This paper presents a simple design of open stub loaded rectangular microstrip antenna for multiband operation. Two open stubs of suitable dimensions are placed at two diagonally opposite corners on the rectangular radiating patch. The antenna operates between 3.555 to 8.66 GHz at five independent frequency bands with almost constant frequency ratio of 1.45. The proposed antenna exhibits broadside and linearly polarized radiation characteristics in its operating band and gives a peak gain of 1.43 dB. This technique also reduces the copper area of the patch by 8.84% when compared to the copper area of conventional patch designed for the same frequency. The experimental and simulated results are in good agreement with each other.