From the small signal S-parameter of the packaged GaAs MESFET, the unilateral equivalent circuit can be derived approximately. Based upon this unilateral equivalent circuit, the problem of matching and gain compensation in the design of the broad band amplifier can be solved with the technique of model absorbing and the classical filter theory, after simple hand computation. The results of this method are checked by the computer simulation, and reoptimized for maximally flat gain. In this process the hand computation results are found good as initial point for optimization. Finally, the effect of each element's variation is considered.
