A beam-scanning architecture using A 6-GHz array of four coupled differential VCOs for automotive communications

This paper presents the design and the implementation of a fully monolithic coupled-Voltage Controlled Oscillators (VCOs) array, operating at 6 GHz, in 0.25 μm BICMOS SiGe process. This array is made of four LC-NMOS differential VCOs coupled through a resistive network and can be used to perform beam-scanning by controlling the relative phases of the signals applied on each element of a linear antenna array. At 2.5 V power supply voltage, and a power dissipation of only 125 mW, the coupled VCO 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 is continuously variable over the range -64° <; Δφ <;64° and -116° <; Δφ <; 116°. This constant phase progression is established by slightly detuning the peripheral array elements, while maintaining mutual synchronization.