Micro coaxial cable

1. A micro coaxial cable, comprising:

an inner conductor;

an insulation layer having foaming cells and formed to surround the inner conductor;

an over-foaming preventing layer formed to surround the insulation layer for the purpose of uniform forming of the foaming cells;

a metal shield layer formed to surround the over-foaming preventing layer; and

a protective coating layer formed to surround the metal shield layer,

wherein the over-foaming preventing layer has a lower melt temperature than the insulation layer,

wherein the over-foaming preventing layer is made of one or more polymer resins selected from the group consisting of polyethylene, polypropylene and polyethylene terephthalate,

wherein the insulation layer and the over-foaming preventing layer are formed using co-extrusion or tandem extrusion, and

wherein the micro coaxial cable has a diameter of 1 mm or less.

2. The micro coaxial cable according to claim 1 ,

wherein the insulation layer has a thickness of 0.03 to 0.09 mm.

3. The micro coaxial cable according to claim 1 ,

wherein the foaming cells provided in the insulation layer have a size of 0.02 to 0.07 mm.

4. The micro coaxial cable according to claim 1 ,

wherein the over-foaming preventing layer has a thickness of 0.01 to 0.04 mm.

5. The micro coaxial cable according to claim 1 ,

wherein the over-foaming preventing layer has a smaller thickness than the insulation layer.

6. The micro coaxial cable according to claim 1 ,

wherein the insulation layer is made of fluoric resin.

7. The micro coaxial cable according to claim 6 ,

wherein the fluoric resin is PFA (PerFluoroAlkoxy).