A novel FET model including an illumination intensity parameter forsimulation of optically controlled millimeter-wave oscillators

This paper demonstrates an illuminated FET model including an illumination-intensity parameter for simulation of optical characteristics of microwave and millimeter wave integrated circuits (MMIC's). Modeling for an illuminated GaAs MESFET and an InP high electron-mobility transistor (HEMT), and analysis and experimental results from optically controlled microwave and millimeter-wave hybrid integrated circuit (HIC) and MMIC oscillators are discussed. The proposed illuminated FET model was able to explain the photoresponse of both the GaAs MESFET and the InP HEMT, and the photooperation of their circuits     

Computer-Aided Synthesis of Lumped Lossy Matching Networks for Monolithic Microwave Integrated Circuits ( MMIC's)

A systematic computer-aided synthesis (CAS) technique of lumped Iossy matching networks is presented in this paper. This exact synthesis procedure can take arbitrary finite quality factor Q for each lumped element in the matching network and therefore facilitate the circuit design for monolithic microwave integrated circuits (MMIC's) where the loss of the passive elements is too large to be neglected. The gain-band-width limitations of some useful lumped Iossy matching networks are discussed in detail and are summarized in a set of gain-bandwidth constraint plots. An interactive computer program LUMSYN is developed to solve this lumped Iossy synthesis problem. LUMSYN is a general-purpose CAS program which can be used by microwave circuit designers with limited background in network synthesis to carry out Iow-noise and power amplifier designs in MMIC's. Finally, a design example of broad-band monolithic microwave low-noise amplifier using a state-of-the-art low-noise submicron gate-length GaAs MESFET is presented to illustrate the computer-aided synthesis of MMIC amplifiers.     

Accelerated life testing and failure analysis of single stage MMICamplifiers

Single stage monolithic microwave integrated circuit (MMIC) amplifiers have been high temperature accelerated life tested under DC+RF biasing conditions. Most of the circuits failed parametrically due to a gradual decrease in RF output power. Failure analysis revealed localized reduction of the gate breakdown characteristics of the metal semiconductor field effect transistor (MESFET). This was occurring through degradation of the GaAs surface Si₃N₄ passivation layer interface in the channel region of the MESFET, resulting in a reduction in the number of surface states. The few catastrophically failed MMIC's are believed to represent a special case of this degradation process which occurred very rapidly. In contrast to the transistor, the other components of the circuits were unchanged following life test     

Optically induced measurement anomalies with voltage-tunableanalog-control MMIC's

Monolithic microwave integrated circuits (MMIC's) may be measured under relatively high-intensity lighting conditions. Later, when they are packaged, any anomalies found in subsequent measurements could be attributed to unwanted parasitics or box modes associated with the packaging. However, optical effects may not always be considered by radiofrequency (RF) and microwave engineers. For the first time, a qualitative assessment is given for the effects of photonic absorption on three broad-band voltage-tunable analog-control circuits. Each circuit has a different function, with each field-effect transistor (FET) operating in a different mode: a hot FET in a variable-gain amplifier, a cold FET in an analog attenuator, and an FET varactor in an analog phase shifter. All three circuit functions have been implemented using two different FET-based technologies. The first with ion-implanted 0.5-μm GaAs metal-semiconductor FET's (MESFET's) in circuits operating at either 3 or 10 GHz. The second employs epitaxially grown 0.25-μm AlGaAs-InGaAs pseudomorphic high electron-mobility transistors (HEMT's) in circuits operating at 38 GHz. All the MMIC's were fabricated using commercial foundry processes and illuminated under conventional optical microscope lighting conditions. Prominent error peaks have been found at bias points unique to the three different circuit topologies. Large error peaks are found with the MESFET-based circuits, while much smaller error peaks are achieved with the corresponding pseudomorphic HEMT (pHEMT) based circuits     

The design of tuned front-end GaAs MMIC optical receivers

Recently, much interest has been shown in the design of very low noise tuned front-end optical receivers for use in lightwave systems. This paper looks at the accurate design of such receivers. Simplified design expressions are presented for a number of tuning configurations with theoretical and measured results being presented. The designs were realized as GaAs monolithic microwave/millimeter-wave integrated circuits (MMIC's)     

