Sending power over a wireless network will be a reality really soon!
The lifelong dream from Nikola Tesla of Wireless electrical energy transmission (http://www.teslasociety.com/tesla_tower.htm) is closer to become a reality.
But, harvesting power from RF is a bad idea because of how much power is lost in transmission. instead, they should be harvesting existing power source like light. properly designed systems can be ultra-low power if designed correctly and run on millifarads a day. believe it or not, a solar cell harvesting indoor lighting is enough to power a microprocessor in real time though it would be better to have a MEMS sensor waking up the microprocessor to collect it's latest measurement. the real problem comes in reporting the data back to the hub because RF is a HUGE power hog. you can use it just fine but not very long, so you transmit your collected data and turn off the RF until the next scheduled broadcast.
