Design of an ultra-low-noise 1.75-GHz VCO using InGaP/GaAs HBT technology

An integrated voltage‐controlled oscillator (VCO) operating at 1.75 GHz is designed using the InGaP/GaAs HBT process. The proposed noise‐removal circuit and FR‐4 substrate structure in this paper show an improved characteristic of phase noise and a smaller VCO dimension, respectively. The frequency‐tuning range of the VCO is about 200 MHz and the phase noise at 120‐KHz offset is −119.3 dBc/Hz. The power consumption of the VCO core is 11.2 mW at 2.8‐V supply voltage and the output power is −2 dBm. The calculated figure of merit (FOM) is 191.7, which shows the best performance, as compared with the previous FET or HBT VCOs. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 41: 196–198, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20090