Comments on "X-band 0.5, 1, and 2 Watt power amplifiers with marked improvement in power-added efficiency

For the original article see ibid., vol.38, no.6, p.707-11 (1990). Power-added efficiency results from MMIC amplifiers which were designed, fabricated, and tested based on efforts reported in the above-named work have caused a reassessment of measurements made for that work. The new MMIC amplifiers exhibited a maximum power-added efficiency of 32% in X-band at 1-W output power. These results are significantly lower than the 53% average power-added efficiency for the 1-W hybrid amplifiers previously reported. In a recent experiment on one of the original hybrid amplifiers, the previous efficiency results could not be replicated or confirmed. It is prudent to assume that the earlier amplifier efficiency measurements were in error.<>