Passive Impedance-Loaded Surface Acoustic Wave (SAW) Sensor for Soil Condition Monitoring

2020 ◽  
Author(s):  
Jian Chu ◽  
Ioana Voiculescu ◽  
Ziqian Dong ◽  
Fang Li
Keyword(s):  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Condition Monitoring ◽  
Low Cost ◽  
Soil Condition ◽  
Nutrient Sensing ◽  
Soil Conditions ◽  
Large Area ◽  
Saw Sensor ◽  
Loaded Surface

Abstract This paper presents an innovative system to monitor the physical soil conditions needed for modern agriculture. The current technique to measure soil properties relies on taking samples from place to place and takes them for laboratory testing. To build up and monitor a data-based system for a large area, such a method is costly and time-consuming. This paper reported our recent work on the development of a passive impedance-loaded surface acoustic wave (SAW) sensor for a low-cost soil condition monitoring system. The SAW sensor will eventually be connected to an antenna and a impedance-based sensor for autonomous soil nutrient sensing. In this research, first, the coupling-of-modes (COM) analysis was performed to simulate the SAW device. The sensors were fabricated with E-beam lithography techniques and tested with different external load resistances. We investigated how the sensor signal changed with the external resistance loading. The experimental results were verified by comparing them with simulation results.

scholarly journals Modelling and Simulation using Finite Element Method of Surface Acoustic Wave Biosensor for Gas Detection Application

2021 ◽  
Vol 2071 (1) ◽  
pp. 012022
Author(s):  
A M Noor ◽  
A N Norali ◽  
Z Zakaria ◽  
M Mazalan ◽  
Y Wahab
Keyword(s):  
Numerical Simulation ◽  
Acoustic Wave ◽  
Resonance Frequency ◽  
Surface Acoustic Wave ◽  
High Frequency ◽  
Low Cost ◽  
Computational Modelling ◽  
Low Frequency ◽  
Gas Detection ◽  
Saw Sensor

Abstract A surface acoustic wave (SAW) sensor detects changes in physical properties such as mass and density on its surface. Compared to other types of sensors, SAW sensor have a good stability, high selectivity and sensitivity, fast response, and low-cost. On the other hand, to design and optimize a SAW biosensor requires a long process including time and cost using conventional methods. Therefore, numerical simulation and computational modelling are useful and efficiently conduct analysis for the SAW biosensor. In this paper, a numerical simulation technique is used to analyse the SAW device sensitivity for the application of gas detection. The SAW biosensor can detect very small mass loading by changing its sensor resonance frequency. The two-dimensional (2D) device model is based on a two-port SAW resonator with a gas sensing layer. We made two design of SAW biosensor device with frequency of 872 MHz and 1.74 GHz. A gas with vary concentration from 1 to 100 ppm were used to determine the change of the device resonance frequency. As a result, the high frequency (1.74 GHz) device, shows that the resonance frequency is shifted larger than to the low frequency (872 MHz) device. In addition, the high frequency device offers five times more sensitivity than the low frequency device. By changing the sensor design, the sensor characteristics such as sensitivity can be altered to meet certain sensing requirements. Numerical simulation provides advantages for sensor optimization and useful for nearly representing the real condition.

A high sensitivity wireless mass-loading surface acoustic wave DNA biosensor

2014 ◽  
Vol 28 (07) ◽  
pp. 1450056 ◽  
Author(s):  
Hua-Lin Cai ◽  
Yi Yang ◽  
Yi-Han Zhang ◽  
Chang-Jian Zhou ◽  
Cang-Ran Guo ◽  
...  
Keyword(s):  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Dna Sequences ◽  
Biological Treatment ◽  
High Performance ◽  
Processing System ◽  
High Sensitivity ◽  
Treatment Method ◽  
Saw Sensor ◽  
Target Dna

In this paper, a surface acoustic wave (SAW) biosensor with gold delay area on LiNbO 3 substrate detecting DNA sequences is proposed. By well-designed device parameters of the SAW sensor, it achieves a high performance for highly sensitive detection of target DNA. In addition, an effective biological treatment method for DNA immobilization and abundant experimental verification of the sensing effect have made it a reliable device in DNA detection. The loading mass of the probe and target DNA sequences is obtained from the frequency shifts, which are big enough in this work due to an effective biological treatment. The experimental results show that the biosensor has a high sensitivity of 1.2 pg/ml/Hz and high selectivity characteristic is also verified by the few responses of other substances. In combination with wireless transceiver, we develop a wireless receiving and processing system that can directly display the detection results.

