Microwave energy moderator

Abstract

A microwave moderator for partially attenuating and/or modifying microwave energy to achieve, for instance, more uniform cooking of comestible articles in microwave ovens. Packages, bags, and wraps are disclosed which comprise such microwave moderators and which enable microwave cooking of frozen foods at relatively high microwave oven power levels without requiring precooking, defrosting or oven power level changes. Such a moderator may comprise an array of alternately disposed or spaced areas of microwave reflective material, and complemental-shape, substantially microwave transparent zones. One species of such moderators is exemplified by a wrap which comprises a perforate sheet of microwave reflective material; for instance, aluminum foil. In embodiments comprising such a perforate sheet, the perforate sheet is provided with a plurality of generally uniformly spaced apertures which are sufficiently large with respect to the wavelength of the microwave energy that a substantial portion of such microwave energy directed at said moderator will pass therethrough. The moderator may also include a sheet of microwave transparent, moisture barrier material such as thermoplastic film which is selectively foraminous or perforated to control the passage of vapor (for venting) and liquids (for draining) through the moderator. A dynamic, temperature responsive microwave moderator is also disclosed which will change from being relatively transparent to microwave energy or having a predetermined degree of microwave energy transmissibility to being substantially less transparent or substantially opaque to microwave energy or to having a substantially diminished degree of microwave energy transmissibility when heated to or above a predetermined temperature.