In the thesis, the architectures of direct up-conversion and double up-conversion transmitter were discussed and a direct up-conversion module operating at 8.3GHz was developed. The practical design considerations of a high power amplifier such as the DC bias network, devices and PCBs heat dissipation and groundings, etc., are highlighted. To couple forward output power, instead of using a conventional coupler that has higher insertion loss and bigger physical dimension, a novel and simple X-band power divider was designed. Three high power (>8W) and high gain (>33dB) cascade power amplifier Engineering Models (EM) operating at 8.3GHz were designed and developed. Without significant redesign effort, a few methods on how to overcome cavity resonance of cascade amplifiers module were also presented. Besides, a novel approach on how to design S-band high power amplifier based on small signal S-parameters analysis and passive load pull were demonstrated. In addition, a novel technique was shown on how to design a linear power amplifier without performing sophisticated PA linearization.