Development of ball surface acoustic wave gas chromatograph for environmental monitoring in spacecraft and its application on the ground

2022 ◽  
Author(s):  
Takamitsu Iwaya ◽  
Shingo Akao ◽  
Kazushi Yamanaka ◽  
Tatsuhiro Okano ◽  
Nobuo Takeda ◽  
...  
Keyword(s):  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Stationary Phases ◽  
Micro Electro Mechanical System ◽  
Steel Plates ◽  
Gas Chromatograph ◽  
Site Analysis ◽  
Saw Sensor ◽  
Ball Surface ◽  
Brewing Process

Abstract For on-site analysis of surface materials on the moon, planets, and small bodies and for the monitoring of air quality in crewed spacecraft, we have developed a portable gas chromatograph (GC) equipped with a ball surface acoustic wave (SAW) sensor. In this study, we fabricated a 10 cm cube GC that implements the forward flush method using two metal micro-electro-mechanical-system (MEMS) columns coated with different stationary phases in microchannels fabricated by wet etching and diffusion bonding of stainless-steel plates. Using this GC, we succeeded in analyzing 10 kinds of gas within 10 min. In addition, for the application of the ball SAW GC on the ground, we also developed a palm-sized GC with a single metal capillary column and used it in the analysis of the headspace gas of sake. We showed that the ratio of peak areas differed among odorants depending on the brand and brewing process of sake.

Improved Performance of Surface Acoustic Wave Sensors by Plasma Treatments for Chemical Warfare Agents Monitoring

2020 ◽  
Vol 20 (11) ◽  
pp. 7145-7150 ◽  
Author(s):  
Eunhyun Kim ◽  
Jinuk Kim ◽  
Seonggyun Ha ◽  
Changsik Song ◽  
Joo-Hyung Kim
Keyword(s):  
Acoustic Wave ◽  
Plasma Treatment ◽  
Surface Acoustic Wave ◽  
Chemical Warfare Agents ◽  
Chemical Warfare ◽  
Saw Sensor ◽  
Warfare Agents ◽  
Improved Performance ◽  
Lift Off ◽  
Sensing Performance

The effects of a plasma treatment on the sensing performance of surface acoustic wave (SAW) sensors to detect chemical warfare agents (CWAs) were investigated. SAW sensors designed for an operating frequency of 250 MHz were fabricated using lift-off techniques followed by the deposition of a very thin thiourea (TU) layer as a sensing film on the sensing area of the SAW sensor. To achieve some advantages from the plasma treatment on the surface, such as cleaning, surface activation and modification, a post-plasma treatment was performed on the sensing layer and the sensing performance of the SAW sensor was measured by a comparison with the measured responses, providing different simulant gases through the gas feeding system. The sensitivity test revealed significant improvement in the sensing ability of the SAW sensor to detect DMMP, a simulant of a CWA, but with a relatively longer recovery time. The responses of other simulants at different concentrations and different simulant vapors were compared. The results showed that a plasma treatment on the sensing layer of a SAW device can improve the selectivity and sensitivity to a certain target gas or some volatile organic compounds. Therefore, a plasma treatment will be very useful for improving the selectivity and sensitivity of SAW sensors for the detection of CWAs.

scholarly journals Perturbation Analysis of a Multiple Layer Guided Love Wave Sensor in a Viscoelastic Environment

Sensors ◽  
2019 ◽  
Vol 19 (20) ◽  
pp. 4533 ◽  
Author(s):  
Tao Wang ◽  
Ryan Murphy ◽  
Jing Wang ◽  
Shyam S. Mohapatra ◽  
Subhra Mohapatra ◽  
...  
Keyword(s):  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Liquid Layer ◽  
Perturbation Analysis ◽  
Love Wave ◽  
Low Cost ◽  
Maxwell Model ◽  
Theoretical Models ◽  
Fast Response ◽  
Liquid Environment

Surface acoustic wave sensors have the advantage of fast response, low-cost, and wireless interfacing capability and they have been used in the medical analysis, material characterization, and other application fields that immerse the device under a liquid environment. The theoretical analysis of the single guided layer shear horizontal acoustic wave based on the perturbation theory has seen developments that span the past 20 years. However, multiple guided layer systems under a liquid environment have not been thoroughly analyzed by existing theoretical models. A dispersion equation previously derived from a system of three rigidly coupled elastic mass layers is extended and developed in this study with multiple guided layers to analyze how the liquid layer’s properties affect the device’s sensitivity. The combination of the multiple layers to optimize the sensitivity of an acoustic wave sensor is investigated in this study. The Maxwell model of viscoelasticity is applied to represent the liquid layer. A thorough analysis of the complex velocity due to the variations of the liquid layer’s properties and thickness is derived and discussed to optimize multilayer Surface acoustic wave (SAW) sensor design. Numerical simulation of the sensitivity with a liquid layer on top of two guided layers is investigated in this study as well. The parametric investigation was conducted by varying the thicknesses for the liquid layer and the guided layers. The effect of the liquid layer viscosity on the sensitivity of the design is also presented in this study. The two guided layer device can achieve higher sensitivity than the single guided layer counterpart in a liquid environment by optimizing the second guided layer thickness. This perturbation analysis is valuable for Love wave sensor optimization to detect the liquid biological samples and analytes.

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