Digital and analogue modulation and demodulation scheme using vortex-based spin torque nano-oscillators

Alex S Jenkins,Lara San Emeterio Alvarez,Paulo P Freitas,Ricardo Ferreira

doi:10.1038/s41598-020-68001-6

Alex S Jenkins, Lara San Emeterio Alvarez + Show 2 more

Open Access

https://doi.org/10.1038/s41598-020-68001-6

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Abstract

In conventional communications systems, information is transmitted by modulating the frequency, amplitude or phase of the carrier signal, which often occurs in a binary fashion over a very narrow bandwidth. Recently, ultra-wideband signal transmission has gained interest for local communications in technologies such as autonomous local sensor networks and on-chip communications, which presents a challenge for conventional electronics. Spin-torque nano-oscillators (STNOs) have been studied as a potentially low power highly tunable frequency source, and in this report we expand on this to show how a specific dynamic phase present in vortex-based STNOs makes them also well suited as Wideband Analogue Dynamic Sensors (WADS). This multi-functionality of the STNOs is the basis of a new modulation and demodulation scheme, where nominally identical devices can be used to transmit information in both a digital or analogue manner, with the potential to allow the highly efficient transmittance of data.

Highlights

In conventional communications systems, information is transmitted by modulating the frequency, amplitude or phase of the carrier signal, which often occurs in a binary fashion over a very narrow bandwidth
An Spin-torque nano-oscillators (STNOs) usually consists of a magnetic tunnel junction (MTJ), with free and fixed magnetic layers separated by an insulating layer, and where the free layer oscillates at high frequencies due to either a dc current, via the spin-transfer torque e ffect[42,43], or a resonant radio-frequency c urrent[30] or magnetic field[44,45,46]
When a radio-frequency signal arrives to the integrated field line antenna, it will result in a dynamic response from the free layer of the MTJ, the nature of which depends on the frequency and power of the incoming signal

Summary

Introduction

Information is transmitted by modulating the frequency, amplitude or phase of the carrier signal, which often occurs in a binary fashion over a very narrow bandwidth.

Results

Conclusion