SBIR-STTR Award

Magnetostrictive electroactive (ME) composite element as magnetic receiving antenna for near-field magnetic communication is proposed. ME element is comprsed of lamination of a magnetostrictive material and piezoelectric material. Magnetrostrictive material exhibits magnetstriction that strains under magnetic field. In a ME element, magnetrostrictive material is mechanically coupled to piezoelectric material, thus resulting a superior mutual magnetic-electrical coupling. The ME element, similar to quartz crystal oscillator, also resonate when driven at its resonance frequency from electrical or magnetic excitations. Coupled mode theory was used to revile the fundamentals of the proposed technique. The theoretical results shows that if the transmit (inductive loop coil) and receive antennas (ME element) are tuned to the same resonance frequency, it would potentially great enhance the signal strength and increase communication distance. Further, using back-scattering of the ME element to communicate to the loop antenna is proposed for applications where the battery life is critical. through coupled resonance mode to achieve longer communication distance, faster data rate and smaller size of the equipment. In addition, the ME device is totally passive; the power consumption of the system is expected to be very low.

Keywords:
Magnetic, Communication, Wireless, Magnetostrictive, Electroactive, Me

Environmental factors can strongly attenuate electromagnetic waves, degrading communication distance, data rate, signal-to-noise ratio and reliability of RF systems. Magnetic near-fields are an attractive alternative to propagating electromagnetic wave communication because the former are not negatively impacted in environments that interfere with RF communication. Near-field magnetic communication (NFMC) has traditionally been realized through coil-to-coil inductive coupling. Because magnetic near-field strength decreases rapidly (1/r3) with increasing distance from the source, receive coils must contain many electrical turns, making communication over 100s of meters challenging. This Phase I program demonstrated a novel approach to NFMC by replacing the receive coil with a magnetostrictive/electroactive (ME) laminated receiver measuring typically 20 mm × 8 mm × 0.4 mm. The pT field at 140 m from a 46 cm diameter coil of 6 Ampere-turns was readily detected with the ME receiver. The Phase II effort will further develop the NFMC system by improving the internal properties of the ME receiver, designing sophisticated and power efficient transmit and receive electronics, and optimizing system efficiency. The Phase II prototype NFMC system will be wearable and provide soldiers with 2-way voice communication over many hundreds of meters and data transmissions (such as text) to distances over 1 km.

Keywords:
Magnetic, Communication, Wireless, Magnetostrictive, Electroactive, Me