Computer Calculation of Large-Signal GaAs FET Amplifier Characteristics

A simple and efficient method of GaAs FET amplifier analysis is presented. The FET is represented by its circuit-type nonlinear dynamic model taking into account the device's main nonlinear effects including gate-drain voltage breakdown. An identification procedure for extraction of the model parameters is described in detail and examples are given. The calculation of the amplifier response to a single-input harmonic signal is performed using the piecewise harmonic balance technique. As this technique is rather time-consuming in its original form, the optimization routine used to solve the network equations was replaced by the Newton-Raphson algorithm. Characteristics calculated with the use of the proposed method are compared with experimental data taken for a microwave amplifier using a 2SK273 GaAs FET unit. Good agreement at 9.5 GHz over wide ranges of bias voltage and input power levels are observed.     

Large-Signal Technique for Designing Single-Frequency and Voltage-Controlled GaAs FET Oscillators

A systematic procedure is described for designing fixed-frequency and voltage-tuned GaAs FET oscillators for optimum large-signal performance. The approach is based on the use of a large-signal FET model for de-embedding dominant device nonlinearities, leading to a method which is both accurate and simple to apply. The viability of the technique is demonstrated with a 17-GHz fixed-frequency oscillator and a 7.4 to 13.1-GHz varactor-tuned oscillator. Design considerations as well measured performance characteristics are discussed in detail.     

A Large-Signal Model for the GaAs MESFET

An analytic Iarge-signal model for the GaAs FET is described which relates the terminal currents to the instantaneous terminal voltages and their time derivatives. It incorporates the device geometry and semiconductor parameters as well as the device parasitic circuit elements. The model is fast and efficient when implemented on a computer and is in a form suitable for large-signal circuit design and optimization.     

自升温效应下的GaAs MESFET大信号模型

本文首先分析ＧａＡｓ ＭＥＳＦＥＴ在自升温效应下的升温幅度,然后结合器件电学参数随温度变化的特点,对器件的大信号等效电路模型进行了自升温效应下的修正。修正后的模型更准确地反映了器件的工作特性,应用于ＧａＡｓ ＭＥＳＦＥＴ功率ＭＭＩＣ ＣＡＤ中能进一步提高电路的设计精度。     

自升温效应下的GaAsMESFET大信号模型

分析了ＧａＡｓＭＥＳＦＥＴ在自升温效应下的升温幅度,结合器件电学参数随温度变化的特点,对器件的大信号等效电路模型进行了自升温效应下的修正。     

微波功率FET的大信号定模

叙述了一种新的功率ＦＥ定模方法,它利用在功率谐波测量与优化计算相结合,具有简单、方便、准确的优点．给出了实际测量结果。     

GaAs FET Applications for Injection-Locked Oscillators and Self-Oscillating Mixers

Injection-locked oscillators (ILO's) using GaAs FET's are described experimentally and theoretically, showing that a wider locking range can be obtained with transmission-type ILO's than with reffection-type, assuming Q/sub ext/, to the load to be the same in each case. Frequency-stabilized FET oscillators are discused in terms of the advantages gained by terminating the gate port by a 50-Omega load. Functioning as a self-oscillating mixer, the circuit showed a 9.5-dB (DSB) noise figure.     

A GaAs gate heterojunction FET

A new semiconductor-insulator-semiconductor field-effect transistor has been fabricated. The device consists of a heavily doped n-type GaAs gate with undoped (Al,Ga)As as the gate insulator, on an undoped GaAs layer. This structure gives the device a natural threshold voltage near zero, well suited for low-voltage logic. The threshold voltage is, to first order, independent of Al mole fraction and thickness of the (Al,Ga)As layer. The layers were grown by MBE and devices fabricated using a self-aligned technique involving ion-implantation and rapid thermal annealing. A transconductance of 240 mS/mm and a field-effect mobility of about 100 000 cm²/V-s were achieved at 77 K.     

GaAsFET大信号模型与参数提取

提出适用于功率ＧａＡｓＦＥＴ的新的大信号模型以及脉冲Ｉ－Ｖ和小信号Ｓ参数相结合的整体化参数提取方法。用研制出的大信号建模软件提取了功率ＦＥＴ的大信号模型参数，并用该模型模拟和测量了器件大信号Ｓ参数，结果完全一致。     

应用遗传算法提取GaAs场效应管小信号模型参数

利用阻抗矩阵法求出GaAs场效应管的小信号等效电路S参数,并提出应用遗传算法提取等效电路模型参数.该法具有收敛快速、精确度高的特点,使各个模型参数均能得到较为精确快速的提取.     

