A miniaturized mechanical antenna based on FEP/THV unipolar electrets for extremely low frequency transmission

Abstract

An electret-based mechanical antenna (EBMA), which can transmit extremely low frequency (ELF) electromagnetic signals, has the advantages of miniaturization and high transmitting efficiency, with great potential applications in air, underwater, and underground communications. To improve the charge density of the electret, which is a key factor in determining the radiation performance of an EBMA, this work proposes a fluorinated ethylene propylene/terpolymer of tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride (FEP/THV) unipolar electret exhibiting negative polarity, reaching a total charge density up to −0.46 mC/m2 for each layer of electret. Long transmission distances can be achieved in sea water, soil, and air using a 3-layer-FEP/THV-based EBMA with a compact volume of 5 × 10−4 m3. As an application demonstration, binary ASCII-coded ELF information of “BUAA” is successfully transmitted with a power consumption < 5 W.

An ultra-compact mechanical antenna based on PTFE highly charged electret for extremely low frequency communications

“…At the cost of such a large power consumption, the increase in communication capability is less than 1000 times, which is clearly inefficient for a transmitting antenna. For the electret type mechanical antenna, this paper is compared with the literature [ 16 ], and the radiation capacity of this paper is increased by a factor of 10 for the same size. Besides the time-varying magnetic field of the rotating electret mechanical antenna decreases by the quadratic of the communication distance.…”

“…The rotating electret type MA generates a time-varying electric field by rotating the electret, which results in an oscillating static electric field and the production of electromagnetic waves [ 15 ]. However, when compared to permanent magnet mechanical antennas that can reach a range of 100 m, electret mechanical antennas can only communicate at a range of 10 m. This limitation stems from the relatively weak charge storage capability of natural electret materials (the best electret materials have a charge density of 0.46 mC/m 2 [ 16 ]) and piezoelectric to store charge.…”

A High‐Q Electric‐Mechano‐Magnetic Coupled Resonator for ELF/SLF Cross‐Medium Magnetic Communication

“…Recently, mechanical antennas (MAs) have been proposed as a potential solution to improve the low-frequency emitting efficiency and tackle miniaturization concerns. [5] MAs are implemented into low-frequency communication systems through multiple approaches, including the permanent magnet rotation type, [6][7][8][9][10][11] piezoelectric/electret type, [12][13][14][15] and piezoelectric driving poled ferromagnetic type. [16][17][18][19][20][21][22][23] The MA based on rotating permanent magnet has a high power consumption due to its nondirect driving method; the piezoelectric/electret type manifests a weak radiation capability, and it is unsuitable for ELF/SLF magnetic field transmitting.…”

Stretchable π-conjugated polymer electrets for mechanoelectric generators

“…Second, MEGs do not require an electrolyte and possess high impedance and thus are thought to be safe for human-adaptive power supplies. In recent years, with improvements in the performance of MEGs [2,3] along with the miniaturization and power savings of electronic devices, various practical applications for MEGs, such as wearable devices [4][5][6], sensors [7,8], and transmitters [9], have emerged.…”