Wireless grid to realize battery-less sensor networks in indoor environments

This paper presents a new concept of wireless grid to realize battery-less sensor networks in indoor environments. In this environment, multiple wireless energy transmitters are distributed on the ceiling, and activate battery-less sensors located anywhere in the field. Carrier shift diversity is introduced to remove huge received power attenuation due to mutual interference between the target received signals having the same frequency. Moreover, antenna directivity is optimized under consideration of polarization. This paper demonstrates the concept of wireless grid by using prototype hardwares of wireless energy transmitters and battery-less sensors. Moreover, ray-tracing simulation of the target field validates the effectiveness of the proposed multi-point wireless energy transmission to realize uniform coverage of energy supply in 2-D space.