A Technique for Predicting Large-Signal Performance of a GaAs MESFET

A method is described for accurately predicting the nonlinear microwave performance of GaAs MESFET devices. The method utilizes time-domain analysis and is based upon the experimentally characterized bias dependence of device-circuit model elements. Precise predictions are made of fundamental and harmonic power levels up to 6 dB of gain compression.     

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。     

A functional GaAs FET noise model

It is the purpose of this paper to develop a theory upon which the design of low noise FET amplifiers can be based. This is not a fundamenta model of the noise mechanisms in GaAs FET's, but rather, an endeavor to relate physically measurable device capacitances and resistances to the device noise figure and optimum noise source impedance. I will be shown that the noise performance of an FET can be adequately described by two uncorrelated noise sources. One, at the input of the FET, is the thermal noise generated in the various resis, tances in the gate-source loop. This noise source is frequency dependent and it can be calculated from the equivalent circuit of the FET. The second noise source, in the Output of the FET, is frequency independent, and not recognizably related to any measured parameters. This output nise is a function of drain current and voltage. The decomposition of the FET noise into two uncorrelated sources simplifies the design of broad-band low noise amplifiers. Once the equivalent circuit of a device and its noise figure at one frequency are known, the optimum noise source impedance and noise figure over a broad range of frequencies may be calculated. For the device designer this model also may be helpful in balancing input-output noise tradeoffs.     

A new heterojunction gate GaAs FET

A new type of GaAs JFET having a heterojunction gate is proposed. The structure involves epitaxially grown layers of n-GaAs for the channel and of p-GaAlAs for the gate which can be easily delineated by the self-alignment technology using an overgrown p-GaAs. The potential advantages of the heterojunction structure for GaAs FET's over the conventional Schottky barrier are in the fewer masks for fabrication and the short channels expected. Some preliminary experimental results on fabrication technologies and dc characteristics of the new devices are described.     

功率GaAs FET

本文叙述了目前在研制功率GaAs FET过程中对器件的输出功率有比较重要影响的诸多因素,例如器件的几何结构、源引线寄生电感、热阻、击穿电压等等,以及对这些因素加以克服或限制的技术。折衷的结果将使所研制的器件具有良好的微波性能。     

A low-distortion K-band GaAs power FET

A K-band low-distortion GaAs power MESFET was developed by incorporating a pulse-type channel doping profile using molecular-beam-epitaxial technology and a novel 0.3-μm T-shaped gate. The low-distortion FETs offer about 10 to 15 dBc improvement in second-harmonic distortion compared to devices fabricated on a uniformity doped active layer. Significantly larger power load-pull contours are obtained with the low-distortion devices, indicating the improved linearity of these devices. In an 8-20-GHz single-stage broad-band amplifier, up to 10 dBc improvement in harmonic performance was achieved using the low-distortion device. This low-distortion device exhibits very linear transconductance as a function of the gate bias. A typical 750-μm-gate-width device is capable of 26 dBm of output power with 6 dB of gain, and power-added efficiency in excess of 35% when measured at 18 GHz. At 25 GHz, the device is capable of 24 dBm of output power with 5 dB associated gain     

GaAs FET upconverter for TV tuner

The critical part of a broad-band TV tuner, i.e., the upcon-verter was fabricated with simple GaAs IC's. The results obtained were: 1) "Pure" frequency spectrum due to double balanced mixer configuration. 2) Constant conversion gain of 12 ± 2 dB over the entire TV band (50-900 MHz). 3) Good linearity for large signals: Suppression of third-order intermodulation >40 dB for typical bias. 4) Low noise figure (typically 8 dB). These data demonstrate the feasibility of a monolithically integrated single-range TV tuner on GaAs.     

A Nonlinear GaAs FET Model for Use in the Design of Output Circuits for Power Amplifiers

A nonlinear equivalent circuit model for the GaAs FET has been developed based upon the small-signal device model and separate current measurements, including drain-gate avalanche current data. The harmonic-balance technique is used to develop the FET RF load-pull characteristics in an amplifier configuration under large-signal operation. Computed and experimental load-pull results show good agreement.     

A novel camel diode gate GaAs FET

A novel device utilizing the "camel diode" in place of a Schottky barrier gate has been demonstrated in GaAs grown by molecular beam epitaxy (MBE). The devices have a 7.5 µm channel length, 3 µm gate length, and a 280 µm gate width. The layers from which the devices are fabricated consist of a 0.15 µm GaAs layer doped to a level of 1.5 × 10¹⁷cm^-3to form the channel, and a 100 Å p+GaAs and a 400 Å n+ region to form the gate. Because of the long gate length, the electron velocity does not reach saturation, thus a transconductance of 80 mS/mm is obtained. A simple theory describing the device operation has also been developed.     

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.