Wireless energy transmission for structural health monitoring embedded sensor nodes

In this paper, we present a feasibility study of using wireless energy transmission systems to provide a required power for structural health monitoring (SHM) sensor nodes. The goal of this study is to develop SHM sensing systems which can be permanently embedded in the host structure and do not require an on-board power sources. With this approach, the energy will be periodically delivered as needed to operate the sensor node, as opposed to being harvested as in the conventional approaches. The wirelessly transmitted microwave energy is captured by a microstrip patch antenna, and then transformed into DC power by a rectifying circuit and stored in a storage medium to provide the required energy to the sensor and transmitter. Based on the fact that recent networked sensor systems require power on the order of fractions of a watt, it is quite possible to operate such sensing devices completely from the captured wirelessly delivered energy. The method of designing and optimizing a wireless energy transmission system is discussed. This paper also summarizes considerations needed to design such energy delivery systems, experimental procedures and results, and additional issues that can be used as guidelines for future investigations.