集成光学声光光开关的研究

在集成光学声光可调谐滤波器的基础上，研制成一种偏振无关的集成光学波导型声光光开关，由于采用声光作用实现开关功能，使得开关速度可以达到微秒量级。介绍了这种集成光学波导型声光光开关的工作原理及其基本结构，并对它的插入损耗、隔离度、开关速度这三项光开关的重要性能指标进行了具体的理论分析与计算，然后对制作成的集成光学波导型声光光开关的器件样品进行了性能测试，在室内温度为20℃，入射波长为1．523μm时，测得插入损耗为4．8dB，隔离度为22．0dB。对实验与理论的误差进行了具体分析，并提出了进一步提高其性能指标的相关途径。     

一种L～E波段的混合型射频MEMS单刀双掷开关设计

针对传统RF MEMS单刀双掷(SPDT)开关应用存在频段低、插入损耗高、隔离度低等问题,设计了一种混合型SPDT开关,通过在一条通路上设置接触式开关和电容式开关,实现了在L～E频段下的低插入损耗和高隔离度。通过设计蛇形上电极结构,降低了上电极的弹性系数,进而降低开关上电极下拉所需的驱动电压。采用HFSS仿真软件对混合型SPDT开关的射频性能参数进行了优化,并利用COMSOL对开关的蛇形上电极进行应力-位移分析。仿真结果表明,在DC～90 GHz的频段下,SPDT开关的插入损耗小于1.5 dB@90 GHz,隔离度大于52 dB@67 GHz、29 dB@90 GHz。此开关适用于无线通信系统、雷达系统和仪器测量系统等对工作频段要求高的领域内。     

高隔离度宽频段组合式RF-MEMS开关的设计

接触式与电容耦合式两类RF MEMS开关各自在一定的频段内,都具有较高的隔离度,但仍然很难满足微波控制系统中对高隔离度的要求.为了获得全波段高隔离度RF MEMS开关,单元开关很难达到要求,在此目标要求下,提出了组合式RF MEMS开关的设计,分别利用HFSS软件对各单元进行结构参数优化,再将两者集成在一起,得到的组合式RF MEMS开关,这种组合式开关在0～20 GHz时隔离度都高于-60 dB,在(≤5 GHz),隔离度高于-70 dB,这是一般单元开关及其他半导体固态开关所无法企及的,而且,在DC～20 GHz范围内,开关的插入损耗小于-0.20 dB,而且并没因隔离度的提高,牺牲了插入损耗.     

反射型GaAs光控微波开关

对反射型ＧａＡｓ光控微波开关的结构、实验系统和特性参量进行了研究。实验测出该微波开关的插入损耗低于１ｄＢ，隔离度达到３０ｄＢ。用５０ｎｓ光脉冲照射开关，其开关速度小于１０ｎｓ。     

双膜桥微波MEMS开关

介绍了一种双膜桥微波MEMS开关，给出了开关的设计与优化方法，建立了开关的仿真模型，使用硅表面微机械工艺制造了双膜桥开关样品，其主要结构为硅衬底上制作CPW金属传输线电极和介质层，然后制作具有微电感结构的金属膜桥，提高了开关隔离度。利用HFSS软件仿真的结果表明，该开关在微波低频段(3～6GHz)有着很好的隔离性能。研制的开关样品在片测试的电性能指标为：插损小于0．3dB，隔离度大于40dB，驱动电压小于24V。     

高频模拟开关设计

通过带通视频模拟开关设计,对高频模拟开关的高频隔离度、插入损耗和开关速度等三个主要指标进行了分析;阐述了高频模拟开关的设计思路和方法。     

宽带单刀多掷PIN开关的设计

介绍了微波PIN开关的电磁结构模型的建立及计算机仿真，讨论了宽带单刀多掷开关的设计要点。采用该方法成功设计了1—18GHz吸收式单刀五掷开关，其插损≤3．5dB．驻波≤2．2，隔离度≥60dB。     

RF MEMS单刀四掷矩阵开关的研究

介绍了一个RF MEMS单刀四掷矩阵开关的设计，用四个串联式、电阻接触型、悬臂梁RF MEMS开关制作在微带电路板上完成。在频带1～5GHz内，单刀四掷矩阵开关的插入损耗〈0．8dB，开关隔离度〉38dB，驻波系数〈1．2。悬臂梁开关的激励电压为直流电压35～45V。     

改进K型单刀四掷射频MEMS开关

针对射频器件小型化以及5G通信发展的需求，设计了一款射频微机电系统（RF-MEMS）单刀四掷开关。该开关由一个改进型K型功分器和六个单刀单掷开关级联构成，并基于硅基MEMS工艺进行制造。其中，改进型K型功分器由多个Y型功分器串并联构成。改进的开关各端口具有插入损耗小和隔离度高的特点。最终流片的测试结果显示：该单刀四掷MEMS开关的插入损耗优于2.8 dB，隔离度优于29 dB。     

混合集成高隔离多路开关的研制

本文阐述了混合集成高隔离多路开关的设计与研制，高隔离多路开关具有隔离度高，插损小、四路之间影响小、集成度高、体积小、使用方便等特点。     

Monolithic array of optoelectronic broad-band switches

The response of monolithic arrays of GaAs photoconductors to optical intensity modulation signals and their feasibility of operating as crosspoint arrays in integrated broadband switch matrices are investigated. It is found that individual photoconductors can switch signals at frequencies of up to 1.3 GHz with isolation better than 70 dB and switching time less than 10 ns. In a 2/spl times/2 monolithic array, 65-dB switch isolation and 80-dB crosstalk isolation between channels are achieved in the frequency range 0-130 MHz. The responsivity is essentially uniform within this frequency range and has a value of 0.84 A/W at 820 nm. At higher frequencies electromagnetic coupling between output lines limits the performance with the layout used. This monolithic array thus demonstrates compact broadband matrix switching of signals in the frequency range up to 100 MHz using the optoelectronic switching principle.     

