Surface acoustic wave passive transponder having nonreflective transducers and pads

Skeie, Halvor

doi:10.1121/1.396305

Cited by 3 publications

(4 citation statements)

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“…As derived above, according to (6), the real response of a resonator to an RF sinusoidal burst has the form of , and , and the correlation of the response and a harmonic at null delay is (16) While is around , the integration is approaching null. As a result, the first item in (16) can be neglected, then …”

Section: Estimating the Resonant Frequency Of A Resonator Sensor Imentioning

confidence: 99%

“…Equation (15) implies that the envelope of the oscillation with a frequency to be estimated must be deterministically known, then a match filter can be constructed to get the statistical quantity. However, for the wireless sensing signal, while the interrogation is sinusoidal bursts, the sensing output as expressed in (6). Its envelope in the waveform is not fixed; it is varied with the difference between the interrogation and the resonant frequencies.…”

Section: Estimating the Resonant Frequency Of A Resonator Sensor Imentioning

confidence: 99%

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Detecting and Evaluating the Signals of Wirelessly Interrogational Passive SAW Resonator Sensors

Wen

Yang

et al. 2004

IEEE Sensors J.

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The wireless sensing signal of a passive surface acoustic wave (SAW) resonator sensor is the response of the SAW resonator in a passive circuit to wireless radio frequency interrogation. The response is produced only in the case that the interrogation covers the operational frequency band of the resonator. The wireless response is transient and can only be detectable in a proximity after switching off the interrogation. Due to the fact that, while used as a sensor, the resonant frequency of the resonator is related to and varying with the measurand, the interrogation to a passive SAW resonator sensor has to trace and follow the correspondent variation of the frequency band of the device. The energy evaluation of the response is applied to detect the availability of the sensing response and is used as a feedback argument to roughly localize the operational frequency range of the sensor. A modified frequency estimation is employed to estimate the sensing characteristic frequency in the transient wireless sensing signal with a low signal-to-noise ratio. The estimation is used to further adjust the interrogation frequency to follow the frequency variation of the sensor until the response becomes optimal. The evaluation of signal energy along with the statistical quantity of frequency estimation gives a reference for the confidence of the estimated frequency.Index Terms-Passive surface acoustic wave (SAW) sensor, sensing signal detection, sensor signal processing, wireless sensing.

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Section: Estimating the Resonant Frequency Of A Resonator Sensor Imentioning

confidence: 99%

Section: Estimating the Resonant Frequency Of A Resonator Sensor Imentioning

confidence: 99%

Detecting and Evaluating the Signals of Wirelessly Interrogational Passive SAW Resonator Sensors

Wen

Yang

et al. 2004

IEEE Sensors J.

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“…The two possibilities for the design of SAW-IDtags are reflective tags [4] (see fig.1) or, alternatively, tags consisting of several transducers connected together with a common busbar [l], [5]. The bus-bar connected transducer tag is very similar to the well known tapped delay line connected as a one port device.…”

Section: Basic Considerationsmentioning

confidence: 99%

Programmable reflectors for SAW-ID-tags

Reindl¹,

Ruile²

1993

1993 Proceedings IEEE Ultrasonics Symposium

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Abslract -Surface acoustic wave devices for identification systems (SAW-ID-tags or SAW wireless labels) have a large potential for future applications. We concentrate in this paper on reflective SAW-IDtags with amplitude modulation.We use splitfinger interdigital transducers as reflecting structures. If the transducers are short circuited or capacitivly loaded the reflection disappears almost entirely. On the other hand, if an open circuit or inductive load is used, the lDTs reflect incoming SAWS. The coding of the reflectors can therefore be done once and for all by a, e.g., photolithographic process or, alternatively, programmable by external circuitry. This new possibility of dynamic programming can be used to transmit time dependent data.We present basic considerations on the design and measurements of prototypes of SAW-ID-tags on YZ-LiNbOS at 285MHz and 2.45GHz.1051-0117/93/0000-0125 $4.00 0 1993 IEEE

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“…The delay time of the delay line SAW wireless transponder varies with physical or chemical parameters [9,10], such as the wireless monitoring for acceleration, strain and temperature [11][12][13]. Many similar patents are applied in different fields, such as the reflected SAW passive transponder [14,15], remote sensing [16,17], the recognition tag [18,19] and pipe identification [20]. In these sensors, the sensing signals of passive wireless SAW sensors come from responses to wireless RF interrogations.…”

Section: Introductionmentioning

confidence: 99%

Design and fabrication of passive wireless sensor array system using composite coding resonant SAW transducer

Wen

2006

Meas. Sci. Technol.

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This paper presents a novel composite SAW (surface acoustic wave) passive wireless sensor system involving a resonator and a delay line. While the interrogational signal is a sinusoidal burst, the response is a delayed and damped oscillation. The frequency and the delay time of response are related to the measurand and the coding of the sensor element, respectively. The composite sensor consists of a SAW resonator and a delay line. It combines the advantages of these two devices and can be used as elements of multiple sensors for longer distance passive wireless measurements. As the wireless sensing response is weak and transient, in order to get the response with the maximum signal-to-noise ratio, the interrogational frequency is designed to be adjustable according to the result of frequency estimation. As a result, an optimal sensing result is achieved. In the transceiver set-up, the software DDS (direct digital synthesis) source with a rather high resolution is implemented to track the passive wireless sensor. An isolated switch is set in transmitter to depress the correlation leakage noise after switching off the wireless RF (radio frequency) interrogation signal. In this paper, the characteristics of the response, the working procedure of the signal processing, sensor temperature test results and the system error analyses are elaborated. A prototype instrument is built. Experimental results show the effectiveness of the instrumentation and the advantages of the composite sensor system.

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Surface acoustic wave passive transponder having nonreflective transducers and pads

Cited by 3 publications

References 0 publications

Detecting and Evaluating the Signals of Wirelessly Interrogational Passive SAW Resonator Sensors

Detecting and Evaluating the Signals of Wirelessly Interrogational Passive SAW Resonator Sensors

Programmable reflectors for SAW-ID-tags

Design and fabrication of passive wireless sensor array system using composite coding resonant SAW transducer

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