Currently flexible electronics and other sensors that can't employ bulky batteries and need to operate with very low power typically can't communicate with other devices more than a few feet or meters away. This limits their practical use in applications ranging from medical monitoring and home sensing to smart cities and precision agriculture. For example, knee patches that capture range of motion in arthritic patients to patches that use sweat to detect fatigue in athletes or soldiers – hold great promise for collecting medically relevant data.
In another example, a long-range backscatter system by the University of Washington, which uses reflected radio signals to transmit data at extremely low power and low cost, achieved reliable coverage throughout 4800-square-foot house, an office area covering 41 rooms and a one-acre vegetable farm. The system is detailed in a paper that was presented at UbiComp 2017.