Metamaterial mechanical antenna for very low frequency wireless communication

Very low frequency wireless communication (3-30 kHz) often is restricted by the antenna size and complex impedance matching network in practical applications. Mechanical antenna has recently stimulated much practical research interest due to the potential capacity for breaking the size limitation. However, mechanical antenna is barely investigated from the perspective of material science. Here, we demonstrate a compact piezoelectric metamaterial mechanical antenna with high radiation efficiency, multi-frequency bands, and small size. Three operating frequencies at 22 kHz, 24 kHz, and 26 kHz are independently adjusted by the structure parameters and material of a piezoelectric radiating unit cell, and the modulation range is beyond 15 kHz. The basic parameters studies reveal the detailed modulation mechanism and provide a theory base for the metamaterial antenna design. Except for the smaller than 1/1000 wavelength size, the radiated magnetic field intensity is also averagely increased by 3 x 10(4) fT. All the simulated results demonstrate the great potential of the proposed piezoelectric metamaterial antenna in the applications of portable, small, high-performance wireless communication devices.