paper

Low Power Microwave Signal Detection With a Spin-Torque Nano-Oscillator in the Active Self-Oscillating Regime

arXiv:1704.03585 · doi:10.1109/TMAG.2017.2694847

Abstract

A spin-torque nano-oscillator (STNO) driven by a ramped bias current can perform spectrum analysis quickly over a wide frequency bandwidth. The STNO spectrum analyzer operates by injection locking to external microwave signals and produces an output DC voltage $V_{dc}$ that temporally encodes the input spectrum. We found, via numerical analysis with a macrospin approximation, that an STNO is able to scan a $10 GHz$ bandwidth in less than $100 ns$ (scanning rate $R$ exceeds $100 MHz/ns$ ). In contrast to conventional quadratic microwave detectors, the output voltage of the STNO analyzer is proportional to the amplitude of the input microwave signal $I_{rf}$ with sensitivity $S = d V_{dc} / d I_{rf} \approx 750 mV/mA$ . The minimum detectable signal of the analyzer depends on the scanning rate $R$ and, at low $R \approx 1 MHz/ns$ , is about $1 pW$ .

5 pages, 5 figures