RF Electronics Chapter 9: Impedance Matching of Power Amplifiers Page 333
2022, C. J. Kikkert, James Cook University, ISBN 978-0-6486803-9-0.
for both the Class AB push-pull devices, resulting in low even harmonic levels. The
AWRDE nonlinear library and its installation instruction for their devices is available by
application from Wolfspeed [10]. For this example, a wideband amplifier at 1 GHz with
a good PAE and stability for an input and output VSWR of better than 6:1 is required.
The basic AWR DE circuit schematic for the amplifier is shown in figure 9.46.
Figure 9.47. Tapped transformer Input Matching.
Figure 9.48. Tuned parameters for the power amplifier with transformer matching.
The input matching circuit is shown in figure 9.47. A similar network is used for the
output matching. The input network has a series resistance Rin and reactance Xin. The
output network only has a series reactance Xout. Rin assists in providing stability. Rin,
Xin, Xout, the turns-ratios Ngt for the input and Ndt for the output, and the bias voltage
are all tuned to obtain a good PAE, bandwidth, stability and harmonic levels. Figure 9.48
show the resulting values. The resulting gain, PAE, output power at the fundamental and
harmonics, versus input power is shown in figure 9.49. At a 1 dB compression,
corresponding to an input of 26.81 dBm, the output power is 84.42W, the third harmonic
output is 0.8W and the PAE is 44.68%.
Figure 9.49. Output performance of the transformer matched power amplifier.
RF Electronics: Design and Simulation
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