A low-noise GaAs MESFET made with graded-channel doping profiles

We have demonstrated that devices fabricated from epitaxially grown material with a graded-channel doping profile are capable of improved microwave performance. For operation at 12 GHz, graded-channel doping profile devices have an associated gain that is always 1 dB higher at the minimum noise-figure point compared to ion-implanted Gaussian-channel doping profile devices. A noise figure of 1.60 dB with 11-dB associated gain has been obtained at 12 GHz for 0.5-µm × 300-µm gate devices. A tranconductance of 200 mS/mm for this device has been achieved.     

Distributed effect in GaAs MESFET

In order to obtain higher output power, the width of a single cell MESFET must be large. When it becomes too large the distributed effect along the width direction tends to limit the output power. In this paper, we found that the distributed effect is important when the gate width ≥ 150 μ and that the gain decreases with gate width. Also found is that spurious oscillations occur due to line resonances at much higher frequencies than can be accounted for by the instability factor in the discrete device model.     

多栅GaAs MESFET开关

论述多栅开关的结构和特点。开关设计中需要考虑的一个重要因素是提高开关功率处理能力的同时减小插损 ,多栅开关由于其特殊的结构 ,很好地解决了这一问题。采用多栅结构 ,设计的移动通讯用 DPDT开关在 DC-2 GHz:IL<0 .75 d B,ISO>1 3 d B,VSWR<1 .5 ,P- 1 >1 0 W。开关芯片面积小、成品率高、封装成本低 ,适宜批量生产 ,并已在手机上试装成功。     

多栅GaAs MESFET开关的结构设计

论述了多栅开关的结构和特点.针对多栅开关器件结构设计中的参数栅栅间距的选取作了分析,确定当栅栅间距等于源漏间距对栅数的平均值时,开关性能最优,并在实验中得到验证     

多栅GaAs MESFET开关的结构设计

论述了多栅开关的结构和特点.针对多栅开关器件结构设计中的参数栅栅间距的选取作了分析,确定当栅栅间距等于源漏间距对栅数的平均值时,开关性能最优,并在实验中得到验证.     

微波双栅GaAs MESFET

按照一种新的双栅器件设计理论,采用阶梯栅和两栅间嵌入虚接地点的结构,使GaAs双栅FET获得了优良的噪声和增益性能。二栅在管壳内通过电容射频接地,有助于稳定性的改善。器件最好水平为f_0:12GHz,N_F:2.42dB,G_(?):13.89dB。该器件设计合理,工艺经过优化,使器件具有较高的成品率及优品率。     

GaAs MESFET interface considerations

Various properties of GaAs MESFET's are discussed in terms of the basic physics of interfaces and deep levels. Fermi-level pinning is shown to lead to hole injection from a positively biased metal lying in direct contact with semi-insulating GaAs. This hole injection is partially responsible for low-frequency oscillations in GaAs MESFET's. Backgating and low-frequency oscillations are shown to be a direct consequence of the peculiar nature of the channel-substrate interface. This interface is discussed within the framework of a three-level model.     

GaAs MESFET灵敏度分析

本文叙述了灵敏度分析的重要意义。介绍了所用的MESFET模型与三个子程序DATA,MODEL,SPARAM及主程序SENSIT,并给出计算分析结果。结果表明,对MESFET芯片S参数影响最大的几个工艺变量、材料变量及基本物理参量,按灵敏度因子大小排列顺序为εγ,L_g,N_d,μ_o,A_s,A,L_(gs2),L_(gs3)。     

GaAs MESFET modeling and nonlinear CAD

Equivalent circuit modeling techniques are described for both small-signal and large-signal models of GaAs MESFETs. The use of large-signal model in an interactive program for amplifier analysis is shown. The computed load-pull results and IMD (intermodulation distortion) predictions are shown to be in good agreement with measured data at 10 GHz     

1WKu波段GaAs MESFET

采用新型通孔结构制作的微波功率GaAs FET,在12GHz,输出功率达1.2W,相应功率增益为6.6dB。在15GHz输出功率为1.1W,相应增益为5.5dB,漏极效率大于30％。     

GaAs MESFET非线性CAD模型综述

介绍了ＧａＡｓＭＥＳＦＥＴ应用在商业软件中的四种非线性ＣＡＤ模型、ＰＳＰＩＣＥ程序中的ＳＴＡＴＺ模型、ＥＥｓｏｆ微波电路模拟程序中的Ｃｕｒｔｉｃｅ对称和不对称模型以及ＱＵＡＳＩ程序中改进的ＳＴＡＴＺ模型。在给出多种模型ＤＣ方程和源漏电容公式的同时，对三种电路模拟程序的应用范围进行了分析。     

