PROJECT TITLE :

Optimized Design of Frequency Dividers Based on Varactor-Inductor Cells

ABSTRACT:

This paper presents an in-depth analysis of a recently proposed frequency divider by 2, which is based on a parallel association of varactor-inductor cells, in a differential operation at the subharmonic frequency. The analytical study of one-cell divider enables the derivation of a real equation governing the circuit at the frequency-division threshold. This equation is employed for a detailed investigation of the impact of the circuit parts on the input-amplitude threshold and also the frequency bandwidth. Insight provided by the analytical formulation enables the derivation of a radical synthesis methodology for multiple-cell dividers, usable in harmonic balance with an auxiliary generator at the divided frequency. 2 different applications of this topology are demonstrated: a twin-part divider and a twin-band frequency divider. The former is obtained by using Marchand balun to deliver one hundred eighty$^circ$ phase-shifted signals to the 2 dividers. On the other hand, the dual-band divider is based on a completely unique configuration which combines cells with parallel varactors and cells with series varactors. Departing from the optimization procedure of the one-band divider, a easy synthesis technique is presented to center the two division bands at the required values. The techniques are applied to 3 prototypes at 2.15 GHz, 1.eighty five GHz, and one.seventy five GHz/3.ninety five GHz, respectively.