应用于相干布居囚禁原子钟的低相位噪声微波频率综合器

相干布居囚禁(CPT)原子钟作为微波原子钟的一种类型,由于不需要微波谐振腔即可实现微波探询,可极大降低体积和功耗,从而实现芯片级、低功耗的原子钟。CPT原子钟性能指标的主要限制因素之一是微波综合器的相位噪声,为了提升CPT原子钟的性能,研制了一种应用于CPT原子钟的低相位噪声频率综合器。实验结果表明,频率综合器在200Hz处的绝对相位噪声为108dBc/Hz。微波综合器由于Dick效应对原子钟频率稳定度的限制为8.2×10^-14,可以完全满足CPT原子钟的性能指标要求。此频率综合器也可更广泛地用于其它高性能微波原子精密测量系统以及计量标准器。

Research for the Resistively Loaded Monocone TEM Cell

A novel resistively loaded monocone with wide bandwidth and low reflectivity was proposed in this paper. To solve the time window caused by limited length, eight non-inductance resistors networks were applied for the distributed impedance end-loading. Reflections occurred from either the end of cone or the edge of the ground plane was reduced significantly and the operational frequency band-width was widen effectively after loading, especially for the low frequency. The result shows that the measured maximum S11 is less than -17dB from DC to 1GHz for the resistively loaded monocone with length of 1.5m, which broken the time window constraints caused by limited cone length and greatly extended the application for pulse E-field calibration. Correspondingly, the calibration range of measuring system is pushed from ultra-short pulse limited by time window to NEMP with more than 20ns pulse width, as well as for the gain and bandwidth measurement of regular antenna.