Inductance-Tuned LC-VCO for Reconfigurable RF Circuit Design

Abstract

This paper presents a wide tuning range LC-VCO using an on-chip variable inductor to extend tuning range. The VCO was fabricated using 0.35 µm CMOS process. The tuning range was found to be 37.8% without degradation of phase noise by inductance tuning. Wide tunable VCO with an on-chip variable inductor is one of the key circuits of reconfigurable RF circuit.

Improvement of Variable Ratio of On-Chip Variable Inductors Using Side Shield

“…Figures 1(a)-1(c) show a schematic and cross sections of the conventional variable inductor. [3][4][5][6] The variable inductor consists of an on-chip planar inductor and a metal plate above the inductor. The metal plate reduces the magnetic flux induced by the on-chip planar inductor.…”

“…[1][2][3][4][5] The variable inductor is a key passive component for realizing multi band RF circuits. 6) In this work, we propose a novel and simple structure for an onchip variable inductor to expand the variable ratio of inductance, and we achieve a variable ratio 13% larger than those of conventional variable inductors.…”

A wide-range variable-frequency resonant tunneling diode oscillator using a variable resonator suitable for simple MEMS process

“…Another approach in fabricating variable-frequency oscillators is to use a MEMS (micro-electro-mechanical system)based resonator. Variable capacitors 20) and variable inductors 21) based on a MEMS movable electrode have been investigated for variable-frequency LC-tank resonators. For millimeter-and submillimeter-wave frequency applications, transmission-line-based resonators are preferable owing to their high Q-factors.…”