In standard antenna array, high grating-lobe caused by large space between elements would degrade antenna performance, and in this letter, we propose a corrugated two-slots array with a space larger than a wavelength in the E-plane, which can realize high radiation performance. A corrugated structure is loaded between slot elements as the secondary radiation source, and this slot source is based on slot dipole resonance mode to keep a low-profile. Simulated and measured results both show high grating-lobe level drastically suppressed to less than 10 dB with the introduction of the corrugated grooves, compared to the case of flat two-slot array without grooves. Additionally, the antenna gain is significantly increased by about 9 dB, and half-power beamwidth (HPBW) in both E-and H-plane are narrowed as well. This letter is also considered as a reply to Appl. Phys. Lett., vol. 93, pp. 156101, Oct. 2008.