Design and implementation of a 6-GHz array of four differential VCOs coupled through a resistive network
This paper presents the design and the implementation of a fully monolithic coupled-oscillator array, operating at 6 GHz with close to zero coupling phase, in 0.25 mu m BICMOS silicon germanium process. This array is made of four LC-NMOS differential VCOs coupled through a resistor. The single LC-NMOS VCO structure is designed and optimized in terms of phase noise with a graphical optimization approach while satisfying design constraints. At 2.5 V power supply voltage, and a power dissipation of only 125 mW, the coupled oscillators array features a simulated phase noise of -127.3 dBc/Hz at 1 MHz frequency offset from a 6 GHz carrier, giving a simulated phase progression that was continuously variable over the range -64A degrees A < Delta I center dot < 64A degrees and -116A degrees A < Delta I center dot < 116A degrees. This constant phase progression can be established by slightly detuning the peripheral array elements, while maintaining mutual synchronization.
bicmos lc-nmos vco phase noise coupled oscillator beam scanning