异质结双极晶体管高频噪声建模及分析

提出了一个T等效异质结双极晶体管高频噪声电路模型.该模型是对通常用在硅双极晶体管中的Hawkins噪声模型进行改进得到的,主要的改进包括发射极理想因子、发射极电阻、内部BC结电容、外部BC结电容和其它寄生元素对器件噪声性能的影响.为了从等效噪声电路模型中计算出精确的噪声参数,采用了噪声相关矩阵法来计算噪声参数,从而避免了在等效电路变换中可能产生的简化和复杂的噪声测量.进一步利用该模型分析了等效电路元素对器件最小噪声系数的影响,分析计算结果和物理解释一致.同时通过基于异质结双极晶体管器件物理的公式,给出了器件参数对器件最小噪声系数的影响.     

异质结双极晶体管高频噪声建模及分析

提出了一个T等效异质结双极晶体管高频噪声电路模型.该模型是对通常用在硅双极晶体管中的Hawkins噪声模型进行改进得到的,主要的改进包括发射极理想因子、发射极电阻、内部BC结电容、外部BC结电容和其它寄生元素对器件噪声性能的影响.为了从等效噪声电路模型中计算出精确的噪声参数,采用了噪声相关矩阵法来计算噪声参数,从而避免了在等效电路变换中可能产生的简化和复杂的噪声测量.进一步利用该模型分析了等效电路元素对器件最小噪声系数的影响,分析计算结果和物理解释一致.同时通过基于异质结双极晶体管器件物理的公式,给出了器件参数对器件最小噪声系数的影响.     

Impact of pad and gate parasitics on small-signal and noisemodeling of 0.35 μm gate length MOS transistors

Microwave noise performance of p and n-type MOSFETs fabricated on the. same wafer was investigated in order to study the effect of the pad and gate parasitic circuit elements on noise performance. At low drain currents, the gate parasitic circuit was involved in the modeling to explain the observed kinks and loops in the s-parameters. Simulation of the noise parameters for p and n-type devices, measured in the 2-26 GHz frequency range, was performed by using extracted small-signal models of the transistor in connection with parasitic pad and gate circuits. Under the bias far from the optimal one, the additional parasitic inductance in the gate circuit was found responsible for the degradation of the noise performance by exhibiting peaks in the noise parameters     

Extraction of device noise sources from measured data using circuitsimulator software

A procedure is presented for extracting the properties of device noise sources from experimental data. The extraction procedure can be implemented using commercially available circuit simulators. An example concerning a low-noise pseudomorphic high-electron-mobility transistor (HEMT) shows that the two noise sources extracted from experimental data are largely uncorrelated provided that parasitic elements are de-embedded from the measurement and that the sources are extracted in H-parameter format     

Characterization of Packaged Microwave Diodes in Reduced-Height Waveguide

A technique for the measurement of package parasitic and equivalent-circuit parameters of microwave semiconductor devices at the frequency of operation is presented. In this method a two-port coupling circuit is found which transforms the impedance measured in rectangular waveguide to the terminals of the equivalent circuit used to represent the semiconductor device. This approach combines known properties of radial transmission lines and of impedance measurement in the TE/sub 10/-mode full-height waveguide to obtain an analytical referencing technique for a diode mounted across a reduced-height waveguide. Application of this technique is illustrated by measurements of several varactor diodes.     

Instantaneous model of a MESFET for use in linear and nonlinearcircuit simulations

A formal approach for nonlinear modeling of FETs is presented. The intrinsic transistor is described by current and charge generators, that are instantaneously dependent on the two internal voltages. The extrinsic parasitic elements are also included. This instantaneous model is obtained from the small signal equivalent circuit computed at a number of bias points, by integration of the bias dependent elements. A program for using this model in nonlinear circuit analysis has been developed. The process has been carried out for two transistors, one being of low noise, and the other a power MESFET. Good agreement has been observed when comparing the nonlinear analysis with measured data. A solid-state power amplifier at 28 GHz has been designed using the power transistor, delivering 21 dBm at 1 dB compression point     

