Ultra-Low-Power Series-Feedback Frequency Divider Using 0.15- $\mu{\rm m}$ GaAs pHEMT\´s at W-Band

A frequency divider with a very low dc power consumption of 3 mW is demonstrated using 0.15 μm GaAs pHEMT technology at W-band. The frequency divider is based on an injection lock topology using a cascode field effect transistor (FET) structure. For low-power operation, the oscillator is configured in series-feedback topology using the upper FET as a gain cell and the lower FET as a capacitive feedback element. An impedance-transforming transmission line is inserted between the two FET´s to further reduce the dc power consumption. Besides, the locking range is enhanced by adding varactor tuning at the gate of the upper FET. When the input power of 0 dBm is applied, the frequency divider operates at 77 GHz with an output power of -20 dBm in a bandwidth of 4.2 GHz (5.5%) while consuming only 3 mW from 1V power supply. Overall bandwidth with varactor tuning is from 68.4 to 82.0 GHz (13.6 GHz, 18.1%). To our knowledge, the measured power consumption of the presented frequency divider is among the lowest from the reported W-band frequency dividers.