A dual-tapped microstrip resonator VCO

A high loaded Q resonator and harmonic output topology are both potent technique to realize a low phase noise oscillator. This paper proposes a low phase noise Voltage Controlled Oscillator (VCO) with harmonic output, using a dual-tapped microstrip resonator of the high loaded Q factor. The paper also shows a load circuit configuration to suppress the output of the fundamental oscillation. The output frequency and the phase noise of the prototyped VCO are 15.652 GHz to 15.7 GHz, and less than -104dBc/Hz at 100kHz offset from the carrier, respectively. The fundamental and the second harmonic output are less than -37.6dBm, and -8dBm, respectively. The VCO fabricated on a resin substrate achieves the low phase noise on a par with other reported dielectric resonator oscillators (DROs), while manufacturable at lower cost than DROs.