Experimental results of active and passive isolation techniques for multiple K-band LC-oscillators on silicon ICs

Measurement results of techniques for isolating multiple K-band oscillators on silicon are reported. Implemented in a 130 nm CMOS process, the experimental results of two 21 GHz oscillators show the validity of the adopted techniques. A measured worst-case spectrum leakage level of -77 dBm is reported between two identical VCOs when independently injection-locked to ninth sub-harmonic tones. De-embedding efforts showed that the lateral coupling between the RF probes dominated the enclosed results during measurements and further suggest that the achieved isolation levels are better than those reported. The reported phase noise of -107.17 dBc/Hz at 1MHz offset, the absence of inter-injection locking phenomena and the ability to steer the phases of each oscillator independently attest to the successful isolation levels achieved. It is believed that these results are the best reported isolation levels for oscillator circuits operating at K-Band on silicon and are reported herein due to the foreseen need to realize multiple independently running RF/millimeter-wave VCO´s on a single chip in future IC´s.