开关电源的隔离技术

对开关电源电路的各种隔离技术进行了详尽的分析讨论，提出了抑制干扰而采取的电气隔离的技术措施，从而保证开关电源的正常工作。     

Fast photoconductive optoelectronic broadband switch with low control voltage

Optoelectronic switching with a gallium arsenide field-effect transistor used as a photoconductive detector is demonstrated. On-state to off-state isolation ratios of 65 dB from 500 kHz to 1.3 GHz, and switching times less than 10 ns, are observed. Gating voltage is of the order of 3?10 V.     

On the synergy between electrical and photonic switching

This article focuses on the values of electrical switching vs. photonic switching in the context of telecom transport networks. In particular, we show that the requirement of providing agility at the optical layer in the face of traffic forecast uncertainties is served better through photonic switching. On the other hand, some of the network-level functions, such as fast protection, subwavelength aggregation, and flexible client connectivity, require electrical switching. We further argue that additional values are achieved with hybrid photonic and electrical switching, which do not exist when either of these options is used in isolation.     

High-Speed Microwave Switching of Semiconductors--II

A relationship between low-power isolation and small-signal, low-frequency diode resistance is reported. A study of ambient heating indicates that with increasing temperature the diode characteristics tend to approach the line characteristic of the above relationship. Observed switching speeds of 1.5 to 3.0 mµs are reported. A theory is presented which agrees with the switching time data and predicts microwave switching times as low as 0.2 to 0.3 mµs. High speed switching is discussed with reference to significant parameters, e.g., hole storage, internal heating, and pulse reverse diode characteristics.     

Low-voltage high-isolation DC-to-RF MEMS switch based on an S-shaped film actuator

This paper presents a new electrostatically actuated microelectromechanical series switch for switching dc to radio frequency (RF) signals. The device is based on a flexible S-shaped film moving between a top and a bottom electrode in touch-mode actuation. This concept, in contrast to most other microelectrochemical systems (MEMS) switches, allows a design with a low actuation voltage independent of the off-state gap height. This makes larger nominal switching contact areas for lower insertion loss possible, by obtaining high isolation in the off-state. The actuation voltages of the first prototype switches are 12 V to open, and 15.8 V to close the metal contact. The RF isolation with a gap distance of 14.2 /spl mu/m is better than -45 dB up to 2 GHz and -30 dB at 15 GHz despite a large nominal switching contact area of 3500 /spl mu/m/sup 2/.     

基于液晶光子晶体波导耦合的光开关特性分析

提出了一种基于液晶光子晶体波导耦合的光开关结构。采用平面波展开法(PWE)分析了光开关耦合区域的色散关系,分析表明可以通过设计适当的耦合区域长度使该结构对不同波长的光实现2×2光开关的功能。以工作波长1550nm和1565nm为例,用时域有限差分法(FDTD)对光开关的性能进行了仿真分析,结果表明开关具有低的插入损耗和高的通道隔离度,开光响应时间在毫秒量级。     

Characteristics of metal/tunnel-oxide/n/p+ silicon switching devices—II: Two-dimensional effects in oxide-isolated structures

Effects of oxide isolation on the two-terminal D.C. characteristics of metal/tunnel-oxide/n/p⁺ silicon switching devices have been studied.Recent experimental results have shown that the switching characteristics are strongly dependent on area, and area-to-perimeter ratio of the device. To carry out a systematic investigation of this phenomenon, the devices in this study were isolated using V-grooves of various areas. For a given tunnel-oxide thickness and area, it was found that the magnitude of the switching voltage and holding current of the device increased with isolation area, whereas the switching current remained essentially constant. Furthermore, it is shown that the switching current is almost completely determined by the characteristics of the tunnel-oxide; in particular, the minority carrier concentration at the SiSiO₂ interface. Physical arguments are presented which adequately explain the observed trends. It is also experimentally shown that both switching current and holding current decrease as the tunnel-oxide thickness is increased.A simple two-dimensional model for the oxide-isolated MISS device is derived which effectively explains the above area-related phenomena. In agreement with experimental results, the model predicts that for a given tunnel-oxide thickness and area, an increase in switching voltage magnitude and holding current will result as the isolated p⁺-n junction area is increased. Calculations based on this model are shown to be in good agreement with experimental data.     

A three Josephson junction direct coupled isolation device

A new type of current switching logic device using three Josephson junctions is described. This device allows the simultaneous optimization of both the gain and the operating margin. It shows an enhanced threshold curve compared with that of the Direct Coupled Logic (DCL) isolation device and the Josephson Atto-Weber Switch (JAWS). Design optimization and simulation results are presented. The device shows an almost square current transfer curve indicating good input and output isolation. The dependence of delay on fan-out is also discussed. For a fan-in of 1 and a fan-out of 3, the switching delay is 38 ps with a power dissipation of 3.6 µW.     

Novel Low-Overhead Operand Isolation Techniques for Low-Power Datapath Synthesis

Power consumption in datapath modules due to redundant switching is an important design concern for high-performance applications. Operand isolation schemes that reduce this redundant switching incur considerable overhead in terms of delay, power, and area. This paper presents novel operand isolation techniques based on supply gating that reduce overheads associated with isolating circuitry. The proposed schemes also target leakage minimization and additional operand isolation at the internal logic of datapath to further reduce power consumption. We integrate the proposed techniques and power/delay models to develop a synthesis flow for low-power datapath synthesis. Simulation results show that the proposed operand isolation techniques achieve at least 40% reduction in power consumption compared to original circuit with minimal area overhead (5%) and delay penalty (0.15%)