Design of a 54 to 63 GHz differential common collector SiGe Colpitts VCO

The design of a 60 GHz differential common collector Colpitts VCO in SiGe HBT technology with 180 GHz ft is presented. The impact of parasitics on the negative resistance is evaluated and an extension regarding existing design equations is derived. Within a wide tuning range from 54.1 to 62.7 GHz, a phase noise performance between -98 and -90 dBc/Hz is measured at 1 MHz offset. To the knowledge of the authors this is the best phase noise performance of a 60 GHz VCO in silicon yielding such a high tuning bandwidth. At a dc voltage of 2 V and a dc current of 14 mA, the output power amounts to -5 ± 1 dBm.