CMOS digital controlled oscillator with embedded DiCAD resonator for 58–64GHz linear frequency tuning and low phase noise

A digital controlled artificial dielectric (DiCAD) differential transmission line is embedded in 90 nm CMOS to digitally tune a 58-64 GHz DCO. DiCAD varies epsiv_r,eff from 18.8 to 32.5. A shunt open stub DiCAD provides discrete capacitive tuning with 13.1deg S11 phase variation. The core oscillator is an inductively loaded differential, cross-coupled NMOS pair. Large nonlinear varactors are avoided, and the phase noise is better than -90 dBc/Hz at 1 MHz offset. Linear tuning bandwidth of 9.3% with a 61 GHz center frequency occupying 0.01 mm² is achieved. Power consumption is 8.52 mW with 1.2 V.