Cascode linear power amplifier

Abstract

The cascode connection of RF transistors has generally been done at high frequencies and low power. The cascode amplifier described in this paper utilizes high power RF transistors to obtain an extremely linear amplifier capable of 50 watts output. The requirements are that intermodulation distortion products be less than 40db and that the corresponding harmonics at any frequency be less than 40db. The frequency range is 1.6-28MHz. Class A operation has been selected for minimizing IM products and harmonics. A single low pass filter is utilized to keep harmonics at the high end of the band within the 40db specification.