Broadband Frequency Reconfigurable Resonator for Rydberg Atomic Enhancement Sensing

Resonant structures provide a promising approach to significantly enhance the sensing sensitivity of Rydberg atomic receivers. However, conventional resonators predominantly operate at fixed frequencies, thereby constraining the intrinsic broadband response capabilities of Rydberg atoms. This study introduces a broadband frequency reconfigurable resonator (BFRR) engineered to augment sensitivity while preserving the broadband characteristics of atomic receivers. By employing varactor diodes to dynamically adjust equivalent capacitance and PIN diodes to selectively activate distinct inductive branches, the BFRR achieves continuous electronic tuning from 231 to 586 MHz, corresponding to a relative bandwidth of 86.9%. Inoff-resonant atomic heterodyne configurations, the integration of the BFRR enhances sensitivity by nearly two orders of magnitude across the tuning range, attaining a sensitivity of 30.4 (nV/cm)/$\sqrt{\text {H}z}$at 564.2 MHz. This advancement significantly improves both the sensitivity and broadband adaptability of Rydberg atomic receivers, thereby offering essential support for progress in quantum electrometry.