Design of fast-scanning millimeter-wave monopulse antenna

8 mm fast-scanning monopulse antenna has been accomplished by using polarized twisted Cassegrain antenna, 4-horn feed and waveguide hybrid-ring sum-and-difference network. Design, tolerance analysis and simulation of the antenna are presented. Due to performing detailed tolerance analysis, the experimental results of prototype without any adjusting almost perfectly agree with design values. It is indicated that the design methods and tolerance analysis are suitable to engineering application.