This proposed work illustrates the design of a defected ground structure (DGS)-based coplanar waveguide (CPW)-fed multiband microstrip antenna consisting of four vertical monopoles, joined together by the few rectangular horizontal strips. In this multiband antenna, I-shaped defects are inserted into both sides of ground plane of CPW feed creating a DGS-CPW. The 10 dB impedance bandwidth of lower band is 29%, ranging from 2.232 to 3.1 GHz, with respect to the central frequency of 2.52 GHz, and while that of the upper band is 2.1 GHz (4.712–6.81 GHz), about 35%, referred to the central frequency of 5.7 GHz. The parametric study is performed to understand the characteristics of the proposed antenna. To verify the simulated design concept, a prototype antenna is designed and fabricated on the FR4 substrate, and characterized experimentally. The characteristic of antenna parameters such as S-parameter, gain, current distribution, and radiation pattern have been studied. The proposed antenna is suitable for WLAN/WiMAX applications.