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Register a new userTransceiving signals by mechanical resonance: A low frequency (LF) magnetoelectric mechanical antenna pair with integrated DC magnetic bias
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Low frequency communication systems offer significant potential in portable electronics and internet of things (IoT) applications due to the low propagation loss and long transmission range. However, because the dimension of electrical antenna is comparable to one quarter wavelength of the electromagnetic wave that it transmits and receives, currently a gap exists between LF communication systems and IoT, as IoT generally implement miniaturized electrical antennas with a small wavelength at a high frequency while traditional LF electrical antennas are too bulky. In this paper, we present an LF magnetoelectric mechanical transmitting and receiving antenna pair to significantly miniaturize the dimension of LF antennas. As the operation principle of the magnetoelectric mechanical antenna pair is based on mechanical resonance, its dimension is reduced by four orders of magnitude compared with an electrical antenna counterpart. The transmitting and receiving antennas are the same in structure and dimensions: they are both composed of magnetostrictive Terfenol-D and piezoelectric PZT laminate, and their dimensions are both 38x12x8.2mm3. Both the transmitting and receiving antennas are integrated with DC magnetic bias to improve its performance. Antenna pair performance measurement demonstrates that a maximum operation distance of 9m is demonstrated with DC magnetic bias, while maximum operation distance without DC magnetic bias is 4m, which is reduced by 56%. The LF magnetoelectric mechanical antenna pair may be a promising candidate for the portable electronics and IoT applications.
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Due to the applications in meteorological broadcasts, radio navigation and underwater communications, low-frequency(LF) receiving antennas have been actively studied. However, because the frequency range of LF antenna is 30kHz to 300kHz, its electromagnetic wavelength is 1km to 10km, which makes LF electromagnetic antennas difficult to be implemented in miniaturized or portable devices. This article presents a miniaturized LF magnetoelectric(ME) receiving antenna with an integrated DC magnetic bias. The antenna is based on the magnetoelectric effect and operates by resonance at its mechanical resonant frequency. Thus, compared with traditional LF wire antennas, the dimension of ME antenna is reduced significantly. Compared with prior art of ME antennas which do not have DC magnetic bias, higher performance can be achieved by integrating the miniaturized DC magnetic bias. Compared with prior art of an ME antenna with bulky external DC magnetic bias, the ME antenna with an integrated DC magnetic bias significantly reduce its dimension. Magnetostrictive TbDyFe2(Terfenol-D) and piezoelectric lead zirconate titanate(PZT) thin films are bonded together to form the 38x12x5.8mm3 ME receiving antenna. Four 10x10x10mm3 Rb magnets are implemented to provide an optimal DC bias for the antenna. A maximum operation distance of 2.5m is demonstrated with the DC magnetic field bias, 2.27 times of the maximum operation distance of the antenna without DC magnet field bias. The efficiency, gain and quality factor the ME receiving antenna is also characterized. The miniaturized LF ME antenna could have potential applications in portable electronics, internet of things and underwater communications.
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