A low phase noise wideband VCO with 8-shaped inductor

This paper presents a wideband voltage-controlled oscillator (VCO) with 8-shaped inductor for multi-band wireless communication system. The 8-shaped coils serve to reduce inductive crosstalk. The whole circuit is fully designed and simulated using 180nm CMOS technology process. The VCO provides the tuning range (TR) of 37.2% from 3.61 GHz to 5.26 GHz. The single-side phase noise at 1MHz offset are −129.5 dBc/Hz and −123.7 dBc/Hz at minimum and maximum frequencies, respectively. By adopting a 7-bit switched body-grounded NMOS varactor array with one reverse-biased diode varactor pair, the low VCO gain (less than 43 MHz/V) is achieved in whole tuning range. The layout occupies 0.32×0.46 mm2 and consumes 15 mA from the 1.8 V supply.