Abstract:
The feasibility of using standard 0.18 mu m CMOS technology for low cost wideband monolithic microwave integrated circuits (MMICs) at similar to 27GHz is demonstrated. Three monolithically integrated distributed voltage controlled oscillators (DVCOs) with a novel gain cell comprising of n-FET common source with p-FET current-source load are designed. Two of the DVCO's have 3 stages of the gain cell while the third has 4 stages. Top Layer metal is used a coplanar wave guide for producing on-chip inductive elements. An important feature of these DVCOs is the use of body bias variation for very large frequency tuning. Simulation results indicate that the 4-stage DVCO achieves a tuning range of 22.43-23.42GHz i.e 990MHz whereas the 3-stage DVCO has a tuning range of 25.82-27.10GHz i.e 1.28GHz, with respectively similar to 0.5dBm and similar to 1dBm change in output power over tuning range for DVCOs. The best value of phase noise for 3-stage DVCO is obtained by applying reverse body bias on n-FETs. For a reverse body bias voltage of -IV, the phase noise is -97.39dBc/Hz at 1MHz offset from 26.87GHz.
