Transformer coupled stacked FET power amplifiers

The development of high-power linear ultrahigh-frequency amplifiers is made difficult by the low impedance of the devices used in the output stage, which causes matching difficulties and high radio-frequency current levels. A stacked field-effect transistor (FET) configuration is shown to reduce these problems with its increased output impedance and lower current required for a given output power. A linear analysis of the stacked FET configuration is given. Two class A monolithic microwave integrated circuit amplifiers are developed and subjected to one- and two-tone tests to demonstrate the performance of the stacked FET as a power amplifier at 900 MHz     

A 4-W X-band compact coplanar high-power amplifier MMIC with 18-dB gain and 25% PAE

The performance of a compact coplanar microwave monolithic integrated circuit (MMIC) amplifier with high output power in the X-band is presented. Based on our 0.3-/spl mu/m gate-length GaAs power pseudomorphic high electron mobility transistor (PHEMT) process on 4-in wafer, this two-stage amplifier, having a chip size of 16 mm/sup 2/, averages 4-W continuous-wave (CW) and 25% mean power-added efficiency (PAE) in the X-band, with more than 18-dB linear gain. Peak output powers of P/sub -1dB/=36.3dBm (4.3 W) and P/sub sat/ of 36.9 dBm (4.9 W) at 10 GHz with a PAE of 50% were also measured. Compared to previously reported X-band coplanar high-power amplifiers, this represents a chip size reduction of 20%, comparable to the size of compact state-of-the-art microstrip power amplifiers.     

A 4-GHz Multistage Transistor Amplifier

Multistage microwave transistor amplifiers of simple construction have been developed. In these amplifiers, unit amplifiers of the same design are connected in cascade with short transmission lines inserted between each amplifier. The n-stage (three-, four-, five-, six-, and seven-stage) amplifiers designed for the 4-GHz band gave power gains n times that of the unit amplifier (4 dB) and flat bandwidths of about 1000 MHz. The stripline circuit of the amplifier is fabricated on alumina substrates in the usual way. The amplifier has the disadvantage of poor input and output impedance matching. However, this problem was solved by integrating isolators in the input and output ports of the multistage amplifier. Noise performance of the amplifier is also described.     

Use of Transistor-Simulated Inductance as an Interstate Element in Broadband Amplifiers

The properties of a transistor in the inverted common-collector connection, and the use of this connection as an interstage element in broadband amplifiers, are described. A simple amplifier synthesis procedure using a T model of the transistor, and experimental results obtained with a VHF amplifier, are presented. An extension of the synthesis using y-parameter characterization is also described; this procedure is useful in the synthesis of amplifiers consisting of many stages or when the validity of the simple T model is questionable. The use of the simulated inductance of the inverted common-collector connection in monolithic integrated circuits is considered and design examples of monolithic microwave amplifiers are given.     

基于ADS的微波低噪声放大器的设计与仿真

低噪声放大器包括输入匹配网络、微波晶体管放大器和输出匹配网络.微波晶体管放大器是设计中的核心部分.根据低噪声放大器设计的原理,提出技术指标要求,设计一个5GHz单级低噪声放大器,经过技术指标分析,采用Fujitsu公司的FHX35LG型HEMT场效应管晶体管.阐述了如何利用Agilent公司的ADS软件进行分析和优化设...     

Computer Aided Design of Wide-Band Integrated Microwave Transistor Amplifiers on High Dielectric Substrates

The problem of wide bandwidth and flat in-band gain response for microwave transistor amplifiers has been reduced to the optimization of a number of important variables from computer prepared design charts. Through the general flexibility of the computer-generated data, a large variety of amplifier responses are possible using distributed circuit matching networks. As experimental verification of the overall design procedure, single-stage and two-stage octave wide transistor amplifiers were fabricated on 1inch by 1inch and 1inch by 1/2 inch 20 mil thick alumina, respectively. The experimental data gained from these units showed excellent correlation with the computer predicted response.     

