In order to solve the problem of limited bandwidth and large overall size of leaky-wave antenna, a new wide-band leaky-wave antenna is proposed in this paper. The antenna is composed of surface plasmon polaritons transmission lines and asymmetric circular patches. It works at 7 ~ 15 GHz (relative bandwidth of 72.73%), enabling continuous beam scanning from backward to forward with a beam scanning angle of 69 ° and a stable high radiation gain. The maximum gain of the antenna in simulation reaches 13.1 dBi and the measured gain variation is only 1.64 dB. The test results are good agree with the simulation results. The proposed leaky-wave antenna has the advantages of simple structure, stable performance and easy fabrication. Furthermore, the overall size of the antenna is comparatively small, which makes it conducive to the conformable integration in wireless communication systems.