GB1433505A - Microwave oven - Google Patents

Abstract

1433505 Microwave ovens SAGE LABORATORIES Inc 2 May 1973 [3 May 1972] 20791/73 Heading H5H A microwave oven enclosure 10, Fig. 1, 40, Fig. 4, is coupled to an end of an energy supplying rectangular waveguide 14, Fig. 1, 42, Fig. 4, by a matching coupling means 12, Fig. 1, 44, Fig. 4, that establishes primarily only the dominant TE10 mode in the enclosure when the dominant TE10 mode is excited in the waveguide. The waveguide opens into the enclosure in a rectangular opening. The matching coupling means may comprise: a quarter wavelength step transformer 12, Fig. 1; a sleeve surrounding the opening that may be rectangular, 44, Fig. 4, or circular 54, Fig. 5, or elliptical; a series of posts that may lie on a circular path 58, Fig. 6, or on a rectangle or an ellipse; an elongate conductive member extending from the waveguide opening that turn through a right angle towards an adjacent wall and either is attached thereto 66, Fig. 7, or spaced therefrom (80, Fig. 8, not shown). The elongate conductive member 66, Fig. 7, may comprise a strap, a bar or a series of bars or wire mesh. It may be attached to an edge of the opening or to a bar which is vertically adjustable across the opening (94, Fig. 9, not shown). The invention is stated to provide a greater concentration of energy in a central region of the enclosure.