A Wireless Power Transmission System Based on Solar Power and Switched Beam for Charging Multiple Wireless Sensor Nodes

In the thesis, we propose a new far-field wireless power transmission system at 2.45 GHz ISM band, including a power source and energy harvesting circuits for wireless sensor nodes. To the best of our knowledge, no publish work has discussed the design that contains both RF power transmitter and receivers for WSNs in a solar based wireless power transmission system. By observing the regulations of Federal Communication Committee (FCC), we have implemented the system and suggested several parameter settings and selections of hardware for design. Moreover, in most RF harvesting scenarios, RF sources are not steady but solar power density is relatively high, so we make a combination of solar power and RF harvesting in our proposed system. Solar power is collected and then transformed into controllable RF power for transmission in four desired directions. As for wireless sensor nodes, the RF harvesting circuit is designed and implemented with about 20~30% RF-DC conversion efficiency, and a new charging logic is proposed as well. In summary, a whole-system scope of WPT technique is illustrated and can be a good example of the rechargeable WSNs design in the future.