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

Abstract

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 30 to 300 kHz, its electromagnetic wavelength is 1 to 10 km, 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. Magnetostrictive TbDyFe2 (Terfenol-D) and piezoelectric lead zirconate titanate thin films are bonded together to form the 38 × 12 × 5.8 mm3 ME receiving antenna. Four 10 × 10 × 10 mm3 Rb magnets are implemented to provide an optimal DC bias for the antenna. A maximum operation distance of 2.5 m 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 of the ME receiving antenna are also characterized. The miniaturized LF ME antenna could have potential applications in portable electronics, Internet of things, and underwater communications.