RF POWER HARVESTING WITH MULTIPLE RECTENNA ELEMENTS FOR BATTERY-LESS RFID SYSTEMS

摘要

RF power harvesting enables controllable and simultaneous wireless power delivery to many RF devices. Devices built with this unique technology can be sealed, embedded within structures, or made mobile, thus eliminating additional service for battery. A key component of this technology is the "rectenna", which is composed of antennas and rectifying circuitry to convert RF energy into DC power. Typically, multiple antenna elements are used to produce sufficient power for reliable device operation. This paper compares two different rectenna architectures (see Fig.1) for maximum RF-to-DC power conversion efficiency due to non-linear characteristics of the rectifying circuitry. A simple rectenna design example containing a 2X2 planar antenna array will be presented to demonstrate such RF power harvesting technology. The quantity, Rectenna Topology Indicator (RTI), is introduced for performance comparison.