Abstract:
Power amplifiers are considered as one of the most important components of any
communication system. The design, layout and testing of power amplifier are considered
as the most challenging task in the wireless communication systems front-end as it is the
high consumer of power. With the rapid technological development, multiband
transmitters and receivers are required for the systems, that involves highly efficient and
linear power amplifiers. Moreover, communication systems, especially radar systems
front end require frequency agile PAs, which are further categorized as broadband,
multiband and reconfigurable types. Output power and efficiency are key characteristics
of power amplifiers which most of the time are subject to trade-offs. Therefore, with
multiband power amplifiers, getting high power and good efficiency simultaneously is
considerably more difficult.
The main objective of this thesis is to design a dual band reconfigurable power amplifier
for radar front-end for L and S Band applications. For this purpose, a T shape matching
network consists of distributed components and is designed to achieve reconfigurability
in both bands. Radial stubs are used to decrease the size of the circuit and to ensure the
isolation at both frequencies. Large signal analysis shows that PA achieves 5 watts at
both bands along with drain efficiency of 45-50%. The large signal gain is around 38 dB,
and the small signal gain is around 50 dB and 39 dB at 1.087 GHz and 2.8GHz
respectively. The input and output return loss are greater than -10 dB along with the 40
dBm 3-dB gain compression output power level (OIP3).
