This Small Business Innovation Research Phase I research project addresses distributed structural integrity monitoring of infrastructure systems such as bridges and pipelines. The existing solutions for structural state sensing are expensive, labor intensive, non-scalable, and unreliable. The focus of this project is to determine the feasibility of an innovative, cost effective, non-intrusive, and scalable structural-state sensing technology known as Active RF Test (ART). The ART technology is based on the use of mechanically flexible patch-like wireless sensor devices that can be attached to distributed points of a structure. ART uses RF energy delivered from an in-network energy source to the sensors. Because the ART sensor patches will be battery-less, they will be durable and environment-friendly. The expected outcomes of this project are a novel battery-less power system for the ART patch sensors including a receive and rectifier antenna and a thin film super-capacitor as the energy storage medium, an energy-efficient wakeup scheduling scheme, in which the active duty cycles of the sensors are synchronized for correlated measurements, and a proof-of-concept prototype of a flexible ART patch sensor.<br/><br/>According to the National Bridge Inventory database, the US transportation infrastructure has 589,540 bridges, of which 68,571 are structurally deficient. The report also indicates that more than 80% of deficient bridges are more than 30 years old. Other infrastructures such as energy pipelines also suffer from aging. There are more than 2.3 million miles of domestic oil and gas pipelines, of which 30% are more than 50 years old. As demonstrated by the Minnesota bridge collapse of 2007, aging infrastructures poses a significant societal challenge. The unique features of the proposed ART technology ? easy installation, low cost, scalability, energy self sufficiency, and durability ? make it an ideal response to this challenging problem.<br/><br/>This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).