Wireless Passive Sensors for Remote Sensing of Temperature on Aerospace Platforms (original) (raw)

High temperature packaging for surface acoustic wave transducers acting as passive wireless sensors

Sensors and Actuators A: Physical, 2015

Numerous developments have been dedicated these passed years to demonstrate the use of surface acoustic wave (SAW) devices as passive sensors probed through a wireless radio-frequency link. Giving access to physical parameter variations without embedded power supply, recent works have shown that SAW sensors can be used under harsh environments such as temperatures in excess of 300 o C and much more. The purpose of this paper is to present a new packaging process for SAW sensors operating under temperature environments up to 600 o C. The robustness of this packaging process is first validated at the above-mentioned temperature using a classical temperature probe via wired connection. The reliability of this process applied to differential SAW sensors then is demonstrated by wireless interrogation of a quartz-based SAW differential sensor from room temperature to 480 o C. The sensor operation has been validated for several tens of hours without major failure nor significant deviation, although the measurement distance dynamic range is observed to be dramatically reduced with operating on such a wide temperature range.

Wireless and Passive Sensors for High Temperature Measurements

2012

Surface acoustic waves have been studied for more than 50 years and are mainly used as passive components (resonators, frequency filters, sensors, etc.) for signal processing, and more specifically. As demonstrated by Bao et al, surface acoustic wave devices can operate without on-board power supply using a dedicated interrogation unit. Using appropriate design considerations, these devices are sensitive to external conditions including temperature, pressure, strain or chemical/biological mass loading. Therefore, the unique characteristics of such devices allows for an effective implementation providing new opportunities for remote control of physical and chemical parameters.

Theory and application of passive SAW radio transponders as sensors

IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 2000

Surface acoustic wave (SAW) radio transponders make it possible to read identification codes or measurement values from a remote location. The decisive advantage of these SAW transponders lies in their passive operation (i.e., no power-supply), and in the possibility of wireless installation at particularly inaccessible locations. The passive SAW transponders are maintenance free.

State of the art in wireless sensing with surface acoustic waves

IEEE Transactions on Industrial Electronics, 2001

Surface acoustic wave (SAW) passive devices can be used in novel applications such as wireless identification and sensing. For identification purposes, a SAW transponder picks up an electromagnetic request signal and stores it until all echoes caused by multipath propagation have died away. Then, a characteristic response is beamed back to the receiver. In radio-link sensors, a physical or chemical quantity influences the propagation properties of the SAW and consequently changes the response pattern of the device. This paper surveys the operating principle of such sensors and their state-of-the-art performance. Examples include temperature sensors and sensors for mechatronic applications.

Passive wireless SAW sensors for IVHM

2008 IEEE International Frequency Control Symposium, 2008

NASA aeronautical programs require integrated vehicle health monitoring (IVHM) to ensure the safety of the crew and the vehicles. Future IVHM sensors need to be small, light weight, inexpensive, and wireless. Surface acoustic wave (SAW) technology meets all of these constraints. In addition it operates in harsh environments and over wide temperature ranges, and it is inherently radiation hardened. This paper presents a survey of research opportunities for universities and industry to develop new sensors that address anticipated IVHM needs for aerospace vehicles. Potential applications of passive wireless SAW sensors from ground testing to high altitude aircraft operations are presented, along with some of the challenges and issues of the technology.

Wireless SAW based high-temperature measurement systems

The paper exemplifies the development of a surface acoustic wave (SAW) temperature measurement system, showing the advantages of wireless data transmission and passive sensor operation. It includes results of research on lithium niobate, langasite and gallium-orthophosphate, three piezoelectrica used as substrate crystals for the SAW devices. Critical parameters, limits and prospects of the materials as well as technological issues concerning the metallization and the lifetime of reflective SAW delay lines are discussed. The packaging and assembly of high temperature (HT) stable transponders is explained. A slot antenna, a patch antenna and a dipole antenna, thus providing maximum flexibility for the sensor geometry, are investigated. A phase matching algorithm, enhancing the measurement resolution by two orders of magnitude compared to a conventional peak detection algorithm, is described. A fully integrated SAW temperature sensor system is presented, basing on a frequency modulate...

SAW devices as wireless passive sensors

Surface acoustic wave (SAW) radio sensors make it possible to read measurement values from a remote location. The decisive advantage of these SAW sensors lies in their passive operation with no need for a separate power supply, and in the possibility of wireless installation at particularly inaccessible locations. The passive SAW sensors are maintenance free.

Remote sensing of physical parameters by means of passive surface acoustic wave devices (“ ID-TAG”)

A system for remote measurement of numerous physical quantities with passive sensors is presented. It consists of a radio frequency interrogator with evaluation electronics and a surface acoustic wave (SAW) device used as a sensor. For practical tests, an interrogator has been developed, which is able to read commercial identification SAW-tags. As an example, the relative position and temperature of the SAW element have been derived from the received data. The temperature resolution proved to be about 0.1 "C within a range of -20 "C to +140 "C, the distance resolution is about 5 millimeters. The detection distance is up to 15 meters for 5 watts output peak power. The promising results indicate that using this technique remote sensing of many physical parameters is feasible. The sensors are wireless and do not require a power supply, so measurements in dangerous, radioactive or dirty environment or from moving or rotating objects becomes obtainable.

Self Contained Surface Acoustic Wave Temperature Sensor

Frequenz, 2001

A novel self-contained surface acoustic wave (SAW) temperature sensor is Introduced. The sensor's device is completely passive and operates with no battery or wiring. In contrast to conventional SAW sensor systems, this sensor type does not reflect radar queries but generates its own RF signals to transmit ID-code and sensor information to a sensor base station. Trie striking feature of the novel sensor element is that the energy needed for sensing and signal generation is provided by the temperature change of the sensed process itself. Efficient energy conversion is obtained by using a pyroelectric crystal in combination with a spark gap. The generated RF power is sufficient to obtain readout distances up to 200 m. The temperature measurement accuracy is better than 1 °K for a range from-20 °C to +150 °C even without sensor calibration. The mentioned features of the novel sensor allow numerous innovative applications in the industrial, automotive or household area. Übersicht Im vorliegenden Beitrag werden neuartige, vollständig autarke Oberflächenwellen-Temperatursensorelemente, die drahtlos und ohne Batterie arbeiten, vorgestellt. Im Gegensatz zu konventionellen Oberflächenwellensensoren, die nach dem Radarprinzip abgefragt werden, erzeugen die neuartigen Elemente selbständig ein Meßsignal aus der Energie des zu servierenden Prozesses. Mit diesem autark erzeugten Hochfrequenzsignal werden die Sensorinformation und gegebenfalls ein Identifikationskode per Funk zu einer Basisstation übertragen. Die Wandlung von Thermischer Energie in Hochfrequenzenergie erfolgt mit einem pyroelektrischen Element, dessen Ladung über eine Funkenstrecke impulsartig abgegriffen wird. Dieses Wandlungskonzept ist so effizient, daß Übertragungsreichweiten von bis zu 200 m erreicht werden können. Die Temperaturmeßgenauigkeit ist in einem Meßbereich von-20 °C to +150 °C, auch ohne Kalibrierung, genauer als 1 "K. Das völlig neuartige Sensorkonzept bietet eine Vielzahl von Anwendungsmöglichkeiten jm Industrie,-Haushalts-oder Automobilbereich.