A new phase noise reduction method of oscillator by loaded Q improvement using dual feedback topology

• Published in: IEEE microwave and wireless components letters 2005-01, Vol.15 (1), p.39-41
• Main Authors: LEE, Young-Taek, LEE, Jaechun, NAM, Sangwook
• Format: Article
• Language: English
• Subjects: Applied sciences; Circuit analysis; Circuit properties; Circuit topology; Coupling circuits; Dual feedback; Electric, optical and optoelectronic circuits; Electronics; Exact sciences and technology; Feedback; loaded; Microstrip resonators; Microwave circuits, microwave integrated circuits, microwave transmission lines, submillimeter wave circuits; Noise measurement; oscillator; Oscillators; Performance evaluation; Phase measurement; Phase noise
• ISSN: 1531-1309; 1558-1764
• DOI: 10.1109/LMWC.2004.840980

This letter presents a new method to reduce the phase noise in oscillator based on the loaded Q improvement approach. A hairpin resonator is weakly coupled to the two microstrip lines to improve the loaded Q of it and the dual feedback topology is used to enable the start-up oscillation condition to be satisfied. The high loaded Q property of the resonator in the proposed oscillator circuit is analyzed using the CAD simulation. For comparison the phase noise performances of the conventional hairpin resonator oscillator and the oscillator using the dual feedback are measured. Measurements show that the oscillator using the dual feedback exhibits a low phase noise performance of -109.1 dBc/Hz at 100-kHz offset at 10 GHz, which is reduced by about 10 dB compared to that of the conventional one.