A 5.6∼8.2GHz QVCO with a new DCCA circuit

The paper presents a high frequency wideband quadrature voltage-controlled oscillator (QVCO). In the QVCO, a new digital controlled capacity array (DCCA) circuit is proposed to break the trade-off between high frequency and wideband. With this new DCCA circuit, the QVCO achieves higher frequency and wider band. Parallel coupling transistors are attached to generate precise quadrature signal. A phase-shift network is introduced to eliminate Bi-mode oscillation phenomenon. The QVCO is designed with 0.13μm CMOS technology. Post simulation results show that the QVCO achieves a 5.6~8.2GHz continuous tuning range with a phase noise 106.5dBC/Hz at 1MHz offset when frequency is 8.2GHz.