0.2～30GHz GaAs FET开关模型的提取与验证

在GaAs单片微波集成电路(MMIC)设计中,准确的器件模型对于提高电路设计成功率和缩短电路研发周期起着重要作用。首先采用标准的GaAs MMIC工艺制造出不同栅指数和单位栅宽的开关PHEMT器件,然后对加工的开关电路在"开"态(Vgs=0 V)和"关"态(Vgs=-5 V)进行宽频率范围内的测量,基于测量结果建立起一个参数化的GaAs PHEMT开关等效电路模型,最后通过单刀单掷(SPST)开关来验证参数化模型。应用该参数化模型设计的电路实测与仿真结果基本吻合,证明参数化的GaAs PHEMT模型是可用的。该模型可用于30 GHz以下GaAs PHEMT工艺开关MMIC电路仿真设计。     

Extraction techniques for FET switch modeling

A new simple method for extracting equivalent circuit parameters for series and shunt GaAs FET switches is presented. The circuit elements are extracted from one set of S-parameter measurements for each switch state, and scale linearly with gate width. Extracted Equivalent Circuit Parameters (ECP's) are insensitive to frequency across the measured bandwidth. Good agreement has been obtained between simulated and model results for a 0.5 μm gate length series and shunt GaAs FET switches of varying gate widths, across the 0.45-26.5 GHz band     

S波段超宽带固态功率放大器的研制

本文结合一款新研制的S波段超宽带固态功率放大器,介绍了超宽带固态功率放大器的设计理论和方法,根据砷化镓场效应晶体管的小信号S参数和I-V曲线,用微波仿真软件对功率管的输入、输出阻抗匹配电路及其偏置电路进行优化仿真设计.通过制作并测试此放大器,验证了该设计方法的可行性.最后,给出了测试数据,它在2GHz～4GHz的频带范围内,输入功率为40mW时,输出功率大于20W,带内功率起伏小于1.5dB.     

Intrinsic Response Time of Normally Off MESFET's of GaAs, Si, and InP

A response time of normally off MESFET's for high-speed Iogic circuits made of GaAs, Si, and InP was calculated using a two-dimensional numerical analysis. The results indicate that GaAs is the best material among them. The step response of the InP FET is not as fast as expected from v/E characteristics due to low electric field in the channel for low-power logic operation of a normally off FET.     

X波段砷化镓场效应振荡管

X波段GaAs场效应振荡管是一种专门用于各种微波固体振荡电路的新型器件,尤其对X波段GaAsFET电压控制振荡器(VCO)和介质谐振器振荡器(DRO)更为适合。 本文在对有关资料分析的基础上,提出了设计这一器件的基本原则;概述了器件的基本结构;介绍了器件的参数研究结果和电路应用情况。用该器件制作的X波段FET VCO,得到了800MHz以上的电调范围,在整个电调范围内,输出功率为30～50mW,功率起伏小于1.5dB。     

砷化镓0.25μm PHEMT开关模型研究

借助于传统的FET等效电路模型,给出了0.25μm GaAs PHEMT的开关模型,并在ICCAP和ADS软件中,完成等效电路参数的提取与优化。通过对单刀单掷(SPST)开关的仿真和测试,表明,在0.1～20 GHz的频域内,其"开"态插入损耗误差、端口1和端口2的电压驻波比误差分别小于0.3 dB、0.24和0.19;其"关"态隔离度误差、端口1和端口2的电压驻波比误差分别小于1.9 dB、0.12和0.08。文中得到的PHEMT开关模型将有助于控制类单片集成电路的研究与开发。     

砷化镓双栅场效应管及其在微波电路中的应用

本文简述砷化镓双栅场效应管的基本特性及其在放大器、倍频器.混频器、振荡器、移相器和开关等微波电路中的应用.     

