Helical wave guide

A helical wave-guide having a conductor wound in a helix, and an electrically conductive screen surrounding said conductor comprising:

• a wire coated with a thermoplastic insulator, adjacent turns of the helix being welded together by surface melting of the thermoplastic insulator, the insulation between adjacent turns degenerating predetermined modes and reducing electromagnetic transmission losses, said surface melting of the thermoplastic insulator providing mechanical bonding and electrical insulation, said thermoplastic insulator including a substantially thin layer of polar material of the grafted polyethylene type coated on the electrically conductive wire having a thermoplastic insulating coating selected from the group of polyolefines consisting of polyethylene, Teflon or polypropylene, said electrically conductive screen being formed by a metallic tube coated at its ends on its inside wall with a substantially thin layer of a heat sealing material for ensuring fixing of the helix inside the screen.