A K-band Diffential-output GaAs pHEMT Voltage Controlled Oscillator

In this paper, a K-band GaAs pHEMT voltage-controlled oscillator chip with differential-output is presented. The differential Colpitts Structure is adopted in this circuit design with two core oscillating loops integrated inside. Simulated results show this oscillator design can operates from 22.99GHz to 27.39GHz, with its relatively tuning frequency bandwidth of 17.47%. The single-ended output power of the chip is around 5dBm. A prototype chip is fabricated using PD25 process of Win foundry and is soldered on the test printed circuit board for performance measurement. The measurement results agree well with the simulated results. The prototype chip can operate from 23.24GHz to 28.17GHz, with its tuning voltage varied from -3V to 0V, achieving a relatively tuning bandwidth of 19.18%. The measured output power of the prototype is 4.5dBm with the differential-output single-ended. Phase noise performance is also provided, with the simulated and measured results agreed with each other well. Phase noise at 100KHz offset for the operating frequency band is around -80dBc/Hz.