Spintronic RF-Direct on-off Keying Modulation Using a Frequency Division Multiplex

Abstract

This paper presents the results of spintronic wireless communication using a new modulation method, spin RF-direct on-off keying modulation using a frequency division multiplex (FDM), which modulates amplitude and frequency simultaneously with a spin torque nano-oscillator (STNO) array. For the new modulation technique, each channel can be assigned to every STNO on the STNO array, and each STNO is simultaneously modulated by on-off keying with digital data directly. These modulation technologies have the advantage of increasing the data transmission rate by the number of operating STNOs. In recent years, efforts to increase the speed of transmission are important as the amount of data it sends increase. The receiver demodulates data on every channel through a band pass filter acquiring the frequency assigned to each channel, respectively. To initially confirm the possibility of realizing spin RF-direct on-off keying modulation using an FDM, we demonstrated the proposed modulation technique with two STNOs in an array, setting one STNO at 3.5 GHz frequency and the other at 4.2 GHz, and communicated wirelessly with a two-channel receiver in the near field. A data rate of up to 4 Mbps is obtained with the new modulation technique under 10 mm distance, and the DC power consumption is 0.18 mW per STNO in transmitter, including logic circuit operation.