Impedance loaded SAW sensors offer a wide range of measurement opportunities

Steindl, R.; Pohl, A.; Seifert, F.

doi:10.1109/22.809016

Cited by 34 publications

(19 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Here, the electrical energy is transformed into acoustic/mechanical energy. The latter is sent out by the IDT and propagates along the substrate, while the impedance is used as the sensor signal [ 29 , 30 , 31 , 32 , 33 , 34 ].…”

Section: Resultsmentioning

confidence: 99%

“…The latter is typically associated with high-Q resonators with reflectors defining a resonant cavity [ 28 ] where the resonance frequency is used as a measurement signal. Otherwise, also for sensing purposes, 1-port approaches have been designed with an SAW generating IDTs and metallic acoustic reflectors in a distinct distance as sensor elements [ 29 , 30 , 31 , 32 , 33 ], known as a 1-port SAW delay line (DL) [ 34 ]. Here, the IDT acts as an antenna and the change in the propagation characteristic of the reflected SAW is monitored.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Single Interdigital Transducer Approach for Gravimetrical SAW Sensor Applications in Liquid Environments

Nguyen

Kaulen

Simon

et al. 2017

Sensors

View full text Add to dashboard Cite

Surface acoustic wave (SAW) devices are well known for mass-sensitive sensor applications. In biosensing applications, chemical and biochemically evoked binding processes on surfaces are detected in liquid environments using delay line or resonator sensor configurations, preferably in combination with the appropriate microfluidic devices. All configurations share the common feature of analyzing the transmission characteristic of the propagating SAW. In this paper, a novel SAW-based impedance sensor type is introduced which uses only one interdigital transducer (IDT), simultaneously as the SAW generator and the sensor element. Here, the input port reflection coefficient S11 is measured at the IDT instead of the commonly used S21 transmission forward gain parameter. Thus, a sharp and distinct peak of the S11 spectrum is obtained, enabling a comfortable direct readout of the sensor signal. Proof of the concept was gained by analyzing the specific binding of the 4-mercaptophenylacetic acid gold nanoparticles (MPA–AuNP) directly to the IDT surface. The corresponding binding kinetic of the MPA–AuNP on the functionalized gold surface has been analyzed and a sensitivity of 7.4 mΩ nM−1 has been determined.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Single Interdigital Transducer Approach for Gravimetrical SAW Sensor Applications in Liquid Environments

Nguyen

Kaulen

Simon

et al. 2017

Sensors

View full text Add to dashboard Cite

show abstract

“…The change in permittivity is detected by an interdigital capacitor structure. Capacitive sensors are used in a wide range of sensing applications, for example non-destructive testing (NDT), chemical sensing, bio-sensing [16], humidity and moisture sensing [17], monitoring of curing processes [18], wireless sensing [19] and surface acoustic waves (SAW) [20]. An overview of the most important concepts related to interdigital electrode sensors are available in references [16,[21][22][23][24][25][26].…”

Section: Theorymentioning

confidence: 99%

Broad-Range Hydrogel-Based pH Sensor with Capacitive Readout Manufactured on a Flexible Substrate

et al. 2018

View full text Add to dashboard Cite

Environmental monitoring of land, water and air, is an area receiving greater attention because of human health and safety concerns. Monitoring the type of pollution and concentration levels is vital, so that appropriate contingency plans can be determined. To effectively monitor the environment, there is a need for new sensors and sensor systems that suits these type of measurements. However, the diversity of sensors suitable for low, battery powered-and large area sensor systems are limited. We have manufactured and characterized a flexible pH sensor using laser processing and blade coating techniques that is able to measure pH between 2.94 and 11.80. The sensor consists of an interdigital capacitance with a pH sensitive hydrogel coating. Thin sensors can reach 95% of their final value value within 3 min, and are stable after 4 min. Good repeatability was achieved in regard to cycling of the sensor with different pH and multiple measurements from dry state. We have also studied the relation between an interdigital capacitance penetration depth and hydrogels expansion. We believe that our passive sensor is suitable to be used in low power and large area sensor networks.

show abstract

“…SAW sensors could also be grouped into one-port SAW sensors and two-port SAW sensors which are also called impedance-loaded SAW sensors. One-port SAW sensors are directly affected by the measurand, impedance-loaded SAW sensors are electrically loaded by a conventional sensor, as a result, indirectly affected by the measurand [24][25][26]. In the impedance-loaded SAW sensors, the SAW device is used as a transponder for device identification, while the measurand is sensed by an external sensor.…”

Section: Introductionmentioning

confidence: 99%

An Impedance-Loaded Orthogonal Frequency-Coded SAW Sensor for Passive Wireless Sensor Networks

Dai

Fang

Zhang

et al. 2020

Sensors

View full text Add to dashboard Cite

A passive wireless impedance-loaded orthogonal frequency-coded (OFC) surface acoustic wave (SAW) sensor for wireless sensor networks was proposed in this paper. One of the chips on OFC SAW tag is connected to an external sensor, which could cause a phase shift in the time response of the corresponding part on the SAW device. The phase shift corresponds to the sensed quantity, which could be temperature, strain, vibration, pressure, etc. The OFC SAW tag is isolated by a proper package from the direct effect of the measurand on the device’s response which could avoid the multiple measurands coupling. The simultaneous work of multiple sensors is guaranteed by orthogonal frequency coding. By processing the response based on an extended matched filter algorithm, sensing information of the specific coded OFC device can be extracted from the superimposed response of multiple independent encoded sensors. Compared to previous methods, the proposed method can produce a more flexible passive (battery-free) wireless sensor suitable for large-scale wireless sensor networks. Simulation and experimental results demonstrate the effectiveness of the sensor.

show abstract

Impedance loaded SAW sensors offer a wide range of measurement opportunities

Cited by 34 publications

References 2 publications

Single Interdigital Transducer Approach for Gravimetrical SAW Sensor Applications in Liquid Environments

Single Interdigital Transducer Approach for Gravimetrical SAW Sensor Applications in Liquid Environments

Broad-Range Hydrogel-Based pH Sensor with Capacitive Readout Manufactured on a Flexible Substrate

An Impedance-Loaded Orthogonal Frequency-Coded SAW Sensor for Passive Wireless Sensor Networks

Contact Info

Product

Resources

About