As an important branch of modern radar, passive radar is now taken seriously by some countries, and ultra wideband antenna & feed system is a key part of passive radar. The paper mainly makes a preliminary analysis of the theory of Ultra wideband antenna & feed system and according to the different application of passive radar, makes a detailed study of wide beam Ultra wideband antenna feed system and pen beam Ultra wideband antenna & feed system respectively. It also carries on a series of simul...