High frequency gallium arsenide linearised transconductor for communications

The authors propose a linear transconductor circuit for implementation in GaAs MESFET technology. The application of the transconductor to linear microwave amplifiers and linear drive circuits for optical systems is described.<>     

Large-signal model of picosecond FETs and measurement of the stepresponse

An FET large-signal model is developed for the time-domain computer-aided design (CAD) of ultrafast circuits. Numerical 2-D look-up tables describe the nonlinear parameters; a DC and microwave FET characterization as a function of bias voltage, followed by parameter extraction, completely determines the tables of parameters. The model can be implemented with simulators handling 2-D tables and applied to commercial transistors without a detailed knowledge of the internal structure of the device. The step response of an NEC710 MESFET is measured and compared with the prediction of the model, demonstrating its accuracy in representing switching waveforms and transient phenomena in the range covering tens of picoseconds. The 20-ps switching time of the NEC710 shows that the modeling methodology, measurement, and simulation are adequate for studying picosecond transient phenomena in single transistors     

Uniplanar MMIC Hybrids--A Proposed New MMIC Structure

A new "uniplanar" circuit configuration for monolithic microwave integrated circuits (MMIC's) has been proposed. It uses a combination of coplanar waveguides and slotlines on one side of the substrate. The key components for the uniplanar structure are air bridges, which provide T junctions and transitions from coplanar waveguides to slotlines or vice versa. Novel hybrid circuits such as a magic T and a branch-line coupler have been fabricated and tested at K-band, and good performance has been achieved. This new circuit configuration is promising for applications in other microwave circuits.     

An accurate photonic capacitance model for GaAs MESFETs

A new set of pseudoempirical equations is presented in order to simulate the optical and bias dependencies of GaAs MESFET junction capacitances, which is valid for the whole I-V plane. The variations induced in the small-signal equivalent circuit by the optical illumination are extracted from on-wafer scattering parameter measurements. New linear and quasi-logarithmic variations versus the incident optical power are shown for gate-drain and gate-source (Cgd and Cgs) capacitances. Furthermore, experimental results are in very good agreement with the simulated values for a wide range of optical power and bias conditions. Large signal MESFET models show a better fit with measured S-parameters than those previously published, leading to a greater degree of confidence in the design of photonic monolithic microwave integrated circuits     

GaAs MESFET微波非线性电路全频域谐波平衡分析

根据Fourier分析理论推导了全频域分析微波非线性电路的方法,此方法简单明了,适合于分析微波大信号强非线性电路.用此方法对GaAs MESFET微波非线性电路进行分析,给出了实用的分析计算结果.     

GaAs HBT's for microwave integrated circuits

The status of the microwave GaAs heterojunction bipolar transistor (HBT) technology is reviewed. Microwave circuits for advanced military and commercial systems continue to increase their dependence on the performance, functionality, and cost of active components fabricated using solid-state technology. The performance advantages provided by GaAs HBT's, for several critical circuit applications, have stimulated a worldwide development activity. Progress in HBT device technology and microwave circuit applications has been extremely rapid because of the broad availability of III-V compound semiconductor epitaxial materials and prior experience with GaAs field-effect transistors (FET's) and monolithic microwave integrated circuits (MMIC's). The great flexibility of HBT's in microwave circuits makes them prime candidates for applications in complex multifunctional microwave/digital IC's in next-generation systems     

An improved GaAs MESFET equivalent circuit model for analog integrated circuit applications

An improved equivalent circuit model of a gallium-arsenide (GaAs) MESFET that is optimized for the design and analysis of precision analog integrated circuits is described. These circuits entail different modeling requirements from digital or microwave circuits, for which existing equivalent circuit models are optimized. Improved techniques are presented to model the drain-to-source conductance, device capacitance, and the functional dependence of drain-to-source current.     

