A shielding structure for transmission lines comprises first and second comb-like structures defined in a first metallization layer on an integrated circuit, the teeth of each comb-like structure extending toward the other comb-like structure; a first plurality of electrically conducting vias extending upward from the first comb-like structure; a second plurality of electrically conducting vias extending upward from the second comb-like structure; first and second planar structures in a second metallization layer above the first metallization layer; a third plurality of electrically conducting vias extending downward from the first planar structure toward the first plurality of electrically conducting vias; and a fourth plurality of electrically conducting vias extending downward from the second planar structure toward the second plurality of electrically conducting vias. The comb-like structures, the planar structures and the first, second, third, and fourth electrically conducting vias are all at substantially the same potential, preferably ground.