反射面天线极化选择栅的设计

文章介绍了反射面天线极化选择栅的设计方法:首先将金属栅条与介质层去耦,二者独立设计;然后,对极化选择栅全模型采用三维电磁场仿真。该方法物理概念清晰,且只需要对最终模型进行三维电磁仿真,计算量小。最后,设计了一个Ku频段的极化选择栅,仿真与测试结果吻合良好,验证了文章方法的有效性。

基于多层线极化选择栅的天线极化重构设计

提出了一种基于多层线极化选择栅的天线极化重构设计方法,在阵列天线上加载多层线极化栅,当天线阵面固定不动时,通过旋转极化选择栅实现线天线极化重构。分析了线极化选择栅层间距对天线辐射性能的影响,研究了在天线极化重构情况下极化栅的层间距和层数对天线增益的影响。对Ku波段阵列天线和三层线极化选择栅进行了加工和测试,测试结果与仿真结果基本一致。天线法向辐射时,极化旋转90°的增益损失约为0.62 dB~1.68 dB。天线波束扫描时,增益损失有所增大。当线极化选择栅为四层时,天线在0~45°扫描角范围内,极化旋转90°的增益损失减小至0.8 dB,旁瓣抬升小于2 dB。文中设计的多层线极化选择栅结构具有可极化重构、损耗低和角度稳定性好的优点,为天线实现线极化重构和极化匹配提供了一种新方法。

选择栅共享式分栅闪存单元特性研究

阐述一种新型的选择栅共享式分栅闪存,该闪存单元具有优异的耐久性,数据保持,抗编程串扰特性,同时该闪存单元具有面积小,工艺成本低,可微缩性强等特点。研究对该闪存单元的耐久性,数据保持,编程串扰等特性,探讨读取、擦写和编程操作电压的优化方案。

静态电阻应变测量中若干技术问题的讨论

从理论方面讨论、分析了在静态应力应变测量中影响测量准确性的几个电测技术问题,包括应变计栅长选择、应变片粘贴方向、应变计横向效应、长导线影响及其修正。

PMOS OTP的器件结构、工作原理以及实现方法

OTP(one time programmable memory)是常见的一种NVM,在有限密度有限性能的嵌入式NVM方面有较多的应用,传统的EEPROM、S0NOS、E-Flash NVM成本昂贵。OTP与CMOS相容的嵌入式NVM技术是当前工业界的成功解决方案,并在诸如模拟技术微调应用中的位元级一直到数据或代码储存的千位元等级取得越来越广泛的应用。其特点在于与CMOS工艺相容,工艺步骤简单、无须额外的光照,成本低廉,可以增强片上系统的功能和灵活性。作者介绍了工业界对于OTP开发的主流类型-利用PMOS来设计OTP的器件结构、基本工作原理。重点分析了在技术研发中遇到的独特的挑战及其解决方案。

新型双异质结双平面掺杂功率PHEMT

设计并制作了双异质结双平面掺杂的 Al0 .2 4 Ga0 .76 As/ In0 .2 2 Ga0 .78As/ Al0 .2 4 Ga0 .76 As功率 PHEMT器件 ,采用双选择腐蚀栅槽结构 ,有效提高了 PHEMT器件的输出电流和击穿电压 .对于 1μm栅长的器件 ,最大输出电流为5 0 0 m A/ mm ,跨导为 2 75 m S/ m m,阈值电压为 - 1 .4 V,最大栅漏反向击穿电压达到了 33V .研究结果表明 ,在栅源间距一定时 ,栅漏间距对于器件的输出电流、跨导和击穿电压有很大关系 ,是设计功率 PHEMT的关键之一 .

A multi-wavelength fiber laser based on superimposed fiber grating and chirp fiber Bragg grating for wavelength selection

In this paper,a new type of multi-wavelength fiber laser is proposed and demonstrated experimentally.Superimposed fiber grating(SIFG) and chirp fiber Bragg grating(CFBG) are used for wavelength selection.Based on gain equalization technology,by finely adjusting the stress device in the cavity,the gain and loss are equal,so as to suppress the modal competition and achieve multi-wavelength lasing at room temperature.The experimental results show that the laser can output stable multi-wavelength lasers simultaneously.The laser coupling loss is small,the structure is simple,and it is convenient for integration,so it can be widely used in dense wavelength division multiplexing(DWDM) system and optical fiber sensors.

Two-step gate-recess process combining selective wet-etching and digital wet-etching for InAIAs/InGaAs InP-based HEMTs

A two-step gate-recess process combining high selective wet-etching and non-selective digital wet-etching techniques has been proposed for InAlAs/InGaAs InP-based high electron mobility transistors （HEMTs）. High etching-selectivity ratio of InGaAs to InA1As material larger than 100 is achieved by using mixture solution of succinic acid and hydrogen peroxide （H202）. Selective wet-etching is validated in the gate-recess process of InA1As/InGaAs InP-based HEMTs, which proceeds and auto- matically stops at the InA1As barrier layer. The non-selective digital wet-etching process is developed using a separately controlled oxidation/de-oxidation technique, and during each digital etching cycle 1.2 nm InAIAs material is removed. The two-step gate-recess etching technique has been successfully incorporated into device fabrication. Digital wet-etching is repeated for two cycles with about 3 nm InAIAs barrier layer being etched off. InP-based HEMTs have demonstrated superior extrinsic trans- conductance and RF characteristics to devices fabricated during only the selective gate-recess etching process because of the smaller gate to channel distance.

Dual-wavelength erbium-doped fiber laser with asymmetric fiber Bragg grating Fabry-Perot cavity

A novel dual-wavelength fiber laser with asymmetric fiber Bragg grating(FBG) Fabry-Perot(FP) cavity is proposed and experimentally demonstrated. A couple of uniform FBGs are used as the cavity mirrors, and the third FBG is used as intracavity wavelength selector by changing its operation temperature. Experimental results show that by adjusting the operation temperature of the intracavity wavelength selector, a tunable dual-wavelength laser emission can be achieved. The results demonstrate the new concept of dual-wavelength lasing with asymmetric FBG FP resonator and its technical feasibility.