In this paper, a new design strategy was proposed in order to enhance bandwidth and efficiency of power amplifier.The strategy presented in this paper is based on simultaneous usage of Doherty and distributed structures and a new wide band power divider in a power amplifier to benefit from their advantages simultaneously. To realize the introduced design strategy, a power amplifier was designed using TSMC CMOS 0.18um technology for operating in the Ka band, i.e. the frequency range of 26.5-40GHz. First, a power divider with a very wide bandwidth, i.e. 1-40GHz, was designed to cover the entire Ka band. After fabrication of the designed power divider and evaluation its operation in laboratory, it can be seen that simulation and measurement results are in good agreement. In the power amplifier, each of the two pathways was amplified by a cascaded multi-stage distributed power amplifier. The simulation results indicated that the gain of proposed power amplifier at the frequency of 26-35GHz was more than 30dB. The maximum Power Added Efficiency (PAE) of the designed power amplifier was 80%. The output P1dB of the introduced structure was 36dB, and the output power of power amplifier was 36dBm. Finally, the IP3 value of power amplifier was about 17dB.