Design of a compact rectenna for wireless power transmission miniaturization applications

This article proposes a compact rectenna for wireless power transmission (WPT) miniaturization applications. A specific rectenna design for powering a wearable optical stimulator is presented. As a critical factor, the required size of the rectenna should be within 1.5 x 1.5 x 1 cm(3). The rectenna is formed by an antenna and a rectifying circuit, which are designed separately and then integrated together. In order to make full use of the limited size, a loop antenna is utilized in this design and the rectifying circuit part is positioned inside the loop. In addition, to further miniaturize the design, the rectifying circuit is directly matched to the antenna without using of the matching circuit. After fabrication, the rectenna is first linked to a resistive load to test its capability of output DC power. Then, the rectenna is connected to a super-capacitor to store the converted DC power. During the measurements, a standard horn antenna is used to transmit the incident wave to the rectenna. It shows that with proper power input to the transmitting horn antenna, the performed voltage and harvested power of the rectenna can satisfy the design requirements.