三值GaAs逻辑级电路的研究

本文首先讨论了ＧａＡｓＦＥＴ对三值信号的处理过程,对二值ＧａＡｓ电路的输出级等效电路与基于已提出的电路结构的多值ＧａＡｓ电路的输出级的等效电路进行了分析,并分析了该多值ＧａＡｓ电路结构的缺陷及其产生缺陷根源。     

带GaAs TTL电平驱动器的SPDT开关的模拟和性能

介绍了一种带ＧａＡｓＴＴＬ电平驱动器及单刀双掷（ＳＰＤＴ）开关的设计、模拟和测试结果。驱动器的设计采用了开关输入稳压负载,建立了所用器件的大信号模型,对电路进行了模拟分析和优化,模拟和测试结果吻合较好,开关时间达到５ｎｓ,插入损耗小于１．０ｄＢ,隔离度大于６０ｄＢ。     

GaAs MMIC射频开关设计与研制

介绍了ＧａＡｓＭＭＩＣＲＦ开关的设计方法,在这种方法中,把ＭＥＳＦＥＴ当作一个两端口网络处理,直接提取开与关两种状态下网络（ＭＥＳＦＥＴ）的Ｓ参数,应用Ｓ参数进行开关电路的ＣＡＤ。这种设计方法更准确,更简单,容易实现。文中还给出了ＧａＡｓＭＭＩＣＲＦ开关的研制结果。     

First-order, switched-capacitor, low-pass filter implemented with GaAs insulated-gate FET switches

The application of the GaAs insulated-gate FET in switched-capacitor circuits is demonstrated. This is achieved by constructing a first-order, switched-capacitor, low-pass filter from monolithic GaAs IGFET switches and discrete capacitors. Hysteresis in the FET characteristic is shown to be unimportant. FET switching is shown to be independent of the absolute level of the switching signal.<>     

The prospects for ultrahigh-speed VLSI GaAs digital logic

Recent advances in the state of GaAs integrated circuit fabrication technology have made possible the demonstration of ultrahigh performance (tau_{d} sim 100ps) GaAs digital IC's with up to 64 gate MSI circuit complexities and with gate areas and power dissipations sufficiently low to make VLSI circuits achievable. It is the purpose of this paper to evaluate, based on the current state of GaAs IC technology and the fundamental device physics involved, the prospects of achieving an ultrahigh-speed VLSI GaAs IC technology. The paper includes a performance comparison analysis of Si and GaAs FET's and switching circuits which indicates that, for equivalent speed-power product operation, GaAs IC's should be about six times faster than Si IC's. The state of the art in GaAs IC fabrication and logic circuit approaches is reviewed, with particular emphasis on those approaches which are LSI/VLSI compatible in power and density. The experimental performance results are compared for the leading GaAs logic circuit approaches, both for simple ring oscillators and for more complex sequential logic circuits (which have demonstrated equivalent gate delays as low astau_{d} = 110ps).     

Planar Models of Reconfigurable MEMS Circuits

This paper presents a general procedure for the electromagnetic modeling of arbitrarily shaped reconfigurable planar circuits using RF microelectromechanical systems switches. In this model, the reconfigurable structure is represented by a linear time-invariant planar multiport, which is connected through internal ports to as many variable lumped-element circuits as the switches. Unlike conventional equivalent circuits, in this technique, the lumped elements represent only a small portion of the switch, and their values are not affected by the proximity of the switch to line discontinuities or to other switches. For this reason, the same values can be reused, with no substantial constraint, in the modeling of very different reconfigurable structures. For any type of switch, the lumped elements are deduced from the experimental or simulated frequency response of a simple prototype. The (arbitrarily shaped) environment of the switches is taken into account in the planar multiport, which is modeled by using very efficient 2-D electromagnetic simulators. Therefore, a lot of different geometries can be easily experimented and the corresponding frequency responses can be readily calculated for any set of the switch states     

Dual-gate GaAs FET switches

A set of multi-pole, multi-throw switch devices consisting of dual-gate GaAs FET's is described. Included are single-pole, single-throw (SPST), double-pole, double-throw (DPDT), and single-pole four-throw (SP4T) switches. Device fabrication and measurement techniques are discussed. The device models for these switches were derived based on an equivalent circuit of a duff-gate FET. The devices were found to have substantial gain in X-band and low Ku-band.     

