A power amplifier design has to meet the system requirements for high gain, high efficiency and desired output power while the device and process technology of choice plays a crucial role in realizing the performance of the power amplifier. Power amplifiers are a key component for the digital cellular Phones with ever increasing linearity and efficiency requirements. These amplifiers consume much of the total battery DC power and occupy significant area. DC power consumption has to be reduced for High-efficiency power amplifiers. High-efficiency operation is required as an important factor for reducing the prime power and cooling requirements for advanced microwave and millimeter wave radar, communication and electronic warfare systems.