The present disclosure provides a tunable signal source having a plurality of oscillator cores having a coupling input, a coupling output, and a power output that is common to each of the plurality of oscillator cores. Also included is a plurality of tunable phase shifters wherein corresponding ones of the plurality of tunable phase shifters are communicatively coupled between the coupling input and the coupling output of corresponding ones of the plurality of oscillator cores, thereby forming a loop of alternating ones of the plurality of oscillator cores and alternating ones of the plurality of tunable phase shifters.