Microwave Power GaAs FET Amplifiers

The development of broad-band microwave amplifiers using state-of-the-art GaAs power FET's covering the 6-12-GHz frequency band is presented. A unique circuit topology incorporating an edge-coupled transmission line section for both impedance matching and input/output dc blocking is described. The microstrip circuit design of an X-band 1-W 22-dB-gain GaAs FET amplifier is also discussed. Microwave performance characteristics such as intermodulation, AM-to-PM conversion, and noise figure are included.     

GaAs Dual-Gate FET for Operation Up to K-Band

A high-frequency equivalent circuit model of a GaAs dual-gate FET and analytical expressions for the input/output impedances, transconductance, unilateral gain, and stability factor are presented in this paper. It is found that the gain of a dual-gate FET is higher than that of a single-gate FET at low frequency, but it decreases faster as frequency increases because of the capacitive shunting effect of the second gate. A dual-gate power FET suitable for variable gain amplifier applications up to K-band has been developed. At 10 GHz, a I.2-mm gatewidth device has achieved an output power of 1.1 W with 10.5-dB gain and 31-percent power-added efficiency. At 20 GHz, the same device delivered an output power of 340 mW with 5.3-dB gain. At K-band, a dynamic gain control range of up to 45 dB was obtained with an insertion phase change of no more than +-2 degrees for the first 10 dB of gain control.     

Design of Broad-Band Power GaAs FET Amplifiers

A model is presented for the drain-gate breakdown phenomenon of GaAs FET's, based on experimental results. this breakdown model is added to a previously published large-signal model and incorporated in a powerful computer-aided design program called LSFET. The program is capable of searching for the optimum power load for an FET and simulating the power performance of multistage amplifiers. The design of power amplifiers is discussed in detail, using the knowledge gained from LSFET. Data is presented from a fabricated monolithic broad-band power amplifier chip showing good agreement between measured results and simulated curves.     

NEDI'''' C Band GaAs FET Power Amplifiers

<正> Application Mainly used as the replacement of travelling wave tube in microwave communication system and a power amplifier in a satellite communication earth station. Features It employs GaAs MESFETs and a microstrip structure, with Iow power consumption and high reliability.     

Design of Broad-Band GaAs FET Power Amplifiers

A direct systematic approach to designing broad-band GaAS FET power amplifiers for optimum large-signal gain performance is described. Assets of this approach include its accuracy in predicting large-signal amplifier performance and its basic simplicity. The implementation of the technique is facilitated by having to measure large-signal device bebavior at only one single frequency. The practicability of the method is demonstrated through comparisons between measured and predicted results.     

A K-Band GaAs FET Amplifier with 8.2-W Output Power

An 8.2-W GaAs FET amplifier with 38.6+-0.5-dB gain over a 17.7-19.1 GHz frequency band has been developed. This amplifier combines the outputs of eight multistage amplifier modules utilizing a radial combiner. This state-of-the-art power level has been achieved with AM/PM of less than 2°/dB. The third-order intermodulation products at 1-dB gain compression were 20 dBc, and variation in group delay over the frequency band was less than +-0.25 ns. Tests show that the amplifier is unconditionally stable and follows the graceful degradation principle.     

宽带GaAs FET功率放大器的计算机辅助设计

本文叙述了采用静态法模拟GaAs FET大信号模型和以该大信号模型设计宽带GaAsFRT功率放大器的方法.在分析电路时,提出了一种对非线性电路进行交流大信号稳态分析的有效方法:时一频转换循环迭代法.编写了一个优化设GaAs FET功率放大器的计算机程序GFPA.采用该程序设计制作了一个单级宽带GaAs FET功率放大器.在未作任何调整的情况下,该放大器的实测性能与其理论计算符合较好.     

