Passive intermodulation products (PIM) free tape

An electrically non-conductive and RF shielding tape for seaming together and for repairing holes or damaged portions of RF shielding thermal blankets of the kind used for covering metal components of communications spacecraft, said tape having a construction for preventing RF energy from penetrating the seams, holes or damaged portions of the RF shielding thermal blankets which, in the presence of certain metal-to-metal junctions or shapes, can produce undesirable passive intermodulation products (PIM), said tape comprising:

• a) a metallic barrier strip which provides a barrier to RF energy;
• said metallic barrier strip comprising a strip of metal foil having an outboard surface, an inboard surface and opposed side edges spaced a distance apart to define a strip width;
• b) PIM shielding structure which encapsulates the outboard surface, the inboard surface and the opposed side edges of the strip of metal foil for electrically isolating and insulating the metal surfaces of the strip of metal foil to prevent the formation of PIM producing metal-to-metal junctions as the tape structure is applied to metal bodies or wound onto itself;
• said PIM shielding structure comprising,
• i) a strip of plastic material forming an outer layer of the tape, said strip of plastic material having an outboard surface, an inboard surface and opposed side edges spaced a distance apart to define a strip width, said strip width of said strip of plastic material being wider than said strip width of said strip of metal foil and providing side margins extending outwardly beyond the side edges of the metallic barrier strip,
• ii. an adhesive adhering said outboard surface of said strip of metal foil to said inboard surface of said strip of said plastic material such that said side edges of said strip of metal foil are located inwardly of said side edges of said strip of plastic material thereby leaving a pair of exposed side margins along said inboard surface of said plastic material;
• and
• iii. a layer of adhesive gum material forming a bottom layer of the tape and disposed covering and adhered to both said inboard surface of said strip of metal foil and said exposed side margins of said inboard surface of said plastic material.