Accession Number : ADA192974

Title :   Microwave Amplifiers.

Descriptive Note : Final rept. 7 Sep 84-30 Sep 87,

Corporate Author : ILLINOIS UNIV AT URBANA ELECTROMAGNETICS LAB

Personal Author(s) : Chuang, S L ; Lee, S W ; Lee, S M ; Ahn, D

PDF Url : ADA192974

Report Date : 25 Jan 1988

Pagination or Media Count : 147

Abstract : A two-dimensional model for GaAs MESFET has been developed to study its linear and nonlinear microwave performances. The I-V characteristics curves for the intrinsic GaAs MESFET are obtained and compared with those for experimental measurements. Scattering parameters are calculated using the complete microwave model, which includes the intrinsic model and the parasitic elements, and compared with experimental findings. Reasonably good agreement between our calculation and the experimental measurements are obtained. Microwave nonlinear performances for a GaAs MESFET are simulated based on the large signal model. The microwave ouput signal in the time domain is simulated with two large input signals of different frequencies. Then the output power at the fundamental, first-order, second-order, and third-order harmonics are obtained. The power gains for the fundamental and the third-order spur at different bias points are calculated. Various HEMT models have been investigated. Three analytical models, the classical Fermi-Dirac, the two-level two-dimensional Electron Gas (2DEG) and the extended 2DEG models, are employed to study the electron concentration at the heterointerface where the electrons have very high mobility which is responsible for the ultra-fast transistor action due to the separation of electrons and ionized donors. Finally, the microwave applications of the quantum-well Stark effect are investigated.

Descriptors :   *MICROWAVE AMPLIFIERS, *ELECTRON GAS, *SCATTERING, *TRANSISTORS, CONCENTRATION(COMPOSITION), DONORS(MEDICINE), ELECTRONS, EXPERIMENTAL DATA, HARMONICS, HIGH RATE, INPUT, IONIZATION, MATHEMATICAL MODELS, MEASUREMENT, MICROWAVE AMPLIFIERS, MICROWAVES, MOBILITY, MODELS, OUTPUT, PARAMETERS, POWER, SEPARATION, SIGNALS, TIME DOMAIN, TWO DIMENSIONAL

Subject Categories : Electrical and Electronic Equipment
      Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE