In this paper, we propose a technique to extend the tuning range (TR) of Colpitts voltagecontrolled oscillators (VCOs). To achieve a wide tuning range, we use variable capacitive feedback technology to extend the tuning range while achieving lower phase noise than that of the conventional Colpitts VCOs. In addition, the structure benefits from the dynamic forwardbody selfbiased technique to reduce the power consumption and facilitate the startup condition. Based on a 90 nm CMOS technology, a VCO is designed. The VCO achieves a phase noise of -101.9 dBc/Hz at 1 MHz offset, the TR of 28.1%, and the quality factor of -192.2 dBc/Hz considering the tuning range. The chip consumes 5.8 mW of power at 1 V voltage and occupies a 0.45 mm2 of area.