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在半导体微纳工艺基础上研究了基于镜像非对称结构超材料太赫兹(THz)滤波器的性能。通过时域有限差分理论,模拟分析了滤波器工作频率下太赫兹电场强度和电流密度在微结构的分布,并阐述了微结构太赫兹波电磁共振的机理。基于太赫兹滤波器电磁损耗机制和微纳加工工艺条件,设计并优化器件开口环结构,使相邻开口环中产生电磁场的干涉相消,减少太赫兹辐射损耗,提高品质因子Q值。采用太赫兹时域光谱(THz-TDS)系统测试了滤波器的太赫兹透射特性,实验结果表明,在工作频率0.923 THz下,镜像非对称结构的平面太赫兹滤波器品质因子达到12.5。同时,研究了太赫兹电场方向对滤波器性能的影响。高Q太赫兹滤波器的研制为制备高速太赫兹电调制器等太赫兹器件提供了重要的实验依据。 相似文献
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Enhancement of terahertz coupling efficiency by improved antenna design in GaN/AlGaN high electron mobility transistor detectors 下载免费PDF全文
An optimized micro-gated terahertz detector with novel triple resonant antenna is presented.The novel resonant antenna operates at room temperature and shows more than a 700% increase in photocurrent response compared to the conventional bowtie antenna.In finite-difference-time-domain simulations,we found the performance of the self-mixing GaN/AlGaN high electron mobility transistor detector is mainly dependent on the parameters L gs(the gap between the gate and the source/drain antenna) and L w(the gap between the source and drain antenna).With the improved triple resonant antenna,an optimized micrometer-sized AlGaN/GaN high electron mobility transistor detector can achieve a high responsivity of 9.45×102 V/W at a frequency of 903 GHz at room temperature. 相似文献
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We present a study of magnetotransport in CrO2/polystyrene (PS) composites over a range of polystyrene concentration (0-30 wt. %). In the experiment, an obvious enhancement in magnetoresistance (MR) is observed at 77K and at room temperature as the hadf-metadlic Cr02 particles are encapsulated with a thin layer of insulating polystyrene. The enhanced MR can be interpreted in terms of spin-dependent intergranular tunnelling with 4-nm-thick PS barrier. Moreover, it is found that the novel PS barrier contributes to room-temperature MR more significantly than that at 77K. Temperature dependence of resistance is good agreement with -T^-1/4 in the temperature range from 77 to 298K. 相似文献
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制备了MnZn铁氧体/SiO2颗粒复合体.研究了磁性颗粒复合体的有效磁导率μ、 比磁化强度σ以及矫顽力Hc随磁性颗粒含量的变化.研究发现,在MnZn铁氧体体积百分含 量为90%—98%的区域,复合体的有效磁导率μ的变化速率发生突变,出现磁渗流现象,从实验得到的体系磁渗流阈值Vc=97.9%.在磁渗流区,矫顽力表现出异常行为.结果表明 ,这种异常行为与复合体微观结构有着密切关系.在磁渗流前,矫顽力Hc的变化主要来 源于磁
关键词:
颗粒复合体
磁渗流
矫顽力 相似文献
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We present a theoretical study on the electric field driven plasmon dispersion of the two-dimensional electron gas(2DEG)in AlGaN/GaN high electron mobility transistors(HEMTs).By introducing a drifted Fermi–Dirac distribution,we calculate the transport properties of the 2DEG in the AlGaN/GaN interface by employing the balance-equation approach based on the Boltzmann equation.Then,the nonequilibrium Fermi–Dirac function is obtained by applying the calculated electron drift velocity and electron temperature.Under random phase approximation(RPA),the electric field driven plasmon dispersion is investigated.The calculated results indicate that the plasmon frequency is dominated by both the electric field and the angle between wavevector and electric field.Importantly,the plasmon frequency could be tuned by the applied source–drain bias voltage besides the gate voltage(change of the electron density). 相似文献
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