A novel tuning technique for RF phase arrays using fully-integrated monolithic AC-coupled 1-D VCO network

An integrated circuit design and analysis of a fully monolithic 1-Dimensional (1-D) AC-coupled voltage-controlled-oscillators (VCOs) network for potential applications on phase array antennas is presented. This fully monolithic RF VCO array integrates inductors with on-chip bias current sources and contains an odd number of VCOs AC-coupled through switchable resistor arrays. Our design can control the phasing of this on-chip VCO-array by means of tuning the edge elements and/or by varying the coupling strength via different resistor values. SPICE simulation shows promising results allowing phase and amplitude configurations across the array offering high directivity and a possible element-to-element phase tuning arrangement that can be achieved by simply manipulating the on-chip coupling network with edge VCOs tuning. Moreover, simulation data shows that these conditions allow a ~plusmn20deg coverage from broadside without the need for phase shifters or additional circuitry complexity. This AC-coupled 1-D VCO array, therefore, shows great potential for RF active antennas applications to perform wide angle beam steering for the highly used S-band.