Wideband continuously tunable Rydberg atomic receiver: system modeling and parameter dependence analysis

Continuously tunable Rydberg atomic receivers (CT-RARs) based on the AC Stark effect overcome the discrete-frequency limitations of resonant RARs, enabling wideband continuous spectrum coverage. However, existing studies lack a dynamic system model tailored to the CT-RAR, and nonlinear distortion characteristics remain poorly understood, which hinders further optimization of receiver sensitivity. This paper presents theoretical system modeling and performance analysis of the CT-RAR. A small-signal linearized dynamic model is established using time-dependent perturbation theory. We derive closed-form expressions for the dynamic frequency response and prove that the slope of the static response curve is strictly equivalent to the dynamic zero-intermediate-frequency gain. Further, the nonlinear distortion characteristics of the CT-RAR are analyzed using Floquet theory, and the total harmonic distortion under varying signal strengths is evaluated. Finally, we perform a parameter-dependence analysis. The CT-RAR exhibits inherent frequency-selection capability across a wide frequency range. This paper offers a theoretical foundation for guiding the practical design of CT-RARs.