Varactor tunned high-Q aictive inductor with broadband tuning range

This paper presents a novel high-Q inductor using conventional grounded active inductor and feedback parallel resonance circuit. The proposed high-Q inductor using tunable LC resonance circuit (HITR) consists of the conventional active grounded inductor and feedback parallel resonance circuit which is composed of low-Q spiral inductor and MOS varactor. The novelty of the proposed structure is based on the increase of Q-factor by feeding parallel resonance circuit into gyrator structure. The high-Q inductor is fabricated by 0.18um Hynix CMOS technology. The fabricated inductor shows inductance of above 45 nH and Q-factor of over 640 around 5.4 GHz.