Microwave field director structure having vanes covered with a conductive sheath

摘要

A reusable self-supporting field director useful for heating an article in a microwave oven is characterized by a plurality of vanes, each vane extending radially outwardly from a central axis and being angularly adjacent to two other vanes. The vanes are attached to each other at their inner ends. Each vane has a substrate formed from an electrically non-conductive material, and an electrically conductive sheath encasing the substrate so that a portion of the first and second major surfaces are covered by an electrically conductive material. The sheath is arranged on the substrate in a laterally symmetric fashion so that thermal expansion effects due to heating are equalized across the thickness of each vane.