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计算机网络对人类社会方方面面产生了巨大深刻影响,为人们提供获取信息的便捷途径。共享ADSL宽带连接使局域网接入互联网变得廉价、有效。本文就通过共享ADSL宽带接入互联网有关问题作简单探讨。 相似文献
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Design of a reentrant double staggered ladder circuit for V-band coupled-cavity traveling-wave tube 下载免费PDF全文
The reentrant double staggered ladder slow-wave structure is employed in a high-power V-band coupled-cavity traveling-wave tube. This structure has a wide bandwidth, a moderate interaction impedance, and excellent thermal dissipation properties, besides the easy fabrication. A well-matched waveguide coupler is proposed for the structure. Combining the design of attenuators, a full-scale three-dimensional circuit model for the V-band coupled-cavity traveling-wave tube is constructed. The electromagnetic characteristics and the beam--wave interaction of this structure are investigated. The beam current is set to be 100 mA, and the cathode voltage is tuned from 16.8 kV to 15.8 kV. The calculation results show that this tube can produce a saturated average output power over 100 W with an instantaneous bandwidth greater than 1.25 GHz in the frequency ranging from 58 GHz to 62 GHz. The corresponding gain and electronic efficiency can reach over 32 dB and 6.5%, respectively. 相似文献
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采用交错双栅结构,结合带状电子注,研究了一种工作在140 GHz频段的大功率行波管. 本振模数值计算表明该结构具有良好的色散特性和耦合阻抗.针对所采用的慢波结构, 提出了慢波过渡结构、输入输出耦合器和集中衰减器,保证了行波管的良好工作. 利用三维大信号模拟计算的方法得到的结果显示,当电子注直流功率为5.115 kW,输入信号功率为0.1 W时, 所研究的行波管能在132-152 GHz范围内提供大于300 W的峰值功率,其中在138 GHz时得到最大功率546 W, 对应增益为37.37 dB.当在0.027-0.46 W内调节输入信号功率,可以保持该行波管在128-152 GHz 频带内得到大于440 W的峰值功率,对应的电子效率大于8.6%. 结果显示该行波管将在大功率短毫米波领域具有重要意义和潜在应用价值. 相似文献
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将矩形交错双栅结构作为慢波电路并提出与之配套的过渡结构和输出耦合器,设计了利用带状电子注工作在W波段的返波振荡器。提出的过渡结构和耦合器解决了该类直波导型器件的信号传输衰减大、反射强等难题。相对于传统圆形电子注器件,该器件得到了较大的功率提升。利用三维粒子模拟计算的方法,在电流12 mA时通过调节工作电压,在92~98 GHz频带内得到了数W的稳定平均功率输出,信号中心频率非常接近设计频率,且单色性好,谐波分量小。 相似文献
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We explore the entropy uncertainty for qutrit system under non-Markov noisy environment and discuss the effects of the quantum memory system and the spontaneously generated interference(SGI)on the entropy uncertainty in detail.The results show that,the entropy uncertainty can be reduced by using the methods of quantum memory system and adjusting of SGI.Particularly,the entropy uncertainty can be decreased obviously when both the quantum memory system and the SGI are simultaneously applied. 相似文献
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Design of a re-entrant double-staggered ladder circuit for V-band coupled-cavity traveling-wave tubes 下载免费PDF全文
The re-entrant double-staggered ladder slow-wave structure is employed in a high-power V-band coupled-cavity traveling-wave tube. This structure has a wide bandwidth, a moderate interaction impedance, and excellent thermal dissipation properties, as well as easy fabrication. A well-matched waveguide coupler is proposed for the structure. Combining the design of attenuators, a full-scale three-dimensional circuit model for the V-band coupled-cavity traveling-wave tube is constructed. The electromagnetic characteristics and the beam-wave interaction of this structure are investigated. The beam current is set to be 100 mA, and the cathode voltage is tuned from 16.8 kV to 15.8 kV. The calculation results show that this tube can produce a saturated average output power over 100 W with an instantaneous bandwidth greater than 1.25 GHz in the frequency ranging from 58 GHz to 62 GHz. The corresponding gain and electronic efficiency can reach over 32 dB and 6.5%, respectively. 相似文献
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提出了一种新型的菱形微带曲折线慢波结构。该结构可适用于低电压、宽带宽、中等功率水平的高效率毫米波行波管。和传统的慢波结构相比,微带曲折线是一种平面结构,因此其加工工艺可采用2维微细加工技术。该结构可以用带状电子束进行注-波互作用,并且不需要额外的电子束通道。给出了菱形微带曲折线慢波结构在140 GHz的色散曲线和注-波互作用模拟分析。研究结果显示:在输入功率为40 mW,带状电子束的电流和工作电压分别为90 mA和7 kV的条件下,该微带曲折线行波管可以获得数十W功率输出,互作用效率可达14.3%,瞬时3 dB带宽为18 GHz(132~150 GHz)。 相似文献