PRF-1150 13.56MHz 1kW Class E RF Generator

Doc #9200-0255 Rev 1

 2002 Directed Energy, Inc.

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Figure 10: Drain Waveform @ U3, Drain, 1KW output power

The quasi-sine drain waveform of U3 is converted to a sine wave by the resonant action

of the tank network (Ct and Lt in Figure 7). The higher the Q of the resonant tank, the

more pure the sine wave is and the lesser the harmonic content in the RF output.

Figure 11 shows the output waveform at the 50Ω load after the output tank and

matching network. Figure 12 is a frequency domain measurement of the PRF-1150

harmonic content. The output power is 1KW (60 dBm) and note the second and all

higher harmonics are greater than 30 dB below the fundamental signal (≤ -30dBc).

Further filtering can easily be added in the output-matching network if additional

harmonic suppression is required.