一种线性可控全集成SiGe BiCMOS驱动放大器

基于Jazz工艺,提出一种线性可控全集成Si Ge Bi CMOS驱动放大器（DRA）,实现多种可调功率增益放大作用。电路采用全差分共射共基结构,通过调节CMOS电流镜偏置电路和Si Ge-HBT管尺寸以及3bit控制位,实现1d B步长的可控增益。仿真结果显示：在10μA的带隙基准电流源以及3.3V的电源电压下,DRA实现八种可调功率增益,其线性度指标即输出1d B压缩点OP1d B〉3d Bm,电路供电电流〈10m A,且电路输入输出匹配良好（S11与S22均小于-19d B）。     

Novel circularly-polarized ceramic dielectric resonator antenna excited by a corner-cut square patch

A ceramic dielectric resonator antenna excited by a corner-cut square patch for the circularly-polarized operation is introduced. The effect of patch size and cut size is investigated, showing that the resonant frequency of the antenna can be changed by simply changing the patch size. The reflection, axial ratio, and radiation characteristics of the antenna are found. Measurements were carried out to verify the design. The antenna is compact in structure, which is attractive in the application as the satellite communication terminals.     

移动多媒体广播技术在移动学习中的应用探索

详细介绍了移动多媒体广播(China Mobile Multimedia Broadcasting,CMMB)的含义、发展历程、系统架构和核心技术,以及现代远程教育新的发展趋势--移动学习(mobile-Learning)的含义和特点.对于将移动多媒体广播技术用于移动学习的优势进行了初步的分析.