RF Electronics Chapter 9: Impedance Matching of Power Amplifiers Page 330
2022, C. J. Kikkert, James Cook University, ISBN 978-0-6486803-9-0.
placing a resistor at the input terminal of the FET will make the amplifier stable. Reducing
the input coupling capacitor will improve the stability at 165 MHz. Placing optimisation
constraints to ensure that the amplifier's gain (DB(|S2,1|)) is between 21dB and 23 dB
enhances the stability and aims for a flat gain. The matching networks are then optimised
again, to achieve a suitable amplifier performance. Figure 9.41 shows the amplifier's
performance. Figure 9.42 shows the resulting circuit values, including the final element
modification constants. The amplifier input match (blue curves) has been improved
compared to figure 9.39. The stability factors show that the amplifier is unconditionally
stable and the amplifier's gain is just over 21 dB from 300 MHz to 400 MHz.
Figure 9.42. Final amplifier matching networks.
Figure 9.43. Final broadband amplifier stability circles.
RF Electronics: Design and Simulation
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