Abstract: A linear array antenna with high power-handling capacity is designed in this article, which is feed through slots of rectangle wave-guide. A new cambered slot coupling structure is applied in the antenna, which radiation element is a small antenna, and one dimension beam scanning is realized by rotating the inner conductor of the helical line to adjust the phase of the radiation element. The theoretical design is accomplished according to the equivalent transmission theory, the simulation results indicate that: one 3200.00 mm long array antenna has the gain of 27.50 dB at the frequency of 8.40 GHz, and the axial ratio is 0.51 dB. The power-capacity is about 90 MW, and the efficiency of the antenna is 97.10%. The reflectance is below -24 dB, and the beam scanning is ±38°.