Distributed NGD active circuit for RF-microwave communication

This paper is aimed to the investigation on innovative distributed negative group delay (DNGD) circuits for RF communication. Thanks to the analogy between the lumped and distributed circuits, NGD circuit topologies were identified. By using the S-parameter theory, analysis and synthesis methods of these topologies are proposed. The DNGD circuits developed are mainly comprised of a transistor combined with a series resistance ended by a stub. Then, synthesis relations enabling to determine the NGD circuit parameters from the desired NGD and gain values are established. As application, an active phase shifter (PS) operating independently with the frequency based on the cascade of PGD and NGD devices was synthesized. First, an NGD PS with transmission phase of (135 ± 5)° around 2.56 GHz over the bandwidth of about 1.02 GHz was obtained. Then, a two-stage DNGD PS exhibiting 90° with ±10° flatness from 4.1 GHz to 6.8 GHz was designed. The DNGD circuit presented can be used in various telecommunication areas notably for correcting RF/numerical signal delays in the RF-microwave analogue-digital devices.     

Design,fabrication and characterization of miniature RF MEMS switched capacitor based phase shifter

This paper aims to present in detail the design, fabrication and the various characterization techniques adopted in realizing a novel miniature-size switched capacitor based phase shifter. The work strives to provide an all-round development of a DMTL (Distributed MEMS Transmission Line) based phase shifting unit yielding an overall phase shift of 15° at a frequency of 15 GHz. The RF MEMS (Radio Frequency Micro Electro Mechanical Systems) Switched Capacitor based phase shifter has highly miniaturized dimensions, and is capable of solving many limitations to which the conventional Switched Capacitors are mostly susceptible. This miniature RF MEMS switched capacitor actuates at a low actuation voltage of 12 V, exhibits a fundamental frequency of vibration as high as 1.468 MHz and a switching time of 1.4 µs which is an improvement over the other reported designs. Various characterization results seem to validate the simulations.     

移相器的原理及制作

移相器是用以调节交流电压相位的装置.着重论述了六边形移相器的原理、电路及制作.所设计制作的移相器能够在0°～360°.范围内达到任意角度的超前或滞后移相,并具有波形畸变系数小、无噪声、无振动、调节性能好等优点.实际应用证明了该设计制作的合理性和可行性.     

基于中低压器件实现的高压负电平位移电路

提出了一种新型高压负电平位移电路.该电路只采用中低压PM()S来实现高压电平位移,与传统的高压负电平位移电路相比,降低了工艺及器件难度.分析了该新型电平位移电路的电路结构与工作原理.采用1μm CMOS工艺,通过HSPICE进行电路仿真验证,证明提出的高压负电平位移电路正确可行.     

基于SP4T开关的4位MEMS开关线式移相器设计

设计了一款4位MEMS开关线式移相器,由SP4TMEMS开关和微带传输线构成,工作于X波段。单刀四掷(single pole 4throw,SP4T)开关用于切换两条不同电长度的信号通道,即参考相位通道和延迟相位通道。每个SP4T开关包含4个悬臂梁接触式RF MEMS串联开关。介绍了4位MEMS开关线式移相器的总体设计,并给出了其关键部件SP4T开关和相位延迟线的设计细节。采用ADS软件仿真分析了器件的电气性能。仿真分析得到:SP4T开关在中心频率10GHz处的回波损耗为-36dB,插入损耗约为0.18dB;移相器各相位的回波损耗均低于-15dB,插入损耗为-0.8～-0.4dB。这种射频MEMS移相器具有小型化、低功耗和高隔离度的优点。     

相控阵天线的设计与FDTD分析

基于工作频率在1.79 GHz的微带天线,首先研究了移相器的设计方法,然后利用两种不同方法实现的移相器,分别设计出了相控阵天线。通过FDTD进行建模和仿真实验,计算了相控阵天线在不同扫描角的远场辐射方向图,分析了实验误差,得出了结论,所设计的相控阵天线结构简约,主瓣尖锐,最大扫描角大于45°。     

应用于DBS移动接收中的5位数字移相器——低成本、Ku波段

提出了一种应用于DBS移动接收中的5位数字移相器的设计方案,并通过实验验证了其实际性能。该移相器采用加载线型和反射型移相原理,首先应用ADS软件进行设计仿真;仿真结果显示该移相器具有频带内高移相精度、低插入损耗和低VSWR等性能,符合设计要求。最后使用Agilent矢量网络分析仪对实物进行测试,进而验证了设计方案的正确性。     

用数控移相器实现对脉冲多普勒雷达的干扰

脉冲多普勒雷达是一种新型体制雷达,其发展基础源于动目标显示雷达。过去,对脉冲多普勒雷达进行干扰的器件是行波管,在其螺线极与地之间加锯齿波信号实现载频移频,加噪声信号实现噪声调相,这种方法存在诸多弊端。随着数字技术的快速发展,数控移相器具备小体积、高速度、低输入、易控制等优点,而这些特点正是行波管所欠缺的。故采用数控移相...     

一种移相器的损耗和匹配特性分析

移相器是电调天线的关键部件,通过对一种常用移相器的损耗和匹配特性进行详细分析,指出其可能出现的谐振损耗和失配,并提出了设计这类移相器应避免和该采取的措施。     

基于腔输入-输出过程的原子Bell态分析器和GHZ态分析器

如何能够在不破坏纠缠态且能将其辨认区分出来是量子信息处理过程中一个很重要的问题,方案首先利用相干光与腔-原子系统的输入-输出过程构造受控相移门,然后利用受控相移门和零差探测技术构造宇称分析器,最后利用宇称分析器和Hadamard等操作构造非破坏性的原子Bell态分析器和原子GHZ态分析器。方案的优势在于:（1）利用到相干光源和零差探测技术,比以往方案中的单光子源和单光子探测较易实现;（2）构造的原子Bell态分析器和原子GHZ态分析器是非破坏性的。方案用到的所有方法和技术在目前的实验上都是可以实现的。