US Patent 4,346,139, granted 24 August 1982 to Osawa, Nishimura and Toyooka of Sumitomo Electric Industries, for a weather-proof, high-strength membrane material for radomes. The membrane is a layered laminate: polyvinyl fluoride film, adhesive, sprayed urethane, a triaxially woven polyaramide (Kevlar-type) fabric with axes at 60 degrees, and a second sprayed urethane layer. The triaxial weave is claimed to resist creasing on triangular frames and to keep radio-wave permeability. The scan includes a web-database printout and the original patent pages with four figures, 13 claims and a description.