单边接地MESFET及其寄生效应的分析模型

本文介绍了栅宽为150μm和240μm两种单边接地MESFET制造工艺及其在单片电路中的应用。这种器件结构可减小器件占用的GaAs芯片面积,提高电路布线的灵活性,并已应用于12GHz低噪声放大器GaAs单片电路,取得了良好效果。本文也给出了这种器件寄生效应的分析模型,并计算讨论了栅靶、空气桥以及接地块等寄生元件对器件的散射参数和噪声参数的影响。     

The Simultaneous Measurement of Gain and Noise Using Only Noise Generators

The gain and noise of a linear two-port device can be measured simultaneously using two noise generators as the only signal sources. While this method is usable for measuring all linear two-port devices except those with high loss, it is particularly convenient for low-gain devices, for which it replaces three conventional measurements. The terms "minimum output temperature" and "standard output temperature" are introduced.     

Harmonic and two-tone intermodulation distortion analyses of theinverted InGa/InAlAs/InP HBT

Harmonic and two-tone intermodulation distortion analyses of the InGaAs/InAlAs/InP collector-up heterojunction bipolar transistor (HBT) are performed by a simple Ebers-Moll model. The parasitic elements of the equivalent circuit are extracted at zero bias by numerical optimization. A semianalytical approach is used to extract the intrinsic parameters of the small-signal equivalent circuit at nonzero bias points. Appropriate equations given by device physics are fitted to the bias variation of intrinsic parameters so that the Ebers-Moll model parameters can be extracted. Agreement between simulation and measurement of harmonic and intermodulation distortion is achieved     

电吸收调制器和DFB激光器集成器件的测量

提出了一种测量电吸收调制器和激光器集成器件芯片散射参数的新方法.根据电吸收调制器和封装寄生参数的等效电路模型,对测量的反射系数进行拟合,得到封装寄生参数和电吸收调制器的等效电路元件的参数值.通过分析发现测试封装寄生参数对电吸收调制器的测试结果有很大影响.去除了封装寄生参数的影响后,得到了调制器的反射和传输参数的真实频响特性     

A resonant-cap power combiner for two-terminal millimeter-wavedevices

A power combiner for three active two-terminal devices located under a common resonant cap is presented. An equivalent circuit with lumped elements describing the coupling between the devices is derived from a numerical finite-element simulation of the resonator. The applied monolithically integrated mounting technique for the active devices minimizes parasitic elements and gains high reproducibility and symmetry. Experimental results with GaAs IMPATT diodes on diamond heatsink of up to 500 mW at 91 GHz with a dc to RF conversion efficiency of 9.0% and excellent combining efficiency demonstrate the capability for power generation in the mm-wave region     

A New Look at Noise in Transferred Electron Oscillators

Low-frequency current and voltage fluctuations have been measured, and it has been confirmed that noise in packaged transferred electron devices (TED's) is due to three distinct noise mechanisms: flicker, generation-recombination, antd thermal noise. For transferred electron oscillators (TEO's), this low-frequency noise is upconverted into the microwave frequency range and adds to the intrinsic RF noise. We have found that between 1 kHz and 1 MHz off the carrier, temperature-dependent generation-recombination noise is the main contributor to the total noise. A model of a noisy TEO is presented. This model permits the calculation of AM and FM noise spectra from device and circuit parameters for measured low-frequency noise or the derivation of device characteristics from noise and circuit parameter measurements.     

Design of Microwave GaAs MESFET's for Broad-Band Low-Noise Amplifiers

As a basis for designing GaAs MESFET's for broad-band low-noise amplifiers, the fundamental relationships between basic device parameters, and two-port noise parameters are investigated in a semiempirical manner. A set of four noise parameters are shown as simple functions of equivalent circuit elements of a GaAs MESFET. Each element is then expressed in a simple analytical form with the geometrical and material parameters of this device. Thus practical expressions for the four noise parameters are developed in terms of the geometrical and material parameters. Among the four noise parameters, the minimum noise figure F/sub min/, and equivalent noise resistance R/sub n/, are considered crucial for broad-band Iow-noise amplifiers. A low R/sub n/ corresponds to less sensitivity to input rnismatch, and can be obtained with a short heavily doped thin active channel. Such a high channel doping-to-thickness (N/a) ratio has a potential of producing high power gain, but is contradictory to obtaining a low F/min/. Therefore, a compromise in choosing N and a is necessary for best overall amplifier performance. Four numerical examples are given to show optimization processes.     

