Design of a 3.9-6.1 GHz Voltage-Controlled Oscillator Based on GaAs Technology

This work addresses the challenge of simultaneously achieving wideband and high linearity in voltage-controlled oscillator (VCO) by presenting a VCO architecture based on a switched-inductor structure. By toggling the switched inductor, the coupling characteristics and inductance value are altered, enabling the VCO to operate across two continuous frequency bands and thereby extending its frequency range. The frequency tuning of the VCO is achieved through a combination of a switched capacitor array and varactors, ensuring precise frequency adjustment across different operating modes. This work implements the VCO using a 0.25 μm GaAs process. Post-layout simulation results demonstrate that the presented VCO circuit consumes 40 mW of power, operates at a frequency range of 3.9–6.1 GHz, achieves a relative bandwidth of 44%, delivers an output power greater than -3 dBm, and exhibits a phase noise better than -112.3 dBc/Hz at a 1 MHz offset from the oscillation frequency. The post-layout simulation results validate the accuracy of the presented design. This work demonstrates that the proposed VCO is well-suited for applications in high-frequency wideband circuit systems.