This paper presents the design of rectenna for RF energy harvesting system. The resonance frequency of the different parts of the rectenna such as the antenna and rectifier circuit is 2.45 GHz. The Microstrip patch antenna was designed using commercially available CST software. The patch antenna was then fabricated and tested using Network Analyzer. In order to achieve for DC output voltage-boosting; an input power level of 10 dBm was used to the patch antenna. The best value of load resistance to harvest maximum output DC power was obtained through CST simulation. Finally, the received RF power, the values of output DC voltage and power were measured.