Expanding the Tuning Range of a Varactor-Tuned Circuit

摘要

A theoretical model of a varactor-tuned circuit is studied. The capacitance-voltage characteristic of the varactor is approximated in the conventional manner. It is demonstrated that constraints imposed on the tun- ing slope have a strong effect on the tuning range. Analytic expressions connecting the slope ratio with the tun- ing range and the varactor capacitance ratio are derived. A technique to optimize the varactor parameters is sug- gested.