A concept of providing wireless power supply with microwave beam for pilotless aircrafts is introduced. The article presents justification of the choice of focusing type electromagnetic radiation (EMR) based on the requirements to the wireless power transmission (WPT) system. The features of the EMR focusing on receiving-rectifying antenna (rectenna) installed on movable objects are considered. With this in mind the calculated ratio for focused fields analysis has been modified and the mathematic modeling of the field at the rectenna aperture has been conducted.