A W-band Push-Push VCO with G_m-Boosted Colpitts Topology in 90-nm CMOS Technology

This paper presents a W-band push-push VCO design and implementation in 90-nm CMOS technology, which is expected to be used for a 94-GHz RF transceiver. The proposed VCO adopts a differential Colpitts topology with the drain to source (DS) feedback operating at fundamental frequency. This VCO is biased by a current-switching transistor pair with dynamic forward-body biasing technique. Thus, the negative conductance of VCO can be enhanced for reliable start-up. A greater W-band signal can be obtained by a gm-boosted doubler. In addition, the current-reuse technique realizes low power design. The center frequency of proposed VCO is 90.1 GHz with the tuning range of 2.24 %. This VCO provides the highest frequency of 91.11 GHz and the corresponding output power of-0.2 dBm. The VCO consumes 25.43 mW from a 1.8-V supply and exhibits the phase noise of-109.22 dBc/Hz and FOM of-174.3 at 10 MHz offset.