Year: 2026
Type: preprint
Abstract: Negative-resistance microwave oscillators can simultaneously sustain autonomous oscillations and coherently scatter RF signals, enabling active reflection beyond conventional linear amplification. Here we demonstrate large resonant reflection gain from synchronization-induced phase localization in a self-sustained tunnel-diode oscillator operating near 2.96 GHz. Weak resonant RF injection drives a transition from a broadband free-running state to a phase-localized narrowband reflected carrier. The resulting coherent reflected carrier reaches 83.1±0.8dB relative to the injected signal and is accompanied by order-of-magnitude linewidth collapse, nonlinear injection pulling, and a synchronization bandwidth of 15.84 kHz. Time-resolved spectrograms directly highlight injection locking and frequency entrainment, while noisy Stuart–Landau simulations reproduce the observed spectral concentration and detuning-dependent gain roll-off near the Hopf instability. Artificially increasing phase diffusion with broadband bias noise suppresses the reflected enhancement, supporting synchronization-induced quenching of phase fluctuations as the mechanism underlying the large coherent reflection gain.
Source: arXiv (Cornell University)
Authors: Arumugam, Darmindra, Bush, Jack, Feyissa, Brook
Institutions: California Institute of Technology, Jet Propulsion Laboratory
Language: English
Subfield: Statistical and Nonlinear Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G2676722403, G3648211085, G830101876
OpenAlex ID: W7203586218