Compact InP-based HBT VCOs with a wide tuning range at W- and D-band

Compact monolithic integrated differential voltage-controlled oscillators ( VCOs) operating in W-band were realized using InP-based heterojunction bipo lar transistors (HBTs), The oscillators, with a total chip size of 0.6 by 0 .35 mm(2), are based on a balanced Colpitts-type topology with a coplanar t ransmission-line resonator, By varying the voltage across the base-collecto r junction of the HBT in the current mirror and by changing the current in the VCO, the oscillation frequency can be tuned between 84 and 106 GHz, At 100 GHz, a differential voltage swing of 400 mV is obtained, which should b e sufficient to drive 100-Gb/s digital logic. By combining the balanced out puts of a similar differential VCO in a push-push configuration, a compact source with close to -10 dBm output power and a tuning range between 138 an d 150 GHz is obtained.