A blank for forming a collapsible field director structure comprises nonconductive material sheet having at least three panels thereon, one panel being a master panel and the other two panels being slave panels. Each panel is substantially rectangular in shape and has elongated upper and lower edges and two relatively shorter side edges. Each panel is connected to at least one adjacent panel along an elongated edge. A patch of adhesive is disposed on: the first surface of a first one of the panels; and another patch of adhesive is disposed on: the first surface on one of the other panels; or the second surface of said first one of the panels. The slave panels are each foldable along an elongated edge so that a surface of each slave panel is brought into confronting facial adjacency to and adhered against a surface of the master panel.