Stacked gallium arsenide FET RF power amplifiers.

摘要

This dissertation deals with the design, simulation, analysis, and experimental testing of a new device configuration for GaAs high frequency power amplifiers called the stacked FET. In this configuration the output drain to source connections of the FETs are placed in series forming a stack of outputs extending from V{dollar}sb{lcub}rm dd{rcub}{dollar} to ground, while the input signal is fed to each device through an isolation transformer. The stacked FET offers an improved output impedance, increased system efficiency, and can operate from a much higher drain to source voltage than a standard design.; Two test MMIC amplifiers have been designed and simulated using the HP/EESOF Libra harmonic balance simulator, and fabricated using Nortel's cellular GaAs sagfet process. These MMICs were combined to form three experimental power amplifiers: a single FET amplifier, a two FET stack, and a four FET stack. The experimental amplifiers were tested using linear S parameter measurements, one tone tests at 900 MHZ, and two tone tests at 899.5 MHz and 900.5 MHz, and the results are compared with the results from the harmonic balance simulation.; A new large signal analysis is proposed based on the describing functions used in nonlinear system theory. Describing functions for the one and two tone tests are developed using the dc transfer characteristic of the MESFET which is derived while it is connected to the maximum output power load resistance. The fundamental, harmonic, and intermodulation powers are predicted and compared with the measured amplifier results and with the harmonic balance simulation results.