The invention relates to a leaky coaxial antenna (10) comprising an inner conductor (1), a dielectric (2) around the inner conductor (1), and a first shield conductor (4) disposed around the dielectric (2), the first shield conductor having openings (41) distributed in longitudinal direction of the inner conductor (1) and being adapted in that electromagnetic energy passes through the openings (41). A second shield conductor (5) is disposed around or underneath the first shield conductor (4), the second shield conductor (5) being adapted to cover or mask at least a number of the openings (41) of the first shield conductor in a shielded section (S1-S12). The second shield conductor (5) is arranged discontinuously In the longitudinal direction of the antenna (10) defining uncovered or unmasked portions (AS1-AS12) of the first shield conductor (4) in the longitudinal direction of the antenna which are adapted in that electromagnetic energy passes through the uncovered portions (AS1-AS12). Thus, the present invention suggests a two-layer shield for improving the properties of a leaky coaxial antenna with respect to e.g. aerospace applications.