磁阻传感器的多相滤波模型

提出了一种新颖的倾斜多相滤波(SMPF)磁阻器件设计模型,采用这种SMPF模型设计的磁阻传感器,可以滤去n(n=2,3,4…[V])次谐波;倾斜相角Δθ=2π/3时,波形畸变最小;具有正弦输出的编码器被研制,实验发现当倾角φ=5°[p=0.8mm,l=3mm,Δθ=2π/3]时输出为正弦波,与SMPF理论值φ=4.904°相吻合,这一结果可以广泛于磁阻传感器领域。     

偏压对溅射ITO膜载流子浓度和迁移率的影响

研究了基体偏压对 ITO 膜载流子浓度和迁移率影响的机理,并就载流子浓度和迁移率随偏压变化的实验结果与理论结果作了比较,两者基本吻合。获得了n_e=3.2×10~(20)cm~(-3),U_H=50cm~2V~(-1)s~(-1)的 ITO 膜。     

Coupled THz Waveguide Utilizing Surface Plasmon Polaritons on Thin Dielectric Slab Sandwiched between Two Corrugated Metallic Claddings

We present a comprehensive experimental study of terahertz （THz） wave propagation utilizing surface plasmon polaritons （SPPs） on the interfaces of a thin dielectric core layer sandwiched between two corrugated metallic claddings. THz wave impinges on the structured surfaces at normal incidence. Long-lasting oscillation propagation features are observed in the temporal waveform after traveling through the periodic arrays. The enhanced THz transmission can be achieved due to the coupling between incident waves to SPPs at the bottom and top interfaces. The finite element method is used to simulate the field distribution and the transmission mode in the waveguide. The hybrid waveguide with low absorption has great potential applications in THz integrated devices.     

制备工艺对PZT/NiCuZn复合材料电磁性能的影响

采用sol-gel法、固相反应法和掺杂的sol-gel法三种制备工艺,制备了PZT与NiCuZn质量比为3:7和4:6的两种铁电/铁磁复合材料。研究了不同制备工艺对低温烧结复合材料显微结构和电磁性能的影响。结果表明:三种制备工艺都能很好地实现900℃低温烧结,且所制复合材料的ρv大于5.2g·cm–3,μi大于19,Q值大于265,ε′大于45。相对而言,掺杂的sol-gel法所制材料性能最好,其次是固相反应法,再次是sol-gel法。但是,从适于批量生产以及降低成本的角度考虑,固相反应法更符合实际。     

磁电复合材料的研究现状及展望

介绍了国内外磁电复合材料的研究历史和制备方法,如混相法,铁电/铁磁材料层状复合法。探讨了磁电复合材料应用研究中亟待解决的问题,指出了今后的发展趋势是改进复合材料的设计方法、制备工艺和集成器件应用。     

射频宽带变压器两种实现方式的研究

实现射频宽带变压器的方式有低功率线性变压器和传输线变压器两种.该文从传统变压器理论和传输线理论入手,分析了影响变压器频率响应曲线的因素,提出设计射频宽带变压器的通用方法,并实际制作了这两种变压器,验证了方法的有效性,通过对测试结果的分析和比较,得到一些改善器件性能的有效方法.     

Co_2O_3-Bi_2O_3掺杂对NiCuZn/PZT复合材料性能的影响

首先用sol-gel法制得Pb0.95Sr0.05(Zr0.52Ti0.48)O3(PZT)纳米粉料,然后用固相法制备NiCuZn/PZT铁氧体/陶瓷复合材料。研究了Co2O3-Bi2O3复合掺杂对复合材料性能的影响。结果表明:当w(Bi2O3)=2.5%时,引入适量的Co2O3掺杂不仅可使品质因数提高到235,同时介电常数和烧结体密度分别提高到55和5.01g/cm3,介质损耗下降到0.065。其电磁性能满足电容器和电感器的制作要求,有望成为用于叠片滤波器的电感、电容复合双性材料。     

Large Magnetoresistance Based on Double Spin Filter Tunnel Barriers

We propose and theoretically analyse a double magnetic tunnel device that takes advantages of the spin filter effect. Two magnetic tunnel barriers are formed by different spin filters which have different barrier heights. The magnetoresistance of the device is low （high） when the magnetic moments of the two spin filters are parallel （antiparallel）. We present a theoretical calculation of the magnetoresistance based on electric tunnel effect. In addition, the effect of the difference barrier heights and exchange splitting energies between the two spin filters are also analysed in detail. The numerical results show that the spin filter in this configuration gives a magnetoresistance larger than that with standard magnetic tunnel junctions.     

An Artificially Garnet Crystal Materials Using In Terahertz Waveguide

A hypothesis is brought forward that the materials with low propagation loss in both optical and microwave band may exhibit good performance in terahertz （THz） band because THz wave band interspaces those two wave bands. For the purpose-of exploring a kind of low-loss material for THz waveguide, Lu2.1Bi0.9Fe5O12（LuBiIG） garnet films are prepared by liquid phase epitaxy （LPE） method on a gadolinium gallium garnet （GGG） substrate from lead-free flux because of the good properties in both optical and microwave bands. In microwave band, the ferromagnetic resonance （FMR） linewidth of the film 2△H = 2.8-5.1Oe; in optical band, the optical absorption coefficient is 600cm^-1 at visible range and about 100-170cm^-1 when the wavelength is longer than 800nm. In THz range, our hypothesis is well confirmed by a THz-TDS measurement which shows that the absorbance of the film for THz wave is 0.05-0.3 cm 1 and the minimum value appears at 2.3 THz. This artificial ferromagnetic material holds a great promise for magnetic field tunable THz devices such as waveguide, modulator or switch.     

硅基金字塔结构光控太赫兹调制器

提出一种硅基金字塔结构光控太赫兹波调制器。通过化学刻蚀方法在高阻硅基底形成微米级的金字塔结构,研究该结构与高阻硅片对激光的反射率及对太赫兹的调制情况。实验表明,金字塔结构可有效降低激光反射率,提升激光利用率,并且通过增加太赫兹波调制面积,达到显著增强太赫兹波的调制效果,其调制深度达到90%以上。该硅基金字塔结构光控调制器可在极低的激光功率下工作,具有宽带、大幅度调制的特点,在太赫兹成像领域具有重要应用价值。