This paper proposes, a high gain, Fabry Perot cavity antenna with coplanar waveguide (CPW) fed ultra wide band (UWB) radiating element. The proposed antenna has flat edge arrow shape-based radiating element, which act as a main radiating element and responsible for UWB radiation. This UWB microstrip antenna is parasitically coupled with an array of square parasitic patches (PPs), which act as partially reflective surface. The square patches are fabricated at the bottom of inexpensive FR4 substrate and suspended in the air with the help of dielectric rods at 1.5λ0 height. High gain is obtained by resonating PPs at near close frequencies of 3.8–8.8 GHz UWB, where partially reflective surface gives almost positive reflection phase gradients. Two laboratory prototypes of antenna, one with and another without partially reflective surface are fabricated and tested. Details of the proposed antenna design and role of partially reflective surface in gain enhancement of planar CPW fed UWB antenna are described, and typical experimental results are presented and discussed.