This article presents the design, simulation and testing of an Ultra Wide Band (UWB) planar monopole antenna with WLAN band-notch characteristic. The proposed antenna consists, the combination of planar monopole antenna with partial ground and a pair of AMC structures. The AMC structure used for the design is mushroom-like. Design equation of EBG parameters is also proposed for FR4 substrate using transmission line model. Using proposed equations, Mushroom-like EBG structure is integrated along the feed line of a monopole antenna for WLAN (5 GHz-6 GHz) band rejection. The Current distribution and equivalent circuit model of antenna is used to explain band-notch characteristic of EBG resonator. The proposed antenna is fabricated on an FR4 substrate with a thickness of 1.6 mm and er = 4.4. The measured VSWR characteristic is less than 2 for complete UWB band except for WLAN band i.e. 5 GHz-6 GHz. The gain of the proposed structure is around 2 dBi-6.7 dBi for complete UWB band except for WLAN band where it is reduced to-4 dBi. The measured radiation pattern of proposed antenna is omnidirectional along H plane and bidirectional in E plane. A nearly constant group delay with variations < 2ns, except for the notched bandwidth makes proposed antenna suitable for UWB application.