The paper describes about multiband antenna which is suitable for various applications like Bluetooth, WiMax and WLAN. This antenna is designed to operate in three different frequency bands 2.4/5.2/5.8-GHz for WLAN and 2.5/3.5/5.5-GHz for WiMAX. It is basically a microstrip-fed antenna which mainly consist of three different structures i.e. pentagonal ring, V-shaped strip, and a defected ground plane. By adding V-shaped strip in the pentagonal ring, the antenna excites in two resonant modes without increasing the size of structure. As we include the defected ground plane which consists of isosceles triangular defect, our third band with improved impedance matching was obtained. © 2016 IEEE.