We design and fabricate 4H-SiC UV avalanche photodiodes （APDs） ~qth positive beveled mesa, which exhibit low leakage current and high avalanche gain when working in the Geiger mode. The single photon counting perfor...We design and fabricate 4H-SiC UV avalanche photodiodes （APDs） ~qth positive beveled mesa, which exhibit low leakage current and high avalanche gain when working in the Geiger mode. The single photon counting performance of the SiC APDs is studied by using a passive-quenching circuit. A new method to determine the exact breakdown voltage of the APD is proposed based on the initial emergence of photon count pulses. The photon count rate and dark count rate of the APD are also evaluated as a function of quenching resistance.展开更多
基于模型的目标分解是极化合成孔径雷达(SAR)的一个重要应用,基于模型目标分解依赖于极化数据仅能获得各散射机制的能量信息。该文将基于模型的分解技术应用到π/4模式的简缩极化干涉SAR(C-Pol In SAR)数据中,对互相关矩阵进行分解,在...基于模型的目标分解是极化合成孔径雷达(SAR)的一个重要应用,基于模型目标分解依赖于极化数据仅能获得各散射机制的能量信息。该文将基于模型的分解技术应用到π/4模式的简缩极化干涉SAR(C-Pol In SAR)数据中,对互相关矩阵进行分解,在获得各散射机制功率的同时获得对应的散射相位中心。该文首先推导出3种散射机制π/4简缩极化SAR干涉观测下散射模型,然后运用数值计算方法进行目标分解,最终求解出各散射机制的功率贡献及相位中心高度信息。仿真数据验证了该算法的有效性,分析了不同波段及不同地表参数对分解结果的影响。展开更多
基金Supported by the National Basic Research Program of China under Grant Nos 2011CB301900 and 2011CB922100the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘We design and fabricate 4H-SiC UV avalanche photodiodes （APDs） ~qth positive beveled mesa, which exhibit low leakage current and high avalanche gain when working in the Geiger mode. The single photon counting performance of the SiC APDs is studied by using a passive-quenching circuit. A new method to determine the exact breakdown voltage of the APD is proposed based on the initial emergence of photon count pulses. The photon count rate and dark count rate of the APD are also evaluated as a function of quenching resistance.
文摘基于模型的目标分解是极化合成孔径雷达(SAR)的一个重要应用,基于模型目标分解依赖于极化数据仅能获得各散射机制的能量信息。该文将基于模型的分解技术应用到π/4模式的简缩极化干涉SAR(C-Pol In SAR)数据中,对互相关矩阵进行分解,在获得各散射机制功率的同时获得对应的散射相位中心。该文首先推导出3种散射机制π/4简缩极化SAR干涉观测下散射模型,然后运用数值计算方法进行目标分解,最终求解出各散射机制的功率贡献及相位中心高度信息。仿真数据验证了该算法的有效性,分析了不同波段及不同地表参数对分解结果的影响。
