The effect of metallic nearby objects set challenges for multi-band antenna performance due to the behaviour of electromagnetic waves on conductive boundaries. In this paper, the effect of the metallic nearby object on the performance of a multi-band slotted microstrip antenna based on slot loading technique antenna is studied. Two U-shaped slots are inserted into the patch antenna to operate at different frequency band for wireless applications. The proposed antenna has advantages of compactness and multi-functionality. The antenna is designed, fabricated and measured. The performance is evaluated in terms of resonance frequencies, gain and radiation pattern, demonstrating the need to include analysis of multi-band antenna placement early in the design process.