Wideband VCO with triple tuned circuits in C-Ku band

This paper describes a wide-band voltage controlled oscillator (VCO) with the triple oscillation bandwidth and a better flatness of the phase noise in the oscillation bandwidth using triple varactor-tuned circuits. Altering capacitances of varactor diodes connected to every ports of a HBT in the same direction, the oscillation bandwidth of more than 1.5 octaves has been obtained. A fabricated VCO employing the triple-tuned circuits and a GaAs HBT has covered 1.56 octaves bandwidth achieving the phase noise of -114.9 dBc/Hz /spl plusmn/2.9 dB at 1 MHz offset from the carrier and the output power of 3.4dBm /spl plusmn/2 dB in C-Ku band.