自旋波器件及其在微波技术中的应用

本文述叙自旋波的特性和利用这些特性所能做成的新型铁氧体器件,并说明这些器件在微波技术中的一些应用。     

最近的微波铁氧体技术

引言关于微波铁氧体器件技术,以前曾在本杂志上作过几次介绍。但是,最近随着材料的改进和器件技术的研究,特别是材料性能的更加精细的测量,感到在此领城有了更进一步的发展。因此,这次特地以1971年8月的欧洲微波会议,1972年3月的国际微波铁氧体技术研究班、还有1972年4月的国际应用磁学会议上发表的资料为中心,叙述最近     

GaN高电子迁移率晶体管的研究进展

GaN高电子迁移率晶体管(HEMT)是GaN微波功率器件的主要形式,是第3代半导体技术领域发展和竞争的焦点.针对GaN HEMT的目标特性和电流崩塌现象,从材料结构设计和器件设计两方面概括了十几年来GaN HEMT器件性能优化的研究方法,并给出了国内外GaN HEMT器件微波功率特性目前的研究进展水平.     

InP基PIN开关二极管结构设计与制备

开关二极管是微波控制电路中的一种应用最普遍的控制器件,它可以实现近似短路和开路的功能.Ⅰ层厚度对PIN二极管的器件特性具有重要的影响.利用Silvaco TCAD软件对InP基PIN开关二极管器件结构进行建模仿真,分析不同1区厚度对二极管的电流电压特性的影响,得出最优值.利用化合物半导体材料外延与器件工艺平台,制备出InP基PIN开关二极管器件,直流特性测试结果表明,PIN开关二极管的开启电压为0.525 V,反向击穿电压大于12 V.为进一步实现毫米波开关电路奠定了基础.     

铁磁谐振变压器的等效电路

本文指出了变压器Ｔ型等效电路在分析铁磁谐振变压器时的局限性。提出了π型等效电路模型。描述了从给定的电磁器件的磁路获取等效电路的方法。在π型的等效电路中，电子元件的特性与给定电磁器件的特性具有一一对应的关系。仿真试验证明了此方法的有效性。     

近年来微波铁氧体回顾与展望

最近十年,微波铁氧体材料与器件的发展动向愈发趋千集中。微波器件的设计者们已将注意力转向限制条件更加严格或不断改良的材料,所设计的器件也仅限于较少的几类。此间,对于材料和器件的了解进一步加深,并且建立了精确度极高的铁氧体环行器和移相器的理论模型。随着军用相阵雷达系统与星载微波通讯系统的投入使用,铁氧体器件的总产量也在不断增长。     

微波铁氧体器件现状及新一代集成化微波铁氧体器件展望

阐述了微波铁氧体器件发展现状,指出了微波铁氧体器件当前应该发展的技术方向和亟需突破的关键技术,强调微波铁氧体器件小型化和便于IC集成要求迫在眉睫。为实现微波铁氧体器件的小型化,从微波铁氧体器件基本原理入手,论述了圆极化概念在微波铁氧体器件功能实现和性能优化方面的重要作用,提出了采用绝缘多导体磁性结构实现可满足小型化和便于集成化要求的新一代微波铁氧体器件的基本思路。绝缘多导体磁性器件结构可实现多个TEM波模式的混合传输,利用此构造关于磁化偏置方向的正负圆极化波,从而产生显著的非互易传输和电控特性。TEM模式没有低频截止问题,器件尺寸可大体不受波长比拟规则的限制,通过目前日趋成熟的磁性集成化工艺,可实现小型化和便于IC集成化的新一代微波铁氧体器件。     

铁磁谐振变压器的等效电路

本文指出变压器Ｔ型等效电路在分析铁磁谐振变压器时的局限性。提出了π型等效电路模型。描述了从给定的电磁器件的磁路获取等效电路的方法，在π型的等效电路中，电子元件的特性与给定电磁器件的特性具有一一对应的关系。仿真试验证明了此方法的有效性。     

