In the context of energy harvesting for wireless sensor networks, the energy-harvesting system using the rectifying antenna (rectenna) has a great interest. Rectenna, which can convert RF energy to DC power, plays an important role for wireless power transmission (WPT) [1]. The typical rectenna in the prior literatures basically consists of five elements: receiving antenna, low pass filter (LPF) or harmonic rejection filter (HRF), diodes, DC pass capacitor and loading resistant [2], [3]. Recently, many rectennas have been reported, such as rectennas with various patch antennas [4], [5]. The circular polarization (CP) has become one of the important characteristic in rectenna design. The combination of harmonic rejection and CP properties would bring the advantages of low polarization loss, and improve the conversion efficiency. In this study, the rectenna based on a dual-circular polarized (DCP) patch antenna with coupling feed excitation is proposed, and it has ability to reject second harmonic noise. By etching the T-shape slot on the ground plane, the proposed DCP antenna can not only achieve CP operation, but also reject the second harmonic noise. Thus, the proposed rectenna can avoid the use of second harmonic rejection filter connecting to the antenna and rectifying diode. Besides, two feeding ports of the proposed antenna can be chosen to generate either left-hand circular polarization (LHCP) or right-hand circular polarization (RHCP).