A Ka and V band Voltage-Controlled Oscillator for Terahertz Application in GaAs with Start-Up Relaxation

A voltage-controlled oscillator (VCO) in GaAs pHEMT with a transformer-based tank connecting at gate of transistors is present in this work. This gatetank topology realizes a easily-achievable start-up condition and a wider range of variable capacitance. Push-push structure ensures the signal of second harmonic and further simplify the topology of transmitter in terahertz (THz) band. The simulation results of proposed topology show a tuning range of 6.8%. The center frequency of two bands are 31.95GHz and 63.9GHz respectively. Their minimum output power are 0.73dBm and 16.01dBm with rejection ratio of fundamental frequency surpassing 24.27dB at second harmonic band. Stable phase noise characteristics are shown and their minimums are -104.7dBc/Hz and -98.6dBc/Hz respectively.