Inspired by the theory of leaky wave antenna, a broadband and wide-angle frequency scanning antenna is proposed in this paper. My goal is to trade a narrow frequency band for a wide-angle beam scanning. Since the dispersion of spoof surface plasmon polariton (SSPP) mode slow-wave possesses larger gradient than that of the waves in the air, the metallic corrugated line (MCL) is adopted for energy transmission. To convert confined slow-wave into radiated fast-wave, a number of metallic patches are alternatively and periodically loaded besides the MCL and fed by electrically coupling. Owing to the frequency-dispersive phase difference between two patches, the resultant radiations are capable of beam scanning. As an example, the fabricated prototype operates in a relative bandwidth of 19.5 % (from 7.4 GHz to 9.0 GHz). Both the simulated and measured results have verified that the main beam of leaky-wave radiation can continuously scan from the backward direction to the forward direction with a scanning angular domain of 56° and an average gain level of 12.0 dB.