双环推挽型高线性M-Z光强调制器特性研究

对损耗影响下的双环推挽（TRAPP）型马赫一曾德（M-Z）光调制器的线性特性进行了研究。分析表明,存在损耗时,设计特定的光微环与M-Z干涉臂间的耦合大小,并控制偏置点,总可以获得2次与3次高阶项为零的调制曲线;当微环1周损耗小于5dB时,线性范围总是可以达到90％以上;当损耗过大时,导致基于微环的全通滤波器的相位响应受限,虽然调制曲线在自身范围内依然保持高的线性度,但调制曲线固有的调制深度将限制整体线性范围。     

掺钛蓝宝石固体激光谐振腔的稳定特性研究

运用ABCD传输矩阵理论对掺钛蓝宝石固体激光谐振腔的稳定特性进行了研究,得出了该类激光谐振腔的稳区解析解,讨论了谐振腔的像散补偿、束腰大小和位置与腔参数的关系等问题.     

双阻带特性的超宽带单极子天线设计

设计了一种具有双阻带特性的超宽带单极子天线,对嵌入开路微带谐振器和边缘相似谐振器进行了分析.利用这两种谐振器可以分别在Wimax（3.33～6 GHz ）和WLAN（ 5.15～5.85 GHz）两个频段产生阻带.通过改变天线几何尺寸,可以分别对阻带的中心频率和带宽独立控制.天线利用印刷线路板（PCB）技术加工实现,并对其阻带特性、回波损耗、辐射方向图、辐射效率和峰值增益进行了测试,测试结果和仿真结果吻合很好.     

One and two port piezoelectric higher order contour-mode MEMS resonators for mechanical signal processing

This paper reports on the design, fabrication and testing of novel one and two port piezoelectric higher order contour-mode MEMS resonators that can be employed in RF wireless communications as frequency reference elements or arranged in arrays to form banks of multi-frequency filters. The paper offers a comparison of one and two port resonant devices exhibiting frequencies approximately ranging from 200 to 800 MHz, quality factor of few thousands (1000–2500) and motional resistances ranging from 25 to 1000 Ω. Fundamental advantages and limitations of each solution are discussed. The reported experimental results focus on the response of a higher order one port resonator under different environmental conditions and a new class of two port contour resonators for narrow band filtering applications. Furthermore, an overview of novel frequency synthesis schemes that can be enabled by these contour-mode resonators is briefly presented.     

角锥棱镜腔Cr4+:YAG被动调Q内腔式光参量振荡器

通过对角锥棱镜腔实现KTPⅡ类非临界相位匹配光参量振荡的理论分析,发现腔内存在特殊偏振方位角的本征模式,其满足Ⅱ类非临界相位匹配条件。实验上不但实现了该腔的Cr4 ∶YAG被动调Q内腔式光参量振荡器(OPO)运转,而且得到了优于平-平腔的转换效率,改善了信号光的稳定性。分析了Cr4 ∶YAG初始透过率和腔内功率密度的关系,实验获得不同Cr4 ∶YAG初始透过率、抽运能量和信号光能量的关系曲线。通过腔内功率密度的优化,电光效率高达0.25%,设计出结构紧凑、小型高效的工程实用光参量振荡器器件,抽运能量阈值为4.7 J,输出能量为11.8 mJ,脉宽为6.9 ns,发散角为7 mrad,能量稳定性为5%。     

解读无线通信设备电磁兼容系列标准通用要求

介绍了无线通信设备电磁兼容性要求和测量方法的通用技术要求,如试验布置、免测频段、窄带响应、性能判据等,并对复合无线电设备、多模终端的电磁兼容测试导则进行了解读。     

计算共轴球面腔等价腔长时应注意的问题

本文通过相关例子,指出在计算共轴球面腔等价腔长时容易出现的错误,分析错误原因,并对易混淆的等价腔长、光学腔长及几何腔长三个概念进行了辨析.对等价腔长的概念进行了诠释,即共轴球面腔的等价腔长等于与该腔等效的G参数等价腔的空腔长度.这有助于学生对上述概念的理解和掌握.     

梯度折射率光纤透镜的薄透镜等效分析

从等效薄透镜的角度对热扩束（TEC）光纤＋无芯光纤＋梯度折射率（GRlN）光纤透镜进行了细致的理论分析，其中TEC光纤调整输入高斯光束的束腰半径，无芯光纤控制束腰和薄透镜间的距离，GRIN光纤两主面之间部分等效为薄透镜，其焦距由光纤的折射率分布参数g决定。推导了出射高斯光束的束腰半径和工作距离的解析表达式，进而对该光纤透镜做了数值模拟，讨论了无芯光纤和GRIN多模光纤的长度对光纤透镜参数的影响。当GRIN光纤透镜用作准直器使用时，其最大束腰直径可达到80／1m，可将单模光纤的远场发散角压缩8倍；用于MEMS器件时，最大工作距离可达到3mm。     

HF high power electronically tunable helical resonator filter

A novel design of a high power electronically tunable helical resonator filter suitable for applications in HF radio communication is proposed. The helical resonator is loaded in the middle of the helix and the tuning element is set outside the cavity. Theoretical analysis and experimental verification are demonstrated.     

Electrically Enhanced Readout System for a High‐Frequency CMOS‐MEMS Resonator

The design of a CMOS clamped‐clamped beam resonator along with a full custom integrated differential amplifier, monolithically fabricated with a commercial 0.35 μm CMOS technology, is presented. The implemented amplifier, which minimizes the negative effect of the parasitic capacitance, enhances the electrical MEMS characterization, obtaining a 48 × 10⁸ resonant frequency‐quality factor product (Q×f_res) in air conditions, which is quite competitive in comparison with existing CMOS‐MEMS resonators.