SAW sensors using orthogonal frequency coding

Puccio, D.; Malocha, D.C.; Gallagher, D.R.; Hines, J.H.

doi:10.1109/freq.2004.1418470

Cited by 41 publications

(22 citation statements)

References 6 publications

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“…Orthogonal frequency coding (OFC) [25][26][27] is a scheme used to encode the identity of a SAW temperature sensor using both time and frequency domain diversity. The bandwidth and time diversity, using adaptive correlation techniques, provide advantages for pulse compression and increased processing gain [28,29], which increases accuracy and precision over other approaches.…”

Section: Passive Wireless Saw Temperature Sensor Systemmentioning

confidence: 99%

Concrete temperature monitoring using passive wireless surface acoustic wave sensor system

Kim

Luis

Smith

et al. 2015

Sensors and Actuators A: Physical

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Section: Passive Wireless Saw Temperature Sensor Systemmentioning

confidence: 99%

Concrete temperature monitoring using passive wireless surface acoustic wave sensor system

Kim

Luis

Smith

et al. 2015

Sensors and Actuators A: Physical

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“…The frequency orthogonality makes chips transparent to chips of differing frequency, since the chip reflector peak frequency response is at the null of all other differing chips. [2] This is a key characteristic for the OFC SAW implementation. The OFC condition also yields enhanced time domain cross correlation properties.…”

Section: Chip Reflector Orthogonalitymentioning

confidence: 99%

“…A typical CDMA SAW RFID tag has 30+ dB loss, while a OFC SAW tag could have a range of 6-15 dB loss [2,3,4]. If the device is used with a unidirectional transducer, theoretically zero loss is achievable.…”

Section: Introductionmentioning

confidence: 98%

“…[1,2] The OFC SAW technology approach has been funded by NASA for possible inclusion in ground, space flight and space exploration sensor applications. In general, SAW technology has advantages over possible competing technologies: passive, wireless, radiation hard, operation from cryogenic to furnace temperature ranges, small, rugged, variable frequency and bandwidth operation, encoding and commercially available.…”

mentioning

confidence: 99%

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Orthogonal frequency coded SAW sensors and RFID design principles

Malocha

Pavlina

Gallagher

et al. 2008

2008 IEEE International Frequency Control Symposium

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Orthogonal frequency coded (OFC) SAW reflectors and transducers have been recently introduced for use in communication, sensor and RFID tag applications. [1,2] The OFC SAW technology approach has been funded by NASA for possible inclusion in ground, space flight and space exploration sensor applications. In general, SAW technology has advantages over possible competing technologies: passive, wireless, radiation hard, operation from cryogenic to furnace temperature ranges, small, rugged, variable frequency and bandwidth operation, encoding and commercially available. SAW sensor embodiments can provide onboard device sensor integration, or can provide integration with an external sensor that uses the SAW device for encoding the sensor information and transmission to the receiver. SAW OFC device technology can provide RFID tags and sensors with low loss, large operating temperatures and a multi-use sensor platform. This paper will discuss the key parameters for OFC device design, which include reflector and transducer design, coding diversity approaches, and insertion loss considerations. Examples of several OFC device sensors and RFID tags will be presented to show the current state-of-the-art performance for several NASA applications, as well as projections for future sensor and RFID tag platform performance.I.

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“…After reviewing the basic principles underpinning the production of a SAW wave using an IDT (and reviewing others attempts and ideas [11] - [15]), the model can now be constructed. Because the calculations of the acoustic wave are numerically and mathematically complex, a number of assumptions were assumed to simplify the device model.…”

Section: Model Assumptionsmentioning

confidence: 99%

Improving the security and actuation of wireless controlled microvalve

et al. 2006

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A wireless microvalve would have a wide range of applications, including biomedical applications such as fertility control and nano-litre drug delivery. Arguably the most important aspect for such a device is a secure method to actuate the valve, such that it is not actuated through the spectrum of electromagnetic radiation already present in the surrounding environment. Additionally, many of the possible applications are sensitive to electromagnetic (EM) radiation so the device should be designed to only require the minimum amount of EM input to actuate the valve. To overcome this problem, we propose the use of a coded interdigital transducer (IDT) to respond only to a coded signal. For the wireless microvalve to be useful in biomedical applications, the IDT's response to a specifically coded RF signal must be much greater than its response to another coded RF signal, even if the two codes are very similar, i.e. improve the signal ratio of the device. In this research we demonstrate a number of code sequences that have a correlation function such that the peak response is unique and can be used to provide a high signal-to-noise ratio (SNR) surface acoustic wave. That results in a unique activation of the device when the interrogating RF signal code sequence matches the stored code sequence in the device. Also we will investigate the trade-off between the needed code length to ensure secure operation and the area constrain of the device within the context of biomedical application. For this purpose, the IDT is modelled as a pulse compression filter, which correlates the input signal with a stored replica.Keywords: microvalve, SAW, IDT, biomedical applications, coded actuators INTORDUCTIONA wireless, battery less microvalve uses no direct electrical power but makes use of the interrogating signal to provide the needed actuation. Such a device can be placed in an inaccessible location thus opening up new host of applications such as flow regulation, on/off switching and sealing of liquids, gases or vacuums [1][2][3]. For this purpose we utilise an IDT configuration with the SAW device. The IDT transforms this incoming RF signal from the antenna to a SAW and vice versa. Wireless interrogation of the device is possible by connecting the IDT to an antenna. The SAW generated by the IDT propagates along the piezoelectric substrate. The principles of SAW and the SAW generation mechanism in the microvalve are discussed in a previous publication [3]. The high energy density and small size make SAW devices attractive for actuator applications. But on the other hand the device requires a high input power level to drive it, hence it is important to have an efficient antenna design and ensure that the device will only trigger to a uniquely coded RF signal. Both of these objectives can be achieved by modelling the IDT as a pulse compression filter thus combining the narrowband, high Q-factor operation of a band pass filter with a coded reception scheme. The coding gain further improves the Q-factor [4]. Since the wirel...

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SAW sensors using orthogonal frequency coding

Cited by 41 publications

References 6 publications

Concrete temperature monitoring using passive wireless surface acoustic wave sensor system

Concrete temperature monitoring using passive wireless surface acoustic wave sensor system

Orthogonal frequency coded SAW sensors and RFID design principles

Improving the security and actuation of wireless controlled microvalve

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