Traditionally, sensor systems are considered independent systems that are separately designed, manufactured, and integrated into a target system such as an aircraft. In most cases, this is a complex and costly process including sensor design, installation, wiring, testing, and maintenance. The sensor size, installation method, wiring, and cost limit the sensor node in very limited numbers and positions. Moreover, because of limitations, there are many places where the sensor system cannot reach.

This innovation is a new technology to construct a sensor system composed of the same components/parts that are already in the target system without adding an extra independent sensor system, or making any significant change to the target system. The sensor system is transparent to the target system. The term ubiquitous means that the sensor and sensor network can reach places impossible for traditional sensing technologies to reach. This technology can more thoroughly monitor the system, reducing sensor system complexity and cost. Its application on aircraft and other systems can significantly improve the aircraft safety with minor hardware change and minor extra cost.

Current wireless sensor networks have some limitations: (1) The sensor node is complex and costly, having transmitter, receiver, control logic, battery, and others in one unit; (2) the interrogation distance is limited by the power attenuation in the space; and (3) a broadcasted EM wave increases the EMI hazards to the sensing environments. These limitations set a threshold for the sensor network applications. The tradeoff among distance, sensor size, robustness, cost, and EMI holds the gate that prevents wider sensor network adoption.

The new technology breaks those limitations by its unique advantages. This technology reduces power consumption in each sensor node because the sensor signal is transmitted for a very short distance (near field).

The LC resonant type wireless passive sensor node can be very robust, light, small in size, and low cost by eliminating many parts like the battery unit. Since the wireless signal is limited in the small distance of the near field coupling, no strong EM wave is broadcasting into space. The system can be applied without any mechanical change to the sensing environments. Building a sensor network is as easy as attaching the sensor nodes (either small units or an LC resonant tag).

This work was done by Stanley Woodard of Langley Research Center and Chuatong Wang of the National Institute of Aerospace. For more information, contact Langley Research Center at This email address is being protected from spambots. You need JavaScript enabled to view it.. Refer to LAR-18070-1.

NASA Tech Briefs Magazine

This article first appeared in the January, 2016 issue of NASA Tech Briefs Magazine.

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