الفهرس 
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Abstract
The design of RF power amplifier in WSNs is influenced by many challenging factors that must be overcome for efficient communication to be achieved in WSNs. Some of these challenges and some design guidelines to be considered in the design process include; Energy consumption without losing accuracy, Communication range, Hardware constraints and Signal to Noise Ratio. Power amplifiers are typically the most power-hungry building blocks of RF transceivers. The design of PAs, especially for linear, low voltage operation, remains a difficult problem, still defying an elegant solution. In practice, PA design has involved a substantial amount of trial and error, this is one of the reasons why discrete or hybrid implementation of this circuits are favored. One of the main design goals of WSNs is to prolong the lifetime of the network and prevent connectivity degradation by employing high efficiency RF power amplifier techniques. This thesis tried to overcome some of the limitations and drawbacks of the existing RF power amplifiers designed for WSN. The enhanced RF power amplifier should extend the WSN lifetime and takes into account the tradeoff between data accuracy, and energy consumption. A class-E PA has been designed to operate in the Zigbee at 868MHz frequency range, the designed PA has been linearized using CFB. The simulation analysis gives a good start to achieve our goal in Cartesian feedback power amplifier design. Cartesian feedback (CFB) is also a classic solution, in which continuous analog feedback makes the PA output linearly follow the input. Despite the excellent energy efficiency of CFB for PA linearization and the natural robustness to variations in the PA model, simulation analysis can make predication of the actual PA performance. This thesis makes a good improvement in the linearity of
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class-E power amplifier. As the output spectrum of the PA has been improved by (22dB) after applying closed loop Cartesian feedback.
We can say that a good linearity is achieved, or in other words, we can say that linearization performances (22dB) ACPR is improved at 300 KHz offset, at 868MHz.IIP happened at (13.3 dBm) instead of (-11.9 dBm) with 25.2dB improvement and IIP3 happened at (21.9 dBm) instead of (7.5 dBm) with 14.4 dB improvement.