Extremely-Low-Frequency Transmitter Based on Oscillating Electret Toward Increasing Data Rate With Low Power Consumption

The mechanical antenna (MA) is a potential solution for the extremely-low-frequency (ELF, 3–30 Hz) transmitter enabling industrial informatization. It can have the advantages of miniaturization and high efficiency compared to conventional transmitters. However, the current ELF MA has an issue with both high inertia and a long delay in symbol switching. Not only does this lower the data rate, but it also causes unnecessary power consumption in operation. This article proposes a compact ELF transmitter based on a heterogeneous architecture of piezoelectric cantilevers and oscillating electret, as well as a relevant information transfer program. The actuator fabricated from composite piezoelectric material exhibits a rapid dynamic reaction. Merging this with efficient spectrum utilization increases the data rate and reduces power consumption. A proof of concept demonstration conducted at a frequency of 26.4 Hz attained a data rate of 21 bit/s while consuming a mere 1.52 W of power. In addition, increasing the charge density of the electret can expand the transmission distance without requiring extra power consumption, thus adapting to more challenging applications such as Underwater Internet of Things, Through-the-Earth communication, pipeline inspection, and underground detection.