Design of broadband microwave FET-amplifiers

A new design method for broadband microwave FET-amplifiers is outlined. The design procedure utilizes the measured S-parameters of the FET, and the equalizing networks are developed from conventional matched Butterworth or Chebyshev lambda(go)/4-transformers using network transformations. The final equalizers are composed of cascaded commensurate transmission lines which are slightly shorter than lambda(go)/8. The theoretical and experimental results of 2-6 GHz and 2-8 GHz single-stage FET-amplifiers are given, showing that the proposed method, even without a correcting optimization, gives good amplifier performance. Gains of 10.1 + or - 0.6 dB and 8.4 + or - 0.6 dB were measured, respectively, in bands 2.0 - 6.0 GHz and 2.0 - 7.9 GHz with associated noise figures 3.1 + or - 0.1 dB and 3.8 + or - 1.1 dB.