Work

Microwave Oscillator Based on Two Optimally Tuned YIG Filters

Year: 2025

Type: article

Abstract: We report a novel X-band loop oscillator, whose resonator is formed from two optimally tuned commercial Yttrium-Iron-Garnet (YIG) filters. We call this a Λ-resonator, owing to the characteristic Λ-shape of its amplitude transfer function. At offset frequencies greater than 70 Hz, oscillator phase noise is limited by the contribution from the amplifier, as described by Leeson's Model. The effective Q-factor of the Λ-resonator (2.6 ×10 3) is determined by the slope of its phase transfer function on resonance, which is directly proportional to the group delay of the filters. With off-the-shelf components, we achieve SSB phase noise of-120.6 dBc/Hz at 100 kHz offset for an oscillation frequency of 9.2 GHz. This points to the potential for improvements with custom built filters optimized for high group delay. We further investigate noise sources, including power-to-frequency conversion with a novel, highly sensitive technique.

Source: IEEE Transactions on Microwave Theory and Techniques

DOI: 10.1109/tmtt.2025.3617506

Authors: Robert C. Crew, Eugene N. Ivanov, Graeme Flower, Michael E. Tobar, Maxim Goryachev

Institution: The University of Western Australia

Language: English

Topic: Radio Frequency Integrated Circuit Design

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,645

Funder: Australian Research Council