Abstract: A microwave window is made as a flat layer of dielectric material having opposite first and second surfaces. Between these surfaces, the window is formed with a plurality of parallel coolant channels which, in cross-section, have racetrack configurations with flat sides and curved ends. The channels are distanced from each other in the window to establish parallel plate waveguides between the flat sides of adjacent channels. A plurality of cylindrical lenses are formed on the first surface of the dielectric layer to focus incident microwaves into convergence in a respective waveguide. Additionally, a plurality of cylindrical lenses are formed on the second surface of the dielectric layer to refocus microwaves emerging from the parallel plate waveguides back into a substantially parallel relationship as the microwaves radiate from the window.

Abstract: A distributed microwave window (12) couples microwave power in the HE11 mode between a first large diameter waveguide (32) and a second large diameter waveguide (34), while providing a physical barrier between the two waveguides, without the need for any transitions to other shapes or diameters. The window comprises a stack of alternating dielectric (14) and hollow metallic (16) strips, brazed together to form a vacuum barrier. The vacuum barrier is either transverse to or tilted with respect to the waveguide axis. The strips are oriented to be perpendicular to the transverse electric field of the incident microwave power. The metallic strips are tapered on both sides of the vacuum barrier, which taper serves to funnel the incident microwave power through the dielectric strips (14). A suitable coolant flows through a coolant channel (18) that passes through the metallic strips (16).