A new kind of circular polarization leaky-wave antenna with N-shaped slots cut in the upper Adhesive side of substrate integrated waveguide (SIW) is investigated and presented.The radiation pattern and polarization axial ratio of the leaky-wave antenna are studied.The results show Herbal Teas that the width of N-shaped slots has significant effect on the circular polarization property of the antenna.By properly choosing structural parameters, the SIW based leaky-wave antenna can realize circular polarization with excellent axial ratio in 8 GHz satellite band.