资料索引

一、微波材料及器件 1.钙钒系铁磁石榴石(用于微波电路元件,也含有担和忆的氧化物) J .P.49一027228 2.钙钒系铁磁石榴石(用于微波电路元件,也含有秘、担和锗的氧化物) J .P.49一027229 3.TIO:和恒定磁场对TIOZ一FeZ仇一CaO一VZO。系铁氧体介电参数的影响 HeoPr.MaTeP,ToM 12,BHn.5,eTP.910,1976·4.六角晶铁氧体(用于共振隔离器) U .5.P.3770639 5.超高频磁性材料(有镍一锌一钻铁氧体和钡一银铁氧体,分别为尖晶石晶体和平面型晶体 结构) J .P.49一0304356.六角晶铁氧体的液相外延(适合于表面波器体) Materials reseach bullt…     

微波铁氧体器件的新应用

本文根据我们具体的工作实践,就我们研制的一些特种微波铁氧体器件.尤其是电控微波铁氧体器件在整机中的新应用进行了报导,它们对提高整机的性能起了很大的作用。     

Magnetoelectric interactions in ferromagnetic-piezoelectric layered structures: Phenomena and devices

Layered magnetostrictive-piezoelectric structures are multifunctional due to their dual-responsiveness to mechanical and electromagnetic forces. Here, we discuss studies of magnetoelectric (ME) interactions in ferrite-lead zirconate titanate (PZT) and terfenol-PZT material couples. Key findings include: (1) the observation of a giant low-frequency ME effect in the layered systems; (2) data analysis based on our model for low frequency ME effects; (3) observation and theory of enhanced ME coupling at the electromechanical resonance (EMR); and (4) theory and measurements of microwave ME effects, at the ferromagnetic resonance of ferrites. The layered structures are potential candidates for sensors, gyrators and microwave devices. Low frequency sensors are feasible with excellent sensitivity to minute magnetic field variations. One could also realize composite based ferromagnetic resonance devices, such as resonators, filters and phase shifters with electric field tunability for use at 1–70 GHz.     

磁化铁氧体电磁参数的测试

为研究微波铁氧体器件,需要获知磁化后铁氧体的电磁性能参数。以具有高磁晶各向异性场的六角晶型铁氧体为材料,在22-40GHz的频率范围内对磁化后材料的共极化和交叉极化透射系数进行了测试,然后采用数值仿真透射系数与实验测试结果拟合的方法,得到了磁化六角晶型铁氧体的各向异性场H0为1095kA／m,共振线宽AH为7．5kA／m,饱和磁化强度Ms为160kA／m和在Ka频段时的介电常数ε约为22．1。结果表明六角晶系铁氧体具有高磁晶各向异性场,借助这些已获知的电磁参数,就可以使用此种材料进行微波铁氧体器件的研究与设计。     

GaAs FETs [microwave devices]

The field effect transistor (FET) at microwave frequencies using GaAs has been a cornerstone of research in solid state microwave devices for the past 30 years. It is an established item in the microwave systems of today in such applications as low noise amplifiers, mixers, oscillators, power amplifiers, switches and multipliers. Indeed, many microwave systems would not be possible at their present day performance levels if it were not for the GaAs FET     

Single nanowire assembled by liquid dielectrophoresis for on-chip technologies

ABSTRACT

Study on dynamic tensile properties and atomic chain fabrication of single nanowire, for understanding its dynamic tensile properties and unique physical properties of atomic chain to fabricate atom scale devices, is one of frontier research issues in nano-scale science. However, how to assemble single nanowire on a tensible micro-structure becomes one of the most difficult problems, which severely restricts the development of this research field. In this paper, after the ultrahigh tensible microelectrode chip is fabricated by micro-electromechanical systems technology, hexamethyldisilazane is utilized to improve hydrophobicity of the chip, and then a micro-droplet dielectrophoresis experimental platform and technology is developed to assemble single nanowire on the sensible microelectrode. Experimental results show that accurate and efficient assembly of single Cu nanowire is realized, which contributes greatly to the further research of dynamic tensile properties and atomic chain fabrication. And for guiding the assembly experiments, finite element technology is also utilized to analyze the local micro electro-field around the microelctrodes during dieletrophoresis experiments.     

