Mass Sensitivity Optimization of a Surface Acoustic Wave Sensor Incorporating a Resonator Configuration
"> Figure 1
<p>The schematic of a two-port R-SAW resonator with three IDTs.</p> "> Figure 2
<p>The schematic of the COM model for typical resonator configuration.</p> "> Figure 3
<p>The schematic of the periodic electrodes covering a piezoelectric substrate model.</p> "> Figure 4
<p>Meshed periodic structure in <a href="#sensors-16-00562-f003" class="html-fig">Figure 3</a>.</p> "> Figure 5
<p>Displacement profiles of periodic shorted-grating on ST-X Quartz: (<b>a</b>) eigenfrequency <span class="html-italic">f</span><sub>sc−</sub> = 312.539 (MHz); (<b>b</b>) eigenfrequency <span class="html-italic">f</span><sub>sc+</sub> = 314.528 (MHz).</p> "> Figure 6
<p>Input admittance of periodic IDT on ST-X quartz.</p> "> Figure 7
<p>Input admittance of periodic IDT on ST-2°X quartz: the red dashed box area shows the counteracted extrema in <a href="#sensors-16-00562-f006" class="html-fig">Figure 6</a>.</p> "> Figure 8
<p>The schematic of a layered periodic model with embedded electrodes.</p> "> Figure 9
<p>Displacement profiles of periodic layered shorted-grating on ST-X quartz: (<b>a</b>) eigenfrequency <span class="html-italic">f′</span><sub>sc−</sub> = 311.666 (MHz); (<b>b</b>) eigenfrequency <span class="html-italic">f′</span><sub>sc+</sub> = 312.466 (MHz).</p> "> Figure 10
<p>Input admittance of periodic layered IDT on ST-X quartz.</p> "> Figure 11
<p>The schematic of the <span class="html-italic">P</span>-matrix in the IDT section.</p> "> Figure 12
<p>The schematic of <span class="html-italic">P</span>-matrix in IDT section.</p> "> Figure 13
<p>The schematic of mass deposited along the <span class="html-italic">x</span>-axis from A to F on the two-port SAW resonator.</p> "> Figure 14
<p>The frequency responses for non-loaded and different sensitive areas shown in <a href="#sensors-16-00562-f013" class="html-fig">Figure 13</a> with mass loaded of the resonator.</p> "> Figure 15
<p>(<b>a</b>) The structure of the SAW resonator device; (<b>b</b>) the frequency response of the device.</p> "> Figure 16
<p>Measured frequency responses caused by (<b>a</b>) area B loaded and (<b>b</b>) area F loaded by SiO<sub>2</sub>.</p> "> Figure 17
<p>The simulated and measured mass sensitivity for different surface areas, each position being demonstrated by repeated measurements.</p> ">
Abstract
:1. Introduction
2. Theoretical Analysis
2.1. COM Equations for SAW Resonator
2.2. FEM Simulation of Periodic Structures
2.3. Frequency Responses of R-SAW Resonators
3. Technique Realization
3.1. R-SAW Resonator Preparation
3.2. Regional Mass Loading
4. Results and Discussion
5. Conclusions
Acknowledgments
Author Contributions
Conflicts of Interest
References
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Material | Density (kg/m3) | Elastic Stiffness Constant (1010 N/m2) | Piezoelectric Stress Constant (C/m2) | Dielectric Constant (10−12 F/m) |
---|---|---|---|---|
Quartz | 2651 | c11 = 8.674 | e11 = 0.171 | ε11 = 39.843 |
c12 = 0.699 | e14 = −0.0436 | ε33 = 40.7284 | ||
c13 = 1.191 | ||||
c14 = −1.791 | ||||
c33 = 10.72 | ||||
c44 = 5.794 | ||||
c66 = 3.9875 | ||||
Al | 2700 | c12 = 5.11 | ||
c44 = 2.63 |
Boundary | Mechanical Boundary Conditions | Electrical Boundary Conditions |
---|---|---|
ΓT (top of air) | Zero charge | |
ΓC (air-solid interfaces) | Free | Continuity |
ΓB (bottom of substrate) | Fixed | Ground |
ΓL, ΓR (left and right boundaries) | Periodic continuity boundary condition | |
ΓF, ΓE (front and back boundaries) | Periodic continuity boundary condition |
COM-Parameter | Value (without Mass Loading) | Value (with Mass Loading) |
---|---|---|
SAW Velocity (m/s) | 3149.1 | 3134.4 |
Normalized reflectivity κλ0 | −0.020 | −0.008 |
Normalized transduction coefficient α (Ω−1/2) | 2.573 × 10−5 | 2.186 × 10−5 |
Normalized static capacitance Cn (F/m) | 5.52 × 10−11 | 5.74 × 10−11 |
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Hao, W.; Liu, J.; Liu, M.; Liang, Y.; He, S. Mass Sensitivity Optimization of a Surface Acoustic Wave Sensor Incorporating a Resonator Configuration. Sensors 2016, 16, 562. https://doi.org/10.3390/s16040562
Hao W, Liu J, Liu M, Liang Y, He S. Mass Sensitivity Optimization of a Surface Acoustic Wave Sensor Incorporating a Resonator Configuration. Sensors. 2016; 16(4):562. https://doi.org/10.3390/s16040562
Chicago/Turabian StyleHao, Wenchang, Jiuling Liu, Minghua Liu, Yong Liang, and Shitang He. 2016. "Mass Sensitivity Optimization of a Surface Acoustic Wave Sensor Incorporating a Resonator Configuration" Sensors 16, no. 4: 562. https://doi.org/10.3390/s16040562