Abstract:
This project deals with the design and implementation of a 5W class AB power
amplifier at a frequency of 1.08 GHz. The power amplifier was designed to achieve
a gain of 37 dB and PAE greater than 40%. The design was completed in two stages
to compensate for the high gain requirement. The first stage deals with the design
and fabrication of driver amplifier. The device used was ATF-34143 by Avago.
Driver amplifier was designed to achieve a gain of approximately 17 dB and
input/output return loss smaller than -10 dB. The amplifier was designed using
conjugate matching approach. The simulated gain for driver amplifier was
17.138 dB. The design was then fabricated and a gain of 17.39 dB was achieved.
The circuit was fabricated using microstrip line and the substrate used was Rogers 4350. The second part deals with the design and hardware implementation of class
AB power output stage. The device used was AFT27S010N by NXP. The amplifier
was designed for an input power of 17 dBm and the expected output power was
37dBm. The expected gain was 20 dB and PAE greater than 40%. The design was
based on load-pull data and harmonic simulations. The simulated gain was
20.058 dB and power added efficiency of 56 % was achieved. This design was
fabricated using similar circuit topologies and substrate as driver amplifier. For an
input power of 17 dBm the measured output power was 36.7 dBm. Gain of 19.7 dB
was achieved from the power amplifier circuit with power added efficiency of
38.9 %.