Charting the microwaves waters. A short overview in table form forquick and easy referencing

The author presents tables of microwave frequencies, solid state devices and their applications, linear beam tubes (O-type), crossed field tubes (M-type), and applications of microwave electron tube devices     

Agile microwave devices

After years of material optimization and laboratory demonstrations of devices, the application of ferroelectrics in microwave technology is gaining momentum. At present, ferroelectric films are used in passive and agile microwave devices and systems including: · parallel-plate and coplanar-plate varactors · tunable resonators, filters, and matching networks · phase shifters and delay lines · ferroelectric-based frequency converters and harmonic generators · voltage-controlled oscillators (VCOs) and amplifiers using ferroelectric varactors · steerable beam antennas and phased arrays · tunable, frequency selective, and impedance surfaces · tunable thin-film bulk acoustic wave resonators (TFBARs) and filters · high-density decoupling capacitors and field dielectrics in CMOS devices. The current status of agile microwave technology is partly summarized in a book chapter [1] and a book [2]. The latter also gives a detailed review of applications of ferroelectrics in microwave technology and a forecast of possible future developments in the field. Several companies have started commercial development and marketing of ferroelectric varactors and devices based on them [3]-[6]. This article highlights the advantages of ferroelectric varactors and gives a few examples of devices and system-level commercialization strategies.     

Complementary split rings resonators (CSRRs): Towards the miniaturization of microwave device design

In this paper, it is demonstrated that complementary split rings resonators (CSRRs), a new type of planar resonators recently introduced by some of the authors, are key elements for the miniaturization of microwave devices implemented in planar technology, such as filters and diplexers. These devices essentially consist on a host transmission medium (microstrip line) to which the CSRRs are electrically coupled, and additional microstructure in order to achieve the required device performance. From the analysis and numerical simulations of the equivalent circuit model of the basic device cell, as well as electromagnetic simulations of actual structures, it is confirmed that CSRRs are useful resonators for the synthesis of planar microwave filters where dimensions, out-of-band performance and bandwidth can be simultaneously optimized. The simultaneous fulfillment of these aspects is a relevant advantage of the proposed structures. The possibility to implement band pass filters with wide bandwidth and high performance, the small electrical size of CSRRs, as well as their potential applications in other microwave devices, make these particles of actual interest in microwave engineering.     

Comprehensive modeling of optoelectronic nanostructures

This paper gives an overview of physics-based modeling of optoelectronic nanostructures, driven by diverse applications such as photovoltaics, solid-state lighting, communications and sensing. Despite this broad field of applications, some common challenges can be identified: accurate modeling of light-matter interaction, semi-coherent carrier transport in the presence of strong recombination, calculation of material properties and electromagnetic characteristics. In this contribution, the general purpose simulation framework tdkp/AQUA/LUMI is presented, with the focus on non-planar nanowire devices.     

Moving forward in retrodirective antenna arrays

Antenna arrays are individual radiating elements combined so that they function and perform like a single large antenna. Besides high radiating beam directionality, antenna arrays offer the capability to scan the main beam and control sidelobe radiation electronically. Retrodirective antenna arrays, as the name suggests, have a special feature. When receiving a signal from an unspecified direction, the array can automatically transmit a signal response to that same direction without any previous knowledge of the source direction. This function is performed automatically without the use of phase-shifters or digital circuitry. Compared to other array antennas that rely on digital signal processing (DSP) for beam direction control, this approach is much simpler and potentially faster because digital calculation is not needed. The automatic beam control nature of retrodirective arrays is well suited for RFID (radio frequency identification) and microwave tracking beacon applications. The article discusses the basic functionality as well as the ongoing research efforts and developments in retrodirective array architectures. Self-phasing attributes of different arrays are presented, as well as their applicability in practical communication systems.     

Composite right/left-handed transmission line metamaterials

Metamaterials are artificial structures that can be designed to exhibit specific electromagnetic properties not commonly found in nature. Recently, metamaterials with simultaneously negative permittivity (/spl epsiv/) and permeability (/spl mu/), more commonly referred to as left-handed (LH) materials, have received substantial attention in the scientific and engineering communities. The unique properties of LHMs have allowed novel applications, concepts, and devices to be developed. In this article, the fundamental electromagnetic properties of LHMs and the physical realization of these materials are reviewed based on a general transmission line (TL) approach. The general TL approach provides insight into the physical phenomena of LHMs and provides an efficient design tool for LH applications. LHMs are considered to be a more general model of composite right/left hand (CRLH) structures, which also include right-handed (RH) effects that occur naturally in practical LHMs. Characterization, design, and implementation of one-dimensional and two-dimensional CRLH TLs are examined. In addition, microwave devices based on CRLH TLs and their applications are presented.