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
$\mu{\rm m}$
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
$-20 ~{\rm dBm}$
in a bandwidth of 4.2 GHz (5.5%) while consuming only 3 mW from 1 V 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.