Computer Aided Design of Wide-Band Integrated Microwave Transistor Amplifiers on High Dielectric Substrates

The problem of wide bandwidth and flat in-band gain response for microwave transistor amplifiers has been reduced to the optimization of a number of important variables from computer prepared design charts. Through the general flexibility of the computer-generated data, a large variety of amplifier responses are possible using distributed circuit matching networks. As experimental verification of the overall design procedure, single-stage and two-stage octave wide transistor amplifiers were fabricated on 1 inch by 1 inch and 1 inch by 1/2 inch 20 mil thick alumina, respectively. The experimental data gained from these units showed excellent correlation with the computer predicted response.     

微波功率放大器的热管散热设计

随着微波功率放大器热功耗的增加和小型化,如何改善散热问题变得越来越重要,理想的热设计能够保证放大器长期工作。放大器在真空环境下以热传导和辐射散热为主,嵌入在盒体底部的热管具有很高的热传导率。放大器产生的热量以传导的方式传到盒体和热管,热管迅速把热量传导到散热器上,散热器的翅片通过辐射把热量散发出去。论述了在真空环境下微波功率放大器热管散热的设计方法,用ICEPAK CFD热分析软件进行热仿真。微波放大器通过热真空试验,可以工作正常,实验表明热管散热是真空环境下大功率放大器热设计的有效方法。     

Graphic Design of Matching and Interstage Lossy Networks for Microwave Transistor Amplifier

A graphical design method for Iossless and lossy gain-compensating networks is presented, and the advantages of the use of this technique in the construction of microwave transistor amplifiers are discussed. The method is based on the use of a set of constant S/sub ji/ circies plotted on the Smith Chart, and is easily automated on a personal computer. Two applications are presented: a two-stage amplifier with 20 dB in the 100-1100-MHz band and an ultra-broad-band lossy matched amplifier stage with 4 dB in the dc-16-GHz band.     

Messmethoden zur Charakterisierung von Mikrowellenleistungstransistoren

For first try designs of microwave power amplifiers it is necessary to know the entire physical behaviour of the used components with high accuracy. The attention should be directed especially to the center component of these circuits, the power transistor, whose nonlinear characteristics have an essential impact on the behavior of the whole amplifier. This article gives an overview of current methods of measurement for microwave power transistor characterization. Furthermore a measurement system is presented, capable of characterizing microwave power transistors within a frequency range from 30 kHz to 8.7 GHz at bias current up to 7.5 A including self heating effects.     

Design and performance analysis of mismatched Doherty amplifiers using an accurate load-pull-based model

An active load-pull-based large-signal modeling approach, suitable for designing and optimizing load modulated amplifiers such as Doherty or linear amplification using nonlinear components based amplifiers, is proposed. A Doherty amplifier was designed by optimizing the dynamic loads seen by the amplifier's transistor using a large-signal load-pull-based behavior model built into computer-aided-design software. Simulation and measurement results showed good agreement, while results obtained using an empirical model of this transistor demonstrated discrepancies. The load-pull-based model was then used to study performance degradation of the Doherty amplifier when load impedance was moved out from the perfect 50 /spl Omega/. It has been shown that the load mismatch can greatly affect the linearity and efficiency performance of the amplifier unless its phase is controlled and kept within a specific range. A load mismatch system level compensator scheme, capable of restituting the linearity loss and maintaining the power-added efficiency close to its maximum range, is proposed.     

Computer aided design of wide-band integrated microwave transistor amplifiers on high dielectric substrates

The problem of wide bandwidth and flat in-band gain response for microwave transistor amplifiers has been reduced to the optimization of a number of important variables from computer prepared design charts. Through the general flexibility of the computer-generated data, a large variety of amplifier responses are possible - using distributed circuit matching networks. As experimental verification of the overall design procedure, single-stage and two-stage octave wide transistor amplifiers were fabricated on 1 inch by 1 inch and 1 inch by ½ inch 20 mil thick alumina, respectively. The experimental data gained from these units showed excellent correlation with the computer predicted response.     

