a design equation for the proposed antenna is developed. The full-wave simulation and design equa-tion of the three resonances show a negligible differ-ence. A comparative study of the developed monopole with reported antennas shows that the developed struc-ture is compact with an overall dimension of 19 x 31 mm2. The measured results of the antenna show good impedance bandwidth of 6.25%, 24.57%, and 16.54% for the three bands centered at 2.4, 3.5, and 5.5 GHz The antenna compactness is obtained due to metamate-rial loading. All the simulated radiation characteristics of the proposed antenna are validated experimentally. The proposed antenna obtains a compact electrical size of 0.248x0.152 lambda 02 at 2.4 GHz with multi-band operations at frequencies 2.4 GHz, 3.5 GHz, and 5.5 GHz corre-sponding to WLAN and WiMAX.