The log periodic antenna was invented by [[DwightJohn Isbell|DwightDunlavy E.in Isbell]]1952 while working for the United States Air Force, Raymondbut DuHamelwas andnot variantscreditied bywith Paulit Mayesdue to it's "Secret" classification. <ref>https://www.stereophile.com/content/loudspeaker-designer-john-dunlavy-numbers-page-4</ref> The [[University of Illinois at Urbana–Champaign]] had patented the Isbell and Mayes-Carrel antennas and licensed the design as a package exclusively to JFD Electronics in New York. [[Channel Master]] and [[Blonder Tongue Labs]] ignored the patents and produced a wide range of antennas based on this design. Lawsuits regarding the antenna patent which the UI Foundation lost, evolved into the 1971 Blonder-Tongue Doctrine.<ref>{{Cite web|url=https://definitions.uslegal.com/b/blonder-tongue-doctrine/|title=Blonder–Tongue Doctrine Law and Legal Definition | USLegal, Inc.|website=definitions.uslegal.com}}</ref> This precedent governs patent litigation.{{Citation needed|date=July 2018}}
