Optimized phase noise of LC VCO using an asymmetric‐inductance tank in InGaP/GaAs HBT technology

This paper describes fully integrated low-phase-noise MMIC voltage-controlled oscillators (VCOs) for an adaptive-feedback interference-cancellation system (AF-ICS). The asymmetric- and symmetric-inductance tank structures were combined with VCOs to obtain VCOs with low-phase-noise performance. The asymmetric-inductance tank VCO (AIT-VCO) has a tuning range of 261 MHz with an output power of −11.53 dBm at 1.715 GHz. Furthermore, the phase noise of this VCO is −117.3 dBc/Hz and −129.3 dBc/Hz at 100-kHz and 1-MHz offset frequencies, respectively. The symmetric-inductance tank VCO (SIT-VCO) has a tuning range of 160 MHz with an output power of −15 dBm at 1.664 GHz. Furthermore, the phase noise of this VCO is −102.4 dBc/Hz and −121.9 dBc/Hz at 100-kHz and 1-MHz offset frequencies, respectively. Each of these VCOs occupies a total chip area of 0.9 × 0.9 mm2. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1035–1040, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21593