The book particularly deals with the analysis of a uniform planar antenna array consisting of the open ends of waveguides laid side by side. The boundary value problem for such arrays has been strictly formulated and presented in the form of an integral equation. These integral equations can be solved numerically (and in some cases analytically) with a high accuracy. Using the solution, you can calculate all essential parameters of an antenna array: radiation and reflection characteristics (including polarization characteristics) and also the coefficients of mutual coupling. The obtained relations and calculation methods can be applied to vibrator radiators and other types of antenna elements. But since vibrator antenna arrays are studied well enough, they are not considered in detail in this book. Besides, the issues related to the synthesis of radiation patterns that are extensively discussed in the literature are also omitted.