  As the Internet of Things (IoT) becomes more integral to how we live our
lives and society becomes ever increasingly connected, the need for efficient
nanoscale radio frequency detection is becoming more of a pressing issue. The
commonly used technique of a superheterodyne conversion of the incoming signal
to an intermediate frequency (IF), requires a relatively large electronic
circuit, including a local oscillator, mixer, various filters and a rectifier
(i.e. diode). In order to radically simplify this process, we propose a
spintronics-based nanometric single device whose resistance varies linearly as
a function of the incoming frequency. This analogue frequency sensor allows a
direct measurement of the incoming frequency and can work over many frequency
bands and could replace a significantly larger conventional electronics
circuit, thus reducing the footprint and potentially the energy cost. Three
types of operation of the frequency sensor are demonstrated: a HF/VHF sensor
based on a subharmonic modulation working across 9 different bands with 1-10
MHz bandwidth and 200 kHz resolution, a VHF/UHF sensor based on direct
gyrotropic excitation operating between 150-225MHz with 250 kHz resolution and
a UHF/SHF sensor based on indirect spin wave excitation operating between
2-4GHz with a 2.5 MHz resolution.
