28 GHz Quadrature Frequency Generation Exploiting Injection-Locked Harmonic Extractors for 5G Communications

This paper proposes a mm-wave quadrature frequency generator using injection-locked harmonic extractors (HEs) incorporated with quadrature class-F oscillators. While maintaining high output levels at 28 GHz, the utilization of injection locking technique improves the effective quality ( Q)-factor and helps to achieve a fundamental harmonic suppression of 60 dB. This results in an FoM of the entire frequency generation system reaching -184 dB. The consideration of quadrature phase mismatch induced by electromagnetic coupling between quadrature buffers is also discussed.