Microwave phase detection with a magnetic tunnel junction

摘要

A magnetic tunnel junction (MTJ) can detect microwave magnetic field due to the interplay between the ferromagnetic resonance and tunneling magnetoresistance. Based on the fact that the tunneling resistance change is quadratically proportional to the if magnetic field, we have designed a mixing circuit in which two microwaves interfere, giving rising to a dc voltage containing the phase difference between the two microwaves. With ability to detect microwave intensity and phase, the MTJ-based device may be used for on-chip microwave network analyzer and spectrum analyzer.