Gain enhancement of a dual-band WLAN microstrip antenna loaded with diagonal pattern metamaterials

This communication presents the gain enhancement of a dual-band WLAN microstrip antenna loaded with left-handed split-ring resonator metamaterials. A diagonal repeating pattern of metamaterial unit cells is integrated into the right corner of the substrate to enhance the gain in the lower WLAN band without distorting the upper band characteristics. The proposed antenna covers the different operating bands: 2.4-2.484 and 5.15-5.85GHz (IEEE 802.11a and b/g/n) for WLAN applications. The gain improvement in the lower operating band is obtained around 3.69dB which is explained by estimating the Green function of the metamaterial diagonal periodic pattern at the lower resonant frequency. The antenna provides high gain and efficiency and easily printable on a low-cost FR-4 substrate. The proposed antenna prototype is developed and tested and experimental results show an excellent agreement with the simulated one.