乘子法及C波段宽带GaAs FET放大器

本文探讨一种新乘子迭代的乘子法.并用于计算机优化设计有约束条件下的GaAsFET放大器.乘子法中,为使乘子λ~(?)收敛到有限值,文章建议应选择参数C初始值.使之与被优化目标函数权因子的最大值在同一数量级.作者将研制成功的二个三级GaAs FET放大器进行级联后测试.在3～7.4GHz频率范围内.得增益49=2.5dB,最大噪声系数3.6dB(典型3.3dB),1dB增益压缩点的最小输出功率-13dBm.实验证实乘子法是行之有效的.文中给出基于匹配网络综合理论分析得到的三级GaAs FET放大器新的拓扑类型及网络元件的计算机优化值.     

大功率GaAs FET偏置电路设计中的有关问题

现代雷达的发展方向是多功能化、小型化,固态发射机以工作寿命长、可靠性高、体积小等优点被广泛使用.本文主要总结了固态发射机设计中部分大功率GaAs FET偏置电路的设计经验.     

A Novel K-Band Balanced FET Up-Converter

The performance of the K-band balanced FET up-converter is described. A novel circuit configuration effective in enhancing conversion gain in the FET up-converter is proposed. An analysis using a simplified circuit model shows the effect of LO feedback in the balanced circuit. A conversion gain of 0.9 dB was experimentally obtained at 20 GHz. Maximum output power was 15.9 dBm.     

8GHz功率场效应放大器

本文叙述了用于微波中继通讯的功率GaAs FET放大器.介绍了设计方法和研制结果,8GHz下获得输出功率600mW、增益大于34dB、线性度良好的结果,并已经用于微波中继通讯无人站中.     

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。     

K-Band High-Power Single-Tuned IMPATT Oscillator Stabilized by Hybrid-Coupled Cavities

A K-band high-power and highly stable power source has been developed using a cavity-stabilized IMPATT-diode oscillator followed by a one-stage high-power reflection-type IMPATT-diode amplifier. The power source shows an output power of 0.7 W, a temperature coefficient of 6x10/sup -7/ / /spl deg/C, and an FM noise level of 92-Hz rms/1-kHz BW at 100 kHz from the carrier. To achieve a highly stable oscillation, free from mode jumping, a new hybrid-coupled cavity circuit with a passivating absorber is applied to stabilize the oscillation. The high-power amplifier is designed using a measured large signal device admittance and a power-adding concept.     

4GHz 80K FET放大器

本文从低噪声FET放大器的实际设计出发,分析了输入匹配电路对噪声性能的影响.从放大器的实际结构讨论了影响放大器噪声性能的因素.使用南京固体器件研究所研制的WC61GaAs MESFET,在3.7～4.2GHz下,得到的结果为:两级放大器增益28dB,三级放大器增益40dB,带内噪声温度小于80K,最小噪声温度为77K.     

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.     

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.     

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.     

GaAs FET distributed amplifier

The design and construction of a GaAs FET distributed amplifier with a bandwidth of 6 GHz is described The amplifier provides an input VSWR of less than 1.8:1 and noise figure of 3?6 dB The possibility of bandwidth extension is discussed.     

GaAs microwave power FET

A design consideration for an X-band GaAs power FET, features of the fabrication process, and electrical characteristics of the FET are described. Interdigitated 53 source and 52 drain electrodes and an overlaid gate electrode for connecting 104 Schottky gates in parallel have been introduced to achieve a 1.5-µm-long and 5200-µm-wide gate FET. A sheet grounding technique has been developed in order to minimize the common source lead inductance (L8= 50 pH). The resulting devices can produce 0.7-W and 1.6-W saturation output power at 10 GHz and 8 GHz, respectively. At 6 GHz, a linear gain of 7 dB, an output power of 0.85 W at 1-dB gain compression and 30-percent power added efficiency can be achieved. The intercept point for third-order intermodulation products is 37.5 dBm at 6.2 GHz.     

Cryogenic GaAs FET amplifier

An extremely low noise, cryogenic, gallium arsenide field-effect-transistor amplifier has been developed for the frequency range 3.7 to 4.2 GHz. The amplifier has an average noise temperature of 25 K, with an associated gain of 21 dB, when cooled to a physical temperature of 77 K.