Current Location:home > Browse

1. chinaXiv:202001.00047 [pdf]

Review of the high-power vacuum tube microwave sources

徐伟业
Subjects: Electronics and Communication Technology >> Electron Technology

Since the first vacuum tube (X-ray tube) was invented by Wilhelm R?ntgen in Germany, after more than one hundred years of development, the average power density of the vacuum tube microwave source has reached the order of 108 [MW][GHz]2. The maximum power density record was created by the Free Electron Lasers. In the high-power microwave field, the vacuum devices are still the mainstream microwave sources for applications such as scientific instruments, communications, radars, magnetic confinement fusion heating, microwave weapons, etc. The principles of microwave generation by vacuum tube microwave sources include Cherenkov or Smith-Purcell radiation, transition radiation, and Bremsstrahlung. In this paper, the vacuum tube microwave sources were reviewed in order according to the three radiation principles. Among them, the Vircators can produce 22 GW output power in P-band. Vacuum tubes that can achieve continuous-wave operation include Traveling Wave Tubes, Klystrons, Free Electron Lasers, and Magnetrons, with output power up to 1MW. Vacuum tubes that can generate frequencies of the order of 100 GHz and above include Klystrons, Traveling Wave Tubes, Gyrotrons, Backward Wave Oscillators, Magnetrons, Surface Wave Oscillators, Free Electron Lasers, Orotrons, etc. Gyrotrons are very attractive in the millimeter wave and THz fields. The Gyrotrons can output power at the MW level with 3000s pulse width at millimeter wavelengths.

submitted time 2020-01-06 Hits4285Downloads258 Comment 0

2. chinaXiv:201908.00028 [pdf]

High Focusing-reflection Subwavelength Gratings with Uni-traveling-carrier Photodetector for High Responsivity

Chen, Qingtao
Subjects: Electronics and Communication Technology >> Optoelectronics and Laser

High focusing-reflection, non-periodic high-contrast grating integrated with a uni-traveling-carrier photodetector (FR-UTC-PD) is proposed to overcome the bandwidth-responsivity trade-off. The responsivity of the FR-UTC-PD is increased by 36.5% while achieving a 3-dB bandwidth of 18 GHz.

submitted time 2019-08-13 Hits2324Downloads629 Comment 0

3. chinaXiv:201809.00001 [pdf]

基于图像深度学习的无线电信号识别.pdf

周鑫; 何晓新; 郑昌文
Subjects: Electronics and Communication Technology >> Information Processing

本文创新性地提出了一种利用图像深度学习解决无线电信号识别问题的技术思路:首先把无线电信号具象化为一张二维图片,将无线电信号识别问题转化为图像识别领域的目标检测问题;进而充分利用人工智能在图像识别领域的先进成果,提高无线电信号识别的智能化水平和复杂电磁环境下的识别能力。基于该思路,本文提出了一种基于图像深度学习的无线电信号识别算法——RadioImageDet算法。试验结果表明,该算法能有效识别无线电信号的波形类型和时/频坐标,在实地采集的12种、4740个样本的数据集中,识别准确度达到86.03%,mAP值达到77.72,检测时间在中等配置的桌面计算机上仅需33毫秒,充分验证了思路的可行性和算法的有效性。

submitted time 2018-08-31 Hits10731Downloads2059 Comment 0

4. chinaXiv:201709.00002 [pdf]

基于LabVIEW的电路基本实验系统设计

雷宇; 覃林; 顾理
Subjects: Electronics and Communication Technology >> Electron Technology

应用labVIEW软件进行电路基本实验系统的设计,介绍了电路基本实验系统的构成及应用系统进行仿真的方法,并对实验仿真的结果进行了分析。实验结果表明系统能正确的反映出电路的特点,适合在电路实验教学中进行推广。

submitted time 2018-06-25 Hits7421Downloads3417 Comment 3

5. chinaXiv:201704.00218 [pdf]

阵元失效下基于协方差矩阵重构的高分辨测向方法

谭伟杰; 冯西安
Subjects: Electronics and Communication Technology >> Information Processing

摘要:传统子空间类方法依赖于阵列相关矩阵,在阵列中阵元出现失效的情况下,相关矩阵将会秩亏,子空间类方法将会失效。针对该问题,本文从协方差拟合准则出发,将协方差矩阵的 Toeplitz 结构作为约束,基于低秩矩阵重构的原理来恢复协方差矩阵,而后采用子空间类方法来进行目标的方位估计。在阵元失效情况下,该方法能有效重构阵列协方差矩阵,恢复失效阵元的自由度,解决失效阵元情况下高精度目标方位估计的问题。数值仿真表明,该方法在阵元失效条件下,能够恢复损伤阵列到正常阵列条件下的性能,尤其是对于多个目标的情况,该方法表现出更优的性能。

submitted time 2017-04-19 Hits32299Downloads3319 Comment 0

  [1 Pages/ 5 Totals]