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.