The invention discloses an antenna structure and a design method thereof. The antenna structure comprises a
linear array radiation unit and a substrate integrated
waveguide feeding network, wherein an output end of the substrate integrated
waveguide feeding network is connected with an input end of the
radiation unit, a substrate integrated
waveguide power
distributor is of a structure for dividing one path into six paths, the structure for dividing one path into six paths comprises an input passage and six output passages, a
metal hole is formed in an inlet of each output passage and is used for adjusting power and phase of the output passage, and an outlet of each output passage is connected with the
radiation unit. By the antenna structure, an intermediate-long combined antenna based on a compact feeding network is achieved, and the size of the feeding network is greatly reduced. By the antenna, the demands of intermediate-distance test and long-distance test of a
radar can be simultaneously satisfied, a
millimeter-wave switch is not needed to switch among various antennas, and meanwhile, the antenna structure has the advantages of compactness, low cost, low profile, small size and the like.