A 10 Gb/s AlGaAs/GaAs HBT high power fully differential limitingdistributed amplifier for III-V Mach-Zehnder modulator

High power, high frequency linear distributed amplifiers are available commercially which provide high power single-ended drive capability from a single-ended source. The signal source can be either analog or digital. Such amplifiers must have stringent gain and phase response requirement over a wide bandwidth in order to maintain good eye quality of the signal. A limiting amplifier, with less stringent bandwidth requirement than analog amplifiers, can be used to amplify pure digital signal source. The purpose of this paper is to present a high power, fully differential limiting distributed amplifier operating at 10 Gb/s. The amplifier has been fabricated with both AlGaAs/GaAs and InGaP/GaAs heterojunction bipolar transistor (HBT) processes. The amplifier is designed to drive any 50 Ω system. In particular, this amplifier is intended to drive a III-V Mach-Zehnder modulator     

Integrated complementary HBT microwave push-pull and Darlingtonamplifiers with p-n-p active loads

The authors report the microwave results of complementary heterojunction bipolar transistor (HBT) amplifiers that integrate both n-p-n and p-n-p devices on the same chip using selective molecular beam epitaxy (MBE). An HBT wideband amplifier utilizing the Darlington configuration and implementing a p-n-p active load has a gain of 7.5 dB and a bandwidth from DC to 2.5 GHz. A complementary push-pull amplifier has a saturated output power of 7.5 dBm at 2.5 GHz     

A monolithic silicon wide-band amplifier from DC to 1 GHz

Monolithic integration of a wide-band amplifier with uniform gain from dc to 1 GHz is described. By choosing an essentially simple circuit both for construction and evaluation it is shown that the collective application of microwave transistor diffusions, double layer interconnections, beam leads, air isolation, and microstriplines on ceramic substrates extends the range of operation to beyond 1 GHZ. Gain values of 12 dB flat within 0.5 dB for a two- stage amplifier and nearly 50 dB flat within 1 dB for cascaded amplifiers from low frequencies to 1 GHz are achieved. The direction for further technological improvements is indicated.     

Treatment of noise-figure calculations in microwave transistor amplifiers

In the design of microwave transistor amplifiers it is frequently necessary to use optimisation techniques to achieve best results. In this context it is useful to be able to evaluate readily noise figure and its sensitivity with respect to elements in the amplifier network. Efficient methods for such computations are discussed in this communication.     

2–8 GHz 8-W Power Amplifier MMIC Developed Using MSAG MESFET Technology

Design approach and test data for a two-octave bandwidth HPA developed using GaAs based multifunction self aligned gate metal semiconductor field effect transistor with multilevel plating monolithic microwave integrated circuit (MMIC) technology are presented. A low loss matching design technique was used in the development of a two-stage power amplifier. The broadband amplifier has exhibited 8 W power output and better than 16% PAE over the 2.0-8.0 GHz frequency range. To our knowledge, these results represent the state-of-the-art in output power for multi-octave S/C-band power MMIC amplifiers.     

LDMOS微波功放器设计

文章首先从功放器的合理选择、功放器工作状态的确定和功放器匹配电路的设计三个角度讨论了在设计功率放大器电路方案时应该考虑的不同因素。然后以实际项目需要的微波功率放大器为例,根据产品的技术指标要求,结合在做微波放大器设计和生产中积累的经验,设计了一款工作在P波段,典型增益在15 dB的功率放大器,通过合理选择功放器及其工作状态,设计电路结构、阻抗匹配,最终该功放具有输出功率稳定、增益平坦度小、线性度高、可靠性高等特点。     

X- and Ku-band amplifiers with GaAs Schottky-barriers field-effect transistors

During recent years significant progress has been made in GaAs technology and the GaAs Schottky-barrier field-effect transistor now shows outstanding microwave gain and noise properties. Two experimental microwave amplifiers demonstrate that the device is very well suited for broad-band applications and that large bandwidth in the X- and Ku-band can be obtained with simple circuits. The first of the two three-stage amplifiers realized was optimized with respect to noise and a noise figure of 3.8 dB was obtained at 8 GHz; the maximum gain is 17.5 dB at 8.3 GHz and the 3-dB bandwidth is 1.3 GHz. The second amplifier has a maximum gain of 11.5 dB at 11.5 GHz. The gain is greater than 8.5 dB in the range 9.5-14.3 GHz.