The invention provides a high-isolation triple-coaxial leaky
coaxial cable. The isolating performance of the cable is excellent and the original main
radiation signal is enhanced, so that the same-row wiring distance between leaky cables can be shortened substantially; and thus leaky cables can be distributed in a limited space area, so that the area meets the
signal coverage requirement. The provided leaky
coaxial cable comprises an inner conductor, an inner
insulation layer, an inner-layer outer conductor, an outer
insulation layer and a sheath successively from the center to the outer ring surface and is characterized in that a gap notch is formed in the inner-layer outer conductor and the gap
radian alpha formed by the gap notch is 0 to 0.5 pi, wherein the gap
radian alpha decreases with increasing of an optimal
operating frequency; and an outer-layer outer conductor is arranged at an outer ring position corresponding to the gap notch, wherein the outer-layer outer conductor is a piece of arc
metal. The corresponding center axes of the outer-layer outer conductor, the inner-layer outer conductor, and the inner conductor are overlapped. The outer-layer outer conductor is arranged at the outer side of the inner-layer outer conductor; and the arc
radian beta of the outer-layer outer conductor is larger than the gap radian alpha.