A　wide　tuning　range,　low　K-VCO　and　low　phase　noise　VCO　is　presented　in　this　paper　by　combining　fully　differential　active　inductor　(DAI),　switched　capacitor　array　and　MOS-based　variable　capacitors.　The　adoption　of　the　DAI　instead　of　spiral　inductor　in　the　LC　tank　reduces　the　phase　noise　of　VCO　due　to　high　Q　value　of　DAI.　The　multiple　tuning　modes　by　tunable　active　inductor,　switched　capacitor　array　and　variable　capacitor　make　VCO　have　a　wide　tuning　range　of　oscillation　frequency　and　lower　K-VCO.　Based　on　TSMC　0.18　mu　m　CMOS　process,　the　VCO　is　verified　by　Advanced　Design　System　(ADS).　The　results　show　that　the　oscillation　frequency　can　be　tuned　from　988MHz　to　4601MHz　with　a　wide　tuning　bandwidth　of　129.3%,　and　the　lowest　phase　noise　is　-116.88dBc/Hz　at　1MHz　offset,　and　the　K-VCO　is　as　low　as　45-550MHz/V.