On-chip high-Q (>3000) transformer-type spiral inductors

High quality factor (>3000) transformer-type spiral inductors are realised in a 0.18 /spl mu/m complementary metal-oxide-semiconductor with active magnetic energy feedback from the secondary coil to the primary coil. This approach is robust and compatible with the mainstream integrated circuit technologies and has potential to achieve high-Q reactance with low power, low noise and high linearity. The fabricated inductors exhibit Q /spl sim/ 3000 between 1.5 to 2.1 GHz.