A miniaturized low frequency (LF) magnetoelectric receiving antenna with an integrated DC magnetic bias

Abstract

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 38ⅹ12ⅹ8.2mm 3 . 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.Radio-frequency communication has been a critical component for human society since its invention in the late nineteenth century 1, 2 . A variety of radio-frequency communication systems, such as medium frequency(MF) for AM radio communications, ultra-high frequency(UHF) communication systems for television broadcasting and cellphone communications [3][4][5][6][7] , and mmWave for 5G communications and mmWave radar 8-10 have been widely implemented based on scientific and technological advancements, which greatly improve our daily life. As the interface between radio waves propagating through space and electric currents moving in metal conductors, antennas have emerged since the beginning of 20 th century as one of the most critical components in radio-frequency communications. The earliest antennas were wire type, primarily as single elements 11 . In the past 40 years, advanced antennas including microstrip antennas, dielectric resonator antennas, and multiple input-multiple output (MIMO) technology are extensively studied [12][13][14] . The microstrip antennas are applied in television broadcasting 15 and 5G WLAN application 16 . The waveguide slot antennas and MIMO antennas are applied in 5G communication systems and mmWave radar [17][18][19] .Low frequency(LF) antennas, which operate at frequencies between 30-300kHz, have been widely implemented in meteorological broadcasts, radio navigation, and underwater communication 20,21 . Compa...

Magneto‐Mechano‐Electric Antenna for Portable VLF Transmission

“…It can be calculated from the B ‐field patterns that the directivity D of the ME cantilever is 3 dB. [ 5 ]…”

“…It can be calculated from the B-field patterns that the directivity D of the ME cantilever is 3 dB. [5] The radiation signature of the MME antenna is significantly different than the ME cantilever. The additional oscillating magnetic dipole created by the physical motion of magnet at the free end of the ME antenna results in extra magnetic radiation.…”

“…[12] To enable practical VLF communication, it is imperative to develop technologies that can enable VLF antenna system miniaturization and portability. [4,5] Although electrically small antennas do show some advantages due to their compact size and low cost, the relatively low radiation efficiency and low bandwidth still remain as obstacles for practical applications in VLF communication. [2,13,14] In contrast to the most widely used dipole antenna, mechanical antennas that function through the coupling of the electromagnetic field by using the mechanical movement of charge or magnetic dipole have gained prominence.…”

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

“…Specifically, electrets are used as carriers of net electrostatic charges. Then, the electret is driven by a controllable mechanical device to achieve ELF transmission 17 – 20 . As a result, the total charge density characterizing the amount of net charge carried by the electret is a key factor in determining the antenna’s radiation intensity.…”

Design and Optimization of a Micron-Scale Magnetoelectric Antenna Based on Acoustic Excitation

“…Dong et al applied ME antenna to VLF (Very Low Frequency, 3–30 KHz) [ 25 ], and they conducted the near-field testing, not far-field testing. Niu et al studied a miniaturized low-frequency ME receiving antenna with integrated DC bias, which can achieve a higher performance than existing antennas without a DC bias [ 26 ], but they only studied the reception of the antenna, not the transmission of the antenna. Kevin used the Landau–Lifshitz–Gilbert (LLG) equation to accurately analyze the magnetoelastic coupling problem in the ME antenna [ 27 ], but they did not consider the spatially dependent electrodynamics governed by Maxwell’s equation.…”