METHOD AND APPARATUS WITH IMPROVED VARACTOR QUALITY FACTOR

摘要

An embodiment of the present invention provides an apparatus, comprising a varactor; and at least one eternal high-Q fixed capacitors combined with the varactor thereby improving the Q of the varactor. The at least one external high-Q fiE5d capacitor may combined in series with the varactor or in parallel with the varactor. Further, the varactor may be constructed of an internal low-tuning high-Q material with high-Q and large capacitance but low tuning range. The apparatus of one embodiment of the present invention may be incorporated into a 4-pole bandpass filter enabling Q improvement on the circuit performance or also may be incorporated into an amplifier or a voltage controlled oscillators or a phase shifters. Another embodiment of the present invention provides an apparatus, comprising a resonator and a varactor variably coupled into the resonator through an RF transformer, wherein by varying a coupling factor, the Q-factor and the tunability of the apparatus is capable of being affected.