Microwave Octave-Band GaAs FET Amplifiers

The design of microwave broadband amplifiers using the 1μ-gate GaAs field-effect transistors covering the 4-8 GHz and 7-14 GHz octave bands is presented. The braodband matching networks of these amplifiers consist of lumped and/or distributed circuit elements. Using analytical and computer-aided optimization techniques, a typical octave-band amplifier has been designed with a nominal power gain of 8 dB with a maximum deviation of ±0.07dB covering the 7-14 GHz band based on the measured scattering parameters of a 1μ GaAs FET chip. For a packaged 1μ GaAs FET, a 4-8 GHz band amplifier has been designed with a gain of 7.2 dB + 0.2 dB.