Theoretical Analysis of Relationships between Resonator Coupling Coefficient and Phase Noise in Microwave Negative-Resistance Oscillators

Ken'ichi HOSOYA
Shin'ichi TANAKA
Kazuhiko HONJO

IEICE TRANSACTIONS on Electronics   Vol.E87-C    No.12    pp.2132-2142
Publication Date: 2004/12/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Microwaves, Millimeter-Waves
microwave oscillators,  millimeter wave oscillators,  phase noise,  resonators,  Q factor,  circuit modeling,  

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A new analytical approach which reveals relationships between resonator parameters (unloaded Q-factor, coupling coefficient, and loaded Q-factor) and phase noise in microwave negative-resistance oscillators is presented. On the basis of Kurokawa's theory, this approach derives analytical expressions for the phase noise as a function of the resonator parameters (with particular emphasis on the coupling coefficient). Two types of negative-resistance oscillators--classified according to the manner in which the resonator is used in a circuit--are analyzed. These analyses use realistic circuit configurations and design procedures. The passive network connecting the active device and the resonator, which is shown to have important effects on the above-mentioned relationship, is taken into account. Validity of the new approach is verified through harmonic-balance simulations. The presented analytical approach can provide useful guidelines for choosing the resonator parameters, especially the value of the coupling coefficient, when designing microwave negative-resistance oscillators.