Measurement of the electric permittivity using Bleustein–Gulyaev wave sensor

Abstract

We present a novel compact electric permittivity sensor that exploits Bleustein-Gulyaev (BG) waves propagating along the surface of shear-poled piezoelectrics. We formulate the dynamic nonlinear electromechanical partial differential equations of motion governing wave propagation under electromagnetically quasistatic conditions. The permittivity of the medium-under-test was found to influence the sensor eigenvalues, enabling the implementation of a frequency-shift permittivity sensor. Solution of the equations of motion demonstrates resonance of the first and third modes when excited using an IDT. We fabricated two sensor prototypes on shear-poled PZT4 and LiNbO3 substrates and used a Vector Network Analyzer to observe the shift in their fundamental natural frequency in the presence of various media-under-test. S11 measurements show deterministic and repeatable shifts in the resonant frequency of the first mode of the LiNbO3 sensor measured at △f1=3.51 MHz for ethanol and △f1=7.49 MHz for deionized water where the bare surface frequency was initially at f1=25.27 MHz.

Built-In Packaging for Single Terminal Devices

“…To illustrate the proposed packaging method for an actuator application, a m onator needed to be designed, and this design should be compatible with the a and characterization setups, and easy to fabricate and package. First, the importa ria were specified and then associated with geometrical and material properties Though only a single-terminal actuator application is illustrated in this work, the proposed concept is valid for sensor applications (accelerometer [14], gyroscope [15], mass sensor [16], humidity sensor [17], temperature sensor [18], pressure sensor [19], gas sensor [20], water sensor [21], magnetometers [22], photoacoustic sensors [23], FET-biosensor [24], and permittivity sensor [25]), optical and photonic applications (micromirror [26], microswitch [27], LiDAR [28], beam steering [29], bolometer [30], photon detector [31], and PeCOD [32]), RF applications (diode [33], transistor [34], antennas [35], switch [36], phase shifter [37], filter [38], and tunable capacitor [39]), microfluidics (micropump [40], microdroplet generator [41], and microvalve [42]), and other applications (energy harvester [43], rectenna [44], gripper [45], etc. ).…”

Analysis of SAW Temperature Properties in KTiOPO4 Single Crystal

“…The pseudo-surface acoustic wave is similar to the Rayleigh wave because it has no transverse displacement component. BG waves, due to their high sensitivity to fluid viscosity, are of considerable interest for the use in biomedical applications [22][23][24][25][26]. For the BG wave propagation, the displacement of material particles occurs only parallel to the substrate surface (there is no normal component), and it prevents its penetration into a liquid on the surface.…”