铷原子频标的频率稳定度指标在很大程度上取决于物理系统所用微波腔的特性.本文设计了一款内径为40 mm的开槽管微波腔，并在此基础上实现了一款铷频标物理系统.计算和实验测量的微波腔内微波场的方向因子分别为0.87和0.91，表明微波场磁力线与量子化轴方向高度平行.测量了物理系统的鉴频斜率和散弹噪声，据此预计这种微波腔可满足设计稳定度优于2×10^-13τ^-1/2铷频标的需求.

The frequency stability of a passive rubidium atomic frequency standard (RAFS) largely depends on the performance of the microwave cavity used in the physics package. In this paper, a large-size slotted tube microwave cavity with an inner diameter of 40 mm, as well as the physics package based on this cavity, were designed and built. Theoretical calculations and experimental results showed that the magnetic lines inside this cavity were highly parallel to the quantization axis. The frequency discrimination slope and the shot noise of the physics package were measured. The results showed that the cavity could be used to realize an RAFS with frequency stability of 2×10^-13τ^-1/2.