基于2μm GaAs HBT工艺的E类功率放大器设计

本文采用Win公司2μm GaAs HBT工艺设计一种高效率射频E类功率放大器。设计中采用了电压偏置的E类功放结构,通过负载牵引(Load-Pull)技术对放大器的效率、增益和输出功率进行折衷和优化设计。仿真结果表明该放大器在5V电源电压下,工作频段700MHz～1100MHz内功率附加效率(PAE)大于50%,增益15dB,输出功率大于20dBm。芯片面积为1.375mm*0.79mm。     

高效率E类放大器

E类放大器是一种新型高效率功率放大器,理论效率接近100％,有很好的发展前景,本文介绍了E类放大器当前发展概况、电路结构、工作原理、技术特性;给出了理论分析、设计方法以及微波频段E类放大器出现的新问题,最后给出集中参数电路和微带电路的E类放大器实例。     

一种宽禁带器件的高效E类功率放大器设计

E类功率放大器是一种新型高效率放大器,属于开关模式功率放大器,其理论效率可以达到100%。可用于雷达、通信和电子对抗等领域的末级功率放大器,是系统高效率、高功率和小型化功率放大器的重要途径。通过分析其工作原理,设计了一款L波段高效E类功率放大器,输出功率大于10 W,实际漏极效率达到74.8%。     

高效率E类放大器(续)

(接上期第44页) 3 E类放大器设计与特性分析 1977年F.H.Raab[1,2]提出分析E类放大器的最佳工作条件的方法,其后也不断有分析、设计E类放大器的新方法.但这些方法也存在种种缺点[14,23],诸如未考虑最佳工作条件、优化算法耗时费力、算法的不收敛性以及对输出功率等电路参数不可控制等. 1994年,C.H.Li与Y.O.Yam[26]提出了简便易行的基于分析的电路参数设计方法以及一种新的分析方法,文献[40]又加以改进,并取得了理论值与实验值相吻合的结果,说明这种设计分析方法是合理的.这种方法的优点是在给定频率、输出功率、电源电压等参数后,用电路参数设计方法可设计出最佳工作条件下的放大器的电路元件值,并可计算此时的主要工作波形诸如输出电压、开关管(电路中的晶体管工作时处于开关工作状态,以下称为开关管)电压、电流,以及放大器效率、输入功率、输出功率、损耗功率等结果.     

高效率E类射频功率放大器

研究了E类RF放大器的电路结构、工作原理、存在问题以及解决的方法--差分和交叉耦合反馈结构,最后给出了E类放大器的实例.由于具有低成本、高集成度、多功用等优点,MOS工艺在射频功率放大方面有很大的发展潜力.在本文中,用0.6 u m CMOS工艺实现了E类放大器的设计.     

高效率开关F3/E类功率放大器

介绍了一种高效F3/E类功率放大器的设计方法,该放大器将F类功率放大器的谐波控制电路引入逆E类功率放大器的负载网络,以改善放大器性能。此电路结构提升了放大器的功率输出能力,降低了电路对功率放大器管器件漏极耐压特性的要求,增强了器件工作时的安全性。详细阐述了该放大器的设计过程,并给出了负载网络各器件的最佳设计取值方程。选用GaNHEMT器件研制了S频段F3/E类功率放大器测试电路。实测结果表明该放大器在驱动功率为27 dBm时,可获得40.3 dBm的输出功率,具有13.3 dB增益,工作效率高达78.1%,功率附加效率为75.2%。实测结果与仿真结果吻合,验证了设计方法的正确性。     

高效E类功率放大器的设计

E类功率放大器是一种新型高效率放大器。是实现通信对抗领域用高效率、高功率、小型化功率放大器的重要途径。分析了其工作原理和设计计算方法，并根据计算结果设计了一款短波500W高效E类功率放大器，实际效率接近90％，而且体积小、增益高。     

记忆多项式数字预失真线性化逆E类功放

采用记忆多项式模型的数字预失真器,用于线性化逆E类射频功率放大器,从而获得具有高线性和高效率的射频放大系统,使得开关型的逆E类功率放大器可以适用于具有非恒包络的调制信号的发射。文中设计了一个工作于S频段的具有10W饱和功率的逆E类功率放大器,以具有5MHz信号带宽的单载波WCDMA信号作为测试信号,使用记忆多项式的预失真器对其进行线性化。实验表明,该记忆多项式预失真器能够很好地抑制逆E类功放的动态非线性引起的带外寄生频谱,可以使逆E类功放同时工作于高线性和高效率状态。     

一种55 nm CMOS 5 GHz高效E类射频功率放大器

为了减小功率放大器的功率损耗、提高功率附加效率,基于TSMC 55 nm CMOS工艺,设计了一种工作频率为5 GHz的高效率E类射频功率放大器。采用包含驱动级的两级电路结构,提高了电路的功率增益。对负载回路进行优化设计,改善了漏极电压与电流波形交叠的问题,进而提升了效率,同时降低了漏极电压的峰值,缓解了晶体管的击穿压力。仿真结果表明,电源电压为2.5 V时,该放大器的输出功率为21.2 dBm,功率附加效率为53.1%。     

具有自动稳幅功能的软激励C类大功率射频振荡器

介绍了一种具有自动稳幅功能的软激励C类大功率射频振荡器。大功率射频振荡器已经广泛应用于电力电子、射频电源、低温等离子体、高频感应加热等领域。该大功率射频振荡器能够输出较高的输出电压和输出功率,并且通过对输出电压采样控制MOS管的静态工作点,稳定输出电压;另外,该设计电路起振时工作在AB类状态,稳定工作时在自动稳幅电路的作用下进入C类工作状态,实现了C类射频振荡器的软激励。最后通过仿真和实物电路测试了电路性能,并给出了振荡器输出电压、输出功率与MOS管工作状态关系的经验公式。     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.