Abstract: A tray useful for the microwave cooking of prepared foodstuffs, particularly frozen foodstuffs, for consumption is structured to provide a more uniform heating of the foodstuff than has heretofore been possible. The tray comprises an outer layer formed of paperboard or molded plastic to which is laminated an inner polymeric film layer. A layer of microwave-reflective material, usually aluminum foil, is positioned between the outer and inner layers in the location of the peripheral wall of the tray and in a pattern in a portion of the bottom wall.

Abstract: A microwave energy intensifier is described comprising an array of dots of electroconductive material of microwave-reflecting thickness, particularly aluminum of foil thickness, supported on a dielectric substrate, particularly a flexible polymeric film substrate.

Abstract: In a popcorn package for microwave popping, the subsequent popping of popcorn by microwave energy is enhanced by the use of a layer of metallized ink printed on the bag of a popcorn package. The metallized ink contains powdered aluminum and is of a commercial grade but diluted to provide an opacity level of light transmission in the range of 47% to 10%, such layer lying below the charge of popcorn and shortening during popping. The material of the bag comprises a pair of plies with the layer of metallized ink being printed to one of the plies and disposed between the plies of the bag.

Abstract: A piece of microwave-active tape which is odor-free and physiologically inert can be adhered to a food package and remains strongly adhered during cooking at temperatures of at least 200.degree. C. The tape has layers of microwave-active material and a pressure-sensitive adhesive which is a polymeric .alpha.-olefin that has been cured to afford a "Peel Value" of at least 5 N/dm and a "Shrink Back" at 220.degree. C. of less than 5%. The tape can have a flexible backing such as a low-adhesion carrier web which can be stripped off from a piece of the tape that has been applied to a microwave food package, or when the backing is heat-resistant, it can be left in place.

Abstract: A utensil for microwave cooking for eggs includes a container body of microwave transmisable material having a side wall merging with a base. The base includes a centrally located yolk retention portion and forms with the side wall a white retention portion. The form and relative disposition of the base and side wall are such that substantially all microwave radiation first entering the yolk after passage through the egg white will previously have passed through the side wall or base.

Abstract: A microwave heating element is described which permits a more uniform microwave cooking of a foodstuff to be achieved. The element comprises a layer of electroconductive material having circular openings formed therethrough and arranged in an array that generates thermal energy when exposed to microwave energy and adjacent a foodstuff. An antenna is provided in at least some of the openings to guide microwave energy to and through the openings. The electroconductive material layer usually is adhered to a paperboard layer with an overlying polymeric film layer.