Optimal Design of an Antenna Array for Energy Harvesting

A high-gain, linear polarized microstrip antenna array for energy harvesting at 915 MHz is studied in this letter. The optimization theory for wireless power transmission efficiency has been used to design the feeding network of the antenna array to achieve the maximum power transmission efficiency with a given antenna configuration. As a demonstration, a light emitting diode (LED) is used as the resistive load of the rectifier (a three-stage Dickson charge pump circuit) connected to the antenna array terminal. For a given input power of 10 dBm fed into a circularly polarized transmitting antenna with 6 dBi gain, the maximum distance for lighting the LED is 51 cm.