高功率880nm激光芯片的结构设计,均采用大光学腔和小于0.62cm-1的低内损,并通过MOCVD(Metal-organic Chemical Vapor Deposition)工艺实现这种结构的外延。通过一系列标准和特殊制造工艺,实现了200μm发射器宽度和4mm腔长激光芯片。在P...高功率880nm激光芯片的结构设计,均采用大光学腔和小于0.62cm-1的低内损,并通过MOCVD(Metal-organic Chemical Vapor Deposition)工艺实现这种结构的外延。通过一系列标准和特殊制造工艺,实现了200μm发射器宽度和4mm腔长激光芯片。在P面朝下贴装在AlN陶瓷基板上后,测试880nm激光器的阈值电流为1.1A,斜率效率为1.11W/A,中心工作波长为11A时为880.8nm,光谱半高宽(FWHM)为2.2nm。在16A的连续电流和20°C的冷却水温下进行加速老化试验,老化时间达到2000h时无故障。根据ISO/FDIS 17526的Arrhenius模型,MTTF(Mean time to failure)计算为20万小时。展开更多
基于功率放大器的动态负载线理论,参照Si和GaAs功率器件的降额准则,总结工程应用经验得到了GaN功率器件不同等级的电压降额系数,即I级、II级、III级降额时击穿电压应分别大于工作电压的3.14倍、2.75倍、2.44倍。通过GaN功率器件可靠性...基于功率放大器的动态负载线理论,参照Si和GaAs功率器件的降额准则,总结工程应用经验得到了GaN功率器件不同等级的电压降额系数,即I级、II级、III级降额时击穿电压应分别大于工作电压的3.14倍、2.75倍、2.44倍。通过GaN功率器件可靠性试验数据预估了器件在正常工作条件下的平均失效时间(MTTF),并参考多家半导体厂家关于GaN器件结温与可靠性关系的统计数据,得出了GaN功率器件不同等级的结温降额数值,即I级、II级、III级降额结温分别为135~140、160和180℃,降额系数分别为0.6~0.62、0.71和0.8。选用一款X波段20 W GaN内匹配功率器件进行验证,在提出的I级降额条件下,该器件已安全工作超18000 h。提出的降额条件对GaN功率器件的设计和应用具有一定的指导意义。展开更多
Ga N微波功率管在基站通信等领域具有重要应用,其可靠性对相关设备的性能有直接影响。利用红外热像分析技术测量器件的峰值结温,基于专用射频加速老化试验系统,在频率为2.85 GHz、输入功率为40.5 d Bm、脉冲宽度为3 ms、占空比为30%的...Ga N微波功率管在基站通信等领域具有重要应用,其可靠性对相关设备的性能有直接影响。利用红外热像分析技术测量器件的峰值结温,基于专用射频加速老化试验系统,在频率为2.85 GHz、输入功率为40.5 d Bm、脉冲宽度为3 ms、占空比为30%的脉冲射频工作条件下,对S波段Ga N微波功率管进行了壳温为150℃的加速寿命试验。应用Arrhenius模型对试验结果进行了分析和计算,推导出该器件在壳温为90℃的工作条件下其平均失效时间可达2.97×106h。结果表明,采用此试验方法可以用来评估第三代Ga N微波功率器件的可靠性水平。展开更多
To Integrate the capacity of sensing, communication, computing, and actuating, one of the compelling technological advances of these years has been the appearance of distributed wireless sensor network (DSN) for infor...To Integrate the capacity of sensing, communication, computing, and actuating, one of the compelling technological advances of these years has been the appearance of distributed wireless sensor network (DSN) for information gathering tasks. In order to save the energy, multi-hop routing between the sensor nodes and the sink node is necessary because of limited resource. In addition, the unpredictable conditional factors make the sensor nodes unreliable. In this paper, the reliability of routing designed for sensor network and some dependability issues of DSN, such as MTTF (mean time to failure) and the probability of connectivity between the sensor nodes and the sink node are analyzed. Unfortunately, we could not obtain the accurate result for the arbitrary network topology, which is #P-hard problem. And the reliability analysis of restricted topologies clustering-based is given. The method proposed in this paper will show us a constructive idea about how to place energy-constrained sensor nodes in the network efficiently from the prospective of reliability.展开更多
文摘高功率880nm激光芯片的结构设计,均采用大光学腔和小于0.62cm-1的低内损,并通过MOCVD(Metal-organic Chemical Vapor Deposition)工艺实现这种结构的外延。通过一系列标准和特殊制造工艺,实现了200μm发射器宽度和4mm腔长激光芯片。在P面朝下贴装在AlN陶瓷基板上后,测试880nm激光器的阈值电流为1.1A,斜率效率为1.11W/A,中心工作波长为11A时为880.8nm,光谱半高宽(FWHM)为2.2nm。在16A的连续电流和20°C的冷却水温下进行加速老化试验,老化时间达到2000h时无故障。根据ISO/FDIS 17526的Arrhenius模型,MTTF(Mean time to failure)计算为20万小时。
文摘基于功率放大器的动态负载线理论,参照Si和GaAs功率器件的降额准则,总结工程应用经验得到了GaN功率器件不同等级的电压降额系数,即I级、II级、III级降额时击穿电压应分别大于工作电压的3.14倍、2.75倍、2.44倍。通过GaN功率器件可靠性试验数据预估了器件在正常工作条件下的平均失效时间(MTTF),并参考多家半导体厂家关于GaN器件结温与可靠性关系的统计数据,得出了GaN功率器件不同等级的结温降额数值,即I级、II级、III级降额结温分别为135~140、160和180℃,降额系数分别为0.6~0.62、0.71和0.8。选用一款X波段20 W GaN内匹配功率器件进行验证,在提出的I级降额条件下,该器件已安全工作超18000 h。提出的降额条件对GaN功率器件的设计和应用具有一定的指导意义。
基金This work was supported by National Defence Advanced Research Fund .Serial No.5141604010HT0117
文摘To Integrate the capacity of sensing, communication, computing, and actuating, one of the compelling technological advances of these years has been the appearance of distributed wireless sensor network (DSN) for information gathering tasks. In order to save the energy, multi-hop routing between the sensor nodes and the sink node is necessary because of limited resource. In addition, the unpredictable conditional factors make the sensor nodes unreliable. In this paper, the reliability of routing designed for sensor network and some dependability issues of DSN, such as MTTF (mean time to failure) and the probability of connectivity between the sensor nodes and the sink node are analyzed. Unfortunately, we could not obtain the accurate result for the arbitrary network topology, which is #P-hard problem. And the reliability analysis of restricted topologies clustering-based is given. The method proposed in this paper will show us a constructive idea about how to place energy-constrained sensor nodes in the network efficiently from the prospective of reliability.
