A Voltage-Controlled Oscillator with Dual-Band Structure in 0.18-µm CMOS Technology

A voltage-controlled oscillator (VCO) with dual-band structure in 0.18-µm CMOS technology is proposed in this paper. By adopting a fourth-order LC-type resonant mechanism, the proposed CMOS VCO could generate frequency band 1 and band 2 for wireless dual-band direct-conversion receiver (DCR) applications. The proposed VCO uses only one control voltage to achieve dual-band function and to reduce frequency control procedure. The measured output frequencies are 1.14 GHz for the frequency band 1 at control voltage of 0 V and 3 GHz for the frequency band 2 at control voltage of 1.7 V, respectively. For the frequency band 1 at 1.14 GHz and frequency band 2 at 3 GHz, the measured phase noise of -100.3 dBc/Hz and -107.42 dBc/Hz at 1-MHz frequency offsets, respectively. The proposed dual-band CMOS VCO core consumes 10.5 mW at 1.7 V supply.