GaAs MESFET Small-Signal X-Band Amplifiers

This paper describes several techniques used to design and realize small-signal amplifiers at X band using Plessey 1-mu m gate-length GaAs MESFET's. Noise figures of 3 dB or better at 8 GHz with associated gains of 5.5 dB have been produced. The mounting of GaAs MESFET's on 25-mil-thick alumina substrates and their S-parameter characterization is described. Owing to some uncertainties in these measurements, four parallel approaches were used to realize amplifiers. The "designed," "semidesigned," "semituned," and "tuned" methods are described and results are presented for each case. A semidesigned single-stage amplifier has a gain of 8 /spl plusmn/ 0.6 dB from 8.5 to 9.5 GHz and a minimum noise figure of 4.4 dB. A semituned amplifier can be tuned from 8 to 10 GHz with VSWR's less than 2:1 over any 600-MHz bandwidth in that range.     

Complementary GaAs MESFET logic gates

Operation of the first complementary GaAs MESFET (CMES) logic gates is reported. Direct-coupled inverters utilizing p- and n-channel ion-implanted MESFET's demonstrate good transfer characteristics with less than 5-µW power dissipation per gate. Propagation delays as small as 54 ps are attained in 13-stage ring oscillators at room temperature with speed-power products as small as 6 fJ.     

GaAs MESFET differential pass-transistor logic

Two GaAs MESFET implementations of differential pass-transistor logic (DPTL) are presented. The DPTL logic technique combines the area efficiencies and high operation speeds of ratioless pass-transistor circuits with the additional features of noise immunity and low power dissipation. Circuit structures are presented for both depletion (D)-mode and enhancement/depletion (E/D)-mode MESFET technologies, and are compared with buffered FET logic (BFL) and direct-coupled FET logic (DCFL), respectively. Experimental results are provided to verify the functionality and the performance features of both DPTL forms     

偏置相关GaAs MESFET建模分析

通过对利用多组偏置条件下的Ｓ参数获得精确ＡａＡｓＭＥＳＰＥＴ器件非线性模型方法的讨论，提出了新的沟道电流和栅电容模型，并提取了ＤＣ和电容模型参数。实验结果表明该模型模拟值和测量值吻合很好。     

High-Speed Enhancement-Mode GaAs MESFET Logic

High-speed enhancement-mode GaAs MESFET Iogic circuits have been fabricated by electron beam lithography. A 15-stage ring oscillator composed of 0.8-mu m gatelength and 40-mu m gatewidth inverters has given a minimum propagation delay time of 77 ps at a power dissipation of 977 mu W. A minimum power-delay product of 1.6 fJ has been obtained with a 20-mu m gatewidth circuit at a propagation delay time of 200 ps. Liquid nitrogen temperature operation has also been performed, and a speed almost twice higher than that at room temperature has been obtained. The minimum propagation delay time was 51 ps, and the associated power dissipation was 1.9 mW.     

GaAsMESFET和DHEMT的中子辐射效应研究

本文介绍了ＧａＡｓＭＥＳＦＥＴ和ＨＥＭＴ的中子辐射效应。依据中子辐射损伤机理，分析了器件参数与中子辐射剂量Φ的依从关系，其中，器件参数包括物理参数Ｎ＿Ｄ、Ｎ＿ｓ、Ｖ＿ｓ，μ和电参数Ｉ＿ＤＳ、ｇ＿ｍ、Ｖ＿ｐ、Ｇ等。     

10GHz 1W GaAs MESFET

<正> 一、引言自从1966年C. A. Mead提出肖特基场效应晶体管以来,GaAsMESFET作为一种微波器件受到广泛重视。短短十几年来已取得突飞猛进的发展。在4～20GHz的频率范围内,GaAs功率MESFET已被公认为是一种最好的微波功率器件。它具有结构简单、体积小、重量轻、功率大、效率高、线性好、频带宽等优点。在相控阵雷达、卫星和地面通信、电子对抗及卫星直播电视中得到广泛的运用,有着广阔的发展前景。     

A high-speed GaAs MESFET optical controller

Optical interconnects are being considered for control signal distribution in phased array antennas. A packaged hybrid GaAs optical controller with a 1:16 demultiplexed output that is suitable for this application is described. The controller, which was fabricated using enhancement/depletion mode MESFET technology, operates at demultiplexer-limited input data rates up to 305 Mb/s and requires less than 200 μW optical input power     

GaAs MESFET开关模型

本文提出了一种MESFET开关的模型———附加栅控开关模型 ,适用于MMIC电路的设计 ,其具有很好的宽带微波特性。开关单片的设计值与模型模拟值吻合较好。