| In the present study, Several 4.5 MHz LFE devices with different electrode configurations, including the dual-gap electrode, single-turn Archimedes spiral electrode, two-turn Archimedes spiral electrode and two-turn symmetric spiral electrode, were fabricated and tested. A common LFE device with the single-gap electrode is also fabricated for comparing their performances. A major resonance peak was observed in all devices in air. However, devices with the single-gap electrode and the two-turn symmetric spiral electrode offer higher Q value than other devices. The device with the dual-gap electrode shows the maximum frequency change compared to other devices when the sensing surface of these devices is exposed to water and 0.06 wt% NaCl water solution. Theoretical analysis for these phenomena is given. |