X- and K-band tunable phase generation circuits for monolithic mm-wave phased arrays

This paper presents design and characterization of two polyphase generation circuits, operating at X and K bands. These are crucial building blocks of an intended mixed-signal scalable architecture, suitable for integration of large beamformers on silicon technologies, operating at mm-wave frequencies. Circuits are designed with a mixed-signal approach: signals and topologies are digital, but performance and accuracy are achieved with analog-IC techniques. The novel topology proposed for the phase generator bases its operation on the time delay of matched ECL inverters loaded with quasi-matched varactors. One core phase shifter generates the phase gradient step, and it is reused several times to generate eight output differential signals of different phases. Without using any inductive component, the two phase generators provide 4 bit phase resolution in the 5-17 GHz and 11-26 GHz bands requiring 534 mW and 615 mW respectively, and are excellent candidates for the silicon integration of high-density beamformers.