Microwave Noise Characterization of GaAs MESFET's: Evaluation by On-Wafer Low-Frequency Output Noise Current Measurement

A simplified noise equivalent circuit is presented for submicron-gate-length MESFET's in the common-source configuration, consisting of five linear circuit elements: the gate-to source capacitance C/sub gs/, the total input resistance R/sub T/, the transconductance g/sub m/, the output resistance R/sub 0/, and a noise current source of spectral density S/sub io/ at the output port. All of these elements can be determined by on-wafer measurements, and the noise current can be measured at a low frequency. The minimum noise figure of the device calculated from this model, as well as the bias and frequency dependence of the noise figure, is shown to be in agreement with microwave noise figure measurements. Thus a technique has been established for determination of the minimum noise figure of a device solely by on-wafer measurements rather than by the usual microwave measurements. The proposed technique can be employed rapidly, conveniently, without the need for tuning, and at the wafer stage of device fabrication.     

Monte Carlo simulator for the design optimization of low-noiseHEMTs

A complete analysis of low-noise 0.1 μm gate AlInAs-GaInAs HEMT's has been performed by using a semiclassical Monte Carlo simulation. The validity of the model has been checked through the comparison of the simulated results with static, dynamic and noise experimental measurements of real HEMTs. In order to reproduce the experimental results, we have included in the model some important real effects such as degeneracy, surface charges, T-shape of the gate, presence of dielectrics and contact resistances. Moreover, the extrinsic parameters of the devices have been added to the usual intrinsic small-signal equivalent circuit, thus allowing the calculation of the real noise of the HEMTs (characterized using the extrinsic minimum noise figure). In this way, we make possible not only the comparison with the experimental noise results, but also the analysis of the influence of the parasitic elements, the device width or the number of gate fingers on the noise of the HEMTs. The reliability of the simulator allows us to realize “computer experiments” which will make faster and cheaper the optimization process of the device design     

Noise performance of gallium arsenide field-effect transistors

After a brief review of the noise-generating mechanisms intrinsic to the GaAs FET, an enumeration is given of the various parasitic elements associated with the FET which affect the noise performance. These elements include, among others, the gate metallisation and source contact resistances, drain-gate feedback capacitance, and source lead inductance. Numerous graphs are presented to illustrate the effects of these elements and the various design parameters on the noise performance. A comparison is made between the theoretically predicted and the measured noise performance of microwave GaAs FET's. The best state-of-the-art noise performance as reported by various laboratories is illustrated graphically for single-stage and multistage FET amplifiers. Finally, some speculation is attempted in regard to the possible reductions in noise figure to be expected from technological and design improvements of GaAs FET's.     

A new small-signal modeling approach applied to GaN devices

A new small-signal modeling approach applied to GaN-based devices is presented. In this approach, a new method for extracting the parasitic elements of the GaN device is developed. This method is based on two steps, which are: 1) using cold S-parameter measurements, high-quality starting values for the extrinsic parameters that would place the extraction close to the global minimum of the objective function for the distributed equivalent circuit model are generated and 2) the optimal model parameter values are searched through optimization using the starting values already obtained. The bias-dependent intrinsic parameter extraction procedure is improved for optimal extraction. The validity of the developed modeling approach and the proposed small-signal model is verified by comparing the simulated wide-band small-signal S-parameter, over a wide bias range, with measured data of a 0.5-/spl mu/m GaN high electron-mobility transistor with a 2/spl times/50 /spl mu/m gatewidth.