Compact RF Impedance-Spectrum-Analyzer For Lateral Field Excited Liquid Acoustic Wave Sensors

A compact RF impedance-spectrum-analyzer (RF-ISA) has been developed and applied to a Lateral Field Excited (LFE) liquid acoustic wave sensor, which is sensitive to both, the mechanical and the electrical liquid property changes. The developed RF-ISA was used to determine the impedance spectrum of a LFE sensor exposed to various liquids with varying electrical and mechanical properties and to calculate the series resonance frequency and resistance at the sensor's conductance maximum. The combination of the LFE sensor and the RF-ISA electronics results in a compact and portable liquid sensing unit, which not only has many sensing applications but also can provide insight into the piezoelectric excitation and transduction mechanisms.