A fully analytical AC large-signal model of the GaAs MESFET fornonlinear network analysis and design

A fully analytical version of an AC large-signal model for the GaAs MESFET is presented. The source model is based on basic principles and the actual physics and geometry of the device. The analytical version was developed by curve fitting the analytical expressions to the source model. The accuracy of the model for microwave circuits is demonstrated using simulation examples of a power amplifier and a mixer     

用改进的非线性电流源法分析微波振荡器的稳态响应

本文提出用改进的非线性电流源法和振荡器的振荡条件相结合,进行微波FET振荡器非线性分析的方法.非线性电流源法已经被证明为分析微波振荡器的一种行之有效的方法.但是,当电路中含有多维非线性元件时(例如FET中的I_(d5)(V_(g5),V_(d5)),以往的非线性电流源法就显得无能为力.在此,我们将对非线性电流源法进行改进,并将它运用到微波FET振荡器的非线性分析中.改进的非线性电流源法能够有效地处理含有多维非线性元件电路的分析问题,从而大大提高了非线性电流源法的分析能力和实用性,扩大了其应用范围.     

Yield considerations for ion-implanted GaAs MMIC's

An ion-implantation based process is described for fabricating GaAs monolithic microwave integrated circuits (MMIC's) incorporating active devices, RF circuitry, and bypass capacitors. Low ohmic contact resistance and good control of metal-insulator-metal (MINI) capacitance values is demonstrated and some factors affecting FET and capacitor yield are discussed. High dc yield of typical amplifier circuits is shown indicating that this process has the potential for achieving very high overall yields in a production environment. Good yield of functional MMIC modules with multicircuit complexity is projected.     

Yield Considerations for Ion-Implanted GaAs MMIC's

An ion-implantation based process is described for fabricating GrAs monolithic microwave integrated circuits (MMIC's) incorporating active devices ,RF circuitry, and bypass capacitors. Low ohmic contact resistance and good control of metal-insulator-metal (MIM) capacitance values is demonstrated and some factors affecting FET and capacitor yield are discussed. High dc yield of typical amplifier circuits is shown indicating that this process has the potential for achieving very high overall yields in a production environment. Good yield of functional MMIC modules with multicircuit complexity is projected.     

Analytical model for optically generated currents in GaAs MESFETs

The MESFET as an optically sensitive microwave element in MMICs has attracted much attention. The theoretical modeling of the device, however, needs more consideration. The authors propose an analytical model for the illuminated MESFET, complete in that all major contributions to the optical response are considered. The dependence of the response on bias conditions, the wavelength and intensity of the optical input, and the particulars of device structure, are incorporated in the model. The importance of the internal photovoltaic effect, which has not been properly modeled previously, is emphasized. The novel theoretical model is verified by experimental results     

Large-Signal Microwave Performance Prediction of Dual-Gate GaAs MESFET Using an Efficient and Accurate Model (Short Paper)

This paper presents a microwave large-signal model for the dual-gate MESFET. The model enables prediction of device performance in small-signal and large-signal circuits. The model is an extension of a previously developed model for the ordinary MESFET. It relies on basic principles, thus correlating the device geometry and physical parameters to its performance. The speed and accuracy of the model are demonstrated by calculating three types of device performance: dc curves smell-signal scattering parameters, and huge-signal simulation of an amplifier. Good agreement was achieved between calculated and measured perfomance. The computed results are presented for comparison only, and no attempt was made to present a comprehensive analysis of the device performance.     

Simulation and Modeling-implementing GaAs device models with SPICE

A method for evaluating the accuracy of a device model and its tendency toward convergence problems before implementing it as a SPICE primitive is presented. Two different GaAs MESFET models suitable for analyzing nonlinear analog and microwave circuits are implemented using generic SPICE primitives. It is shown that no modification to the SPICE program is required. Controlled sources are extensively used in implementing the models using this method     

MMIC compatible lightwave-microwave mixing technique

The work presented here concerns the mixing of a microwave signal with a modulated optical signal in a MESFET. A brief theoretical analysis of the mixing mechanism is given in terms of the input signal parameters and device characteristics. Experimental results for the IF response of the MESFET as a function of RF frequency, incident optical power, optical modulation depth and gate bias voltage are shown. The IF response and the noise figure of the MESFET below 700 MHz were smaller than those of a p-i-n detector/Schottky mixer combination