A 45-degree linearly polarized microstrip antenna array with reflection-canceling unit is proposed at W band.The single-row series-fed antenna array with sidelobe suppression of 25dB is designed by the Taylor-weighted

combined with reflection-canceling unit.Meanwhile the cross polarization is improved in the main lobe by adding the rectangular welt groove.The power divider with first order and ten ways replaces quarter wavelength transmission lines with the T-shaped structure junction

which achieves the power division ratio of 4.5 times.The simulation and measure results show that the antenna works from 75.7GHz to 77.6GHz by arraying.The horizontal and vertical azimuth for 3dB beam width can cover from-5 degrees to 5 degrees

where the cross polarization ratio is all higer 18dB.The gain of the antenna is 24dB and the sidelobe suppression is up to 20dB.The antenna can be used in the vehicle anti-collision radar and further improve whose anti-jamming capability.