In this paper, a microstrip rectangular patch antenna (MRPA) with defect in ground in terms of reduction in dimension has been simulated, tested and analyze for multiband wireless applications. The defect (reduction in size) has been introduced to study the grounding effect in patch antennas for four configuration namely full ground, quarter ground, half ground right and half ground left antennas. After the comparison of simulated results of all four structures, the proposed better performed antenna with 23.815mm x 41 mm x 1.6mm dimension has been fabricated and tested. It operates in wide bandwidth from 2.5 GHz to 9.2 GHz suited for S band requirements which covers many wireless applications like Wifi, WLAN and WiMax. The experiment results shows that the proposed antenna has lower group delay and loss, ideal VSWR less than 1.5, impedance nearer to ideal 50 ohm and gain of 4.3 dBi. There is very good agreement between the simulated and tested results.