Composite microwave window and waveguide transform

Claim 1

In a high frequency gas tight wave permeable window assembly dimensioned for passing wave energy therethrough over a certain passband of frequencies, a first tubular waveguide member having a first height, second and third tubular waveguide members having waveguide heights substantially less than the height of said first guide, centrally apertured end walls of said first waveguide member forming abrupt waveguide transitions for connecting said second and third waveguide members to said first waveguide member substantially at the eNds of the said first waveguide member, a gas tight wave permeable window member disposed transversely of and within said first waveguide member, the thickness of said wave permeable window member being substantially less than 1/2 of an electrical wavelength at the center frequency of the passband of the wave permeable window assembly, and the length of said first waveguide member plus the fringing field regions extending into the adjacent second and third waveguides at said abrupt transitions, and with said wave permeable window in place, being approximately n/2 electrical wavelengths long at the center frequency of the certain passband of said window assembly, where n can have any odd integer value, said second waveguide member having a substantially uniform lower height than said third waveguide member, and said wave permeable window member being substantially displaced from the midlength position in said first waveguide toward the end thereof connecting to said second waveguide, whereby a relatively broadband composite microwave window and waveguide transformer is obtained.