Design of a multiband VCO using a cascode FET mixer

Abstract

This paper presents the voltage-controlled oscillator (VCO) with a cascade FET structure and self-oscillatory property. The self-oscillation (SO) frequency of the designed VCO is 1.45 GHz. and the frequency is tuned from 1.06 to 1.42 GHz by using an added varactor diode. Mixing SO signals with the external signal of 500 MHZ having a 0-dBm power level. the VCO can generate various LO signals from 560 to 1920 MHz. The tuning range of the VCO is expanded from 29% to 109.7%. The implemented VCO operates at 3 V with 30-mA current consumption.