Development of sub-100 µW microwave RTD VCOs

An extremely low dc power RTD VCO IC is demonstrated by utilizing a single-mode topology. The single-mode RTD VCO is implemented using a scaled down RTD with an emitter size of 0.7 × 0.7 μm
²
. The fabricated single-mode RTD VCO shows the extremely low dc power consumption of 59 μW in the core part at 12.2 GHz. To the authors' best knowledge, the obtained core dc power consumption is the lowest reported up to date in the Ku band. In addition, the second harmonic balanced RTD VCO is also fabricated in the same MMIC technology to reduce the total dc power consumption based on a push-push principle. The fabricated second harmonic RTD VCO shows the total dc power consumption of sub-100 μW in the Ka band.