Experimental Studies of the Envelope Elimination and Restoration HF Power Amplifier Characteristics with Broadband Unmatched Load

The article describes results of experimental studies of 300 W HF power amplifier (PA) with Envelope Elimination and Restoration when it operating with broadband unmatched load. The description of developed and manufactured power amplifier is given. Experimental research confirms the proposed new extended method for taking into account losses in the PWM amplifier of the envelope path. Measurements of the quality and energy PA parameters for nominal and broadband unmatched load have been carried out. At rated load non-uniformity of the amplifier output power in the frequency range of 1.5 … 30 MHz does not exceed ± 12%, with the level of combination distortions not worse than minus 37.6 dB (relative to each tone, which is equivalent to 43.6 dB PEP). The average electronic efficiency of the amplifier on a two-tone signal in the range of 1.5 … 30 MHz is not less than 62.2%. PA output power with a load mismatch up to VSWR = 3 is not lower than 1.3*R
L
/VSWR and the level of combination distortions in the frequency range is within minus 30 … 40 dB.