Broadband microwave power amplifiers are one of the most important military and communication systems. Power and high efficiency, broadband, high linearity characteristics, low noise and long life are the most important issues in the design of amplifiers. Solid state devices and vacuum tubes are limitations to provide this feature. By using spatial power combining can overcome this limitation. Spatial combination unlike the circuit usual combining which limits efficiency, bandwidth, and heat transfer is a coherent method for combining multiple pieces of solid state using free space within a waveguide structure. In the first chapter of this project, the microwave and millimeter wave technology and applications in the areas of commercial and military are presented and then the characteristics of solid state devices and vacuum tubes and areas working they considered and finally, various methods of power combining, and its characteristics were studied. In the second chapter, definitions and parameters are used to evaluate the combiners will be discussed, and then in chapter three first, we do an analysis about the Power combiners, and the different designs of waveguide microwave power combiners in the frequency bands of X will analysis. And after that the processes of combiner construction in terms of bandwidth are investigated. Finally, in chapter four, we summarized and concluded. Keywords: Spatial power combiner, Broadband, power combiner, radial and rectangular waveguide