GaAs Fet Ultrabroad-Band Amplifiers for Gbit/s Data Rate Systems

A novel ultrabroad-band amplifier configuration suitable for GaAs FET´s has been developed. The developed amplifier circuit operates as a capacitor-resistor ( C-R ) coupled mnpfifier circuit in the low-frequency range in which |S₂₁| for the GaAs FET´s is constant. It also operates as a lossless impedance matching circuit in the microwave frequency range in which |S₂₁| for the GaAs FET has a slop of approximately -6 dB/octave. Using this configuration technique, 800-kHz 9.5-GHz band (13.5 octaves), 8.6-dB gain GaAs FET amplifier modules have been realized. The amplifier module has 40-ps step response rise time. It also has low input and output VSWR. By cascading two-amplifier modules, 19-dB gain over the 800-kHz to 8.5-GHz range and 50-ps step response rise time were obtained. NF is lower than 8 dB over the 50-MHz to 6-GHz range.