微波单片有源滤波器负阻电路的实现方法

论述了用于微波单片有源滤波器负阻电路的实现方法，给出了三种由单管ＦＥＴ构成的负阻电路，以及用ＭＭＩＣ工艺能够实现的矩形螺旋电感与ＦＥＴ实现的负阻电路，并对电路进行了详细的分析与计算机模拟，分析与模拟结果显示用单管ＦＥＴ实现的负阻电路结构简单，在谐振频率点，最大负阻值可达几千欧姆，而且，综合出的负阻电路完全可以用现有的ＭＭＩＣ工艺实现，为进一步设计微波有源滤波器打下了良好的基础。     

GaAs FET RF switches

The device parameter dependences of GaAs FET switch performance have been determined analytically and by two-dimension simulation. FET switch design would maximize the value of the switch quality factor while retaining the power handling capacity. Expressions for both the quality factor and power handling capacity are derived in terms of device parameters, and would enable such optimization to be performed.     

High speed normally-off GaAs MESFET integrated circuit

Normally-off GaAs MESFET integrated circuits with a maximum toggle frequency of 2.4 GHz were fabricated by conventional photolithography. The unfavourable effect of the surface depletion layer due to the large state density at the GaAs surface has been reduced by adopting the recessed gate FET structure.     

High-Speed Si-Bipolar and GaAs Technologies

Improvements in the design and fabrication of the basic transistor devices and improvements in circuit layout and design techniques have dramatically increased the performance of high-speed bipolar integrated circuits. Refinement of standard processes like lithography and the introduction of new processes such as low-pressure epitaxy and dry-etching techniques have largely contributed to the advancement of the device technology. GaAs int&égrated circuit technologies have rapidly developed over the last few years so that both analog and digital integrated circuits are now commercially available. These circuits all use the GaAs MESFET as the basic switching or modulating transistor. Integrated circuits based on more sophisticated heterostructure components, such as the heterojunction bipolar transistor or the modulation doped FET, are currently being developed. This paper will try to give an overview of present state of the art high-speed silicon bipolar technology and compare it to competing GaAs technologies. The most recent advances in oxide isolation technology which have led to the availability of 2.6 GHz dividers and the trend to self-aligned processes which can be used to achieve even smaller geometries will be described. On the GaAs side, the various GaAs-MESFET logic technologies and the heterojunction transistor technologies will be looked at regarding their present status and what can be expected in the near future. Most of the data will relate to monolithically integrated frequency dividers where a requirement for higher input frequencies combined with low power consumption exists.     

Temperature stability of ultrahigh-speed GaAs JFET ICs

Ultrahigh-speed digital integrated circuits (ICs) implemented with GaAs/int JFETs are confirmed to be reliable in a wide variety of temperatures. Divide-by-256/258 dual-modulus prescaler ICs using source-coupled FET logic (SCFL) circuits that can operate up to 9 GHz have temperature coefficients of operating frequency stability and input power sensitivity of -17.2 MHz/degree and +0.12 dBm/degree between -20 and +100°C, respectively. Direct-coupled FET logic (DCFL) circuits were also confirmed to have very small temperature coefficients. The variations of the maximum operating frequency and the input power sensitivity of the DCFL divide-by-4 divider IC are -1.93 MHz/degree and +0.47 dBm/degree, respectively, between -60 and +100°C. The variation in the threshold voltage of the JFET is -0.88 mV/degree which is very small for the temperature stability of GaAs digital ICs     

Modeling of discrete semiconductor devices

Numerical modeling established itself as a powerful tool for the analysis and design of discrete semiconductor devices and integrated circuits. The paper reviews the basic semiconductor equations, the physical internal mechanisms implemented in the present simulation programs and the numerical methods used to solve the nonlinear semiconductor equations. Selected results of numerical simulation of high frequency and high power discrete devices are given. The exemples comprise bipolar and FET devices made on Si or GaAs, operating in steady state or transient conditions and modeled in one or two dimensions.