Abstract: A metal rod rack shelf for a microwave oven wherein extension support rods are substantially prevented from being excited with high electric currents. The rack is embodied with quarter wavelength choking structures in the regions where the extension support rods connect to the rack mainframe. Accordingly, the effective short circuits in those regions are transformed to open circuits at a distance of one-quarter wavelength along the support rods. As a result, the support rods do not rise to high temperatures or radiate intense microwave fields that could cause melting of or arcing to microwave transparent brackets which mount to walls of the oven cavity and engage the rods.

Abstract: Antenna for use with food product in a microwave oven, where one or more antennas are positioned into the food product for efficient and distributed heating of food product. The antenna includes a coaxial assembly of an inner conductor and an outer conductor with dielectric therebetween. A load end, configured as a probe, positions into the food product. A source end antenna element structure delivers power to the load end and subsequently to the food product. The structure at the source end may include a probe center conductor as well as gain antenna structures. The outer conductor may likewise be configured including ground plane disc, a folded-over coaxial outer conductor or the like.

Abstract: A windowed door assembly for a combination microwave and hot air oven having a choke-coupling type seal formed around the periphery of the window opening to suppress the leakage of microwave energy from the area between the main body of the door and the window portion of the door. The window portion is removably connected to the main body of the door in a region of relatively high capacitive impedance to reduce the importance of the mechanical connection in suppressing the leakage of microwave energy from the oven.

Abstract: A microwave oven having a door with a peripheral microwave seal structure which is fabricated from one or more die formed aluminum parts and solid dielectric inserts to form a resonant transmission line structure with peripheral oven wall portions, with transmission of microwave energy in the seal around the periphery of the door prevented by impedance discontinuities, and leakage of microwave energy through the seal is prevented by impedance mismatch or resonant choke action of the seal structure, and the size of a notch in a solid dielectric insert in a quarter wavelength shorted branch line of the seal is selected for different production runs of the oven to compensate for dimensional changes in different die stamped metal parts or assembled door structures due to assembly jig changes, stamping die wear or assembly procedures.