Abstract: A domed ceiling structure for attachment to an elevated support. The ceiling structure comprises a peripheral frame member which is attachable to the support frame, and a plurality of arcuate support members, each of which has first and second ends, an upper surface, and an under surface. The first ends of the support members are attached to the frame member in a manner wherein the second ends extend to a common area and the under surfaces collectively define a dome shaped support surface to which a layer of finishing material may be applied.

Abstract: A device for forming an arcuate ceiling structure which is positionable between first and second opposed rows of vertical wall studs having at least one horizontal header extending therebetween. The device comprises a first ledger attached to the first row of wall studs and the second ledger attached to the second row of wall studs. At least one arcuate member is provided which has first and second longitudinal ends, an arcuate upper surface and an arcuate undersurface. The length between the first and second ends is such that when the arcuate member is positioned between the first and second ledgers, the first end will abut the first ledger, the second end will abut the second ledger, a portion of the upper surface will abut a header, and the undersurface will form an arcuate support surface to which a sheet of finishing material may be applied.

Abstract: A device for forming an arcuate ceiling structure which is positionable between first and second opposed rows of vertical wall studs having at least one horizontal header extending therebetween. The device comprises a first ledger attached to the first row of wall studs and the second ledger attached to the second row of wall studs. At least one arcuate member is provided which has first and second longitudinal ends, an arcuate upper surface and an arcuate undersurface. The length between the first and second ends is such that when the arcuate member is positioned between the first and second ledgers, the first end will abut the first ledger, the second end will abut the second ledger, a portion of the upper surface will abut a header, and the undersurface will form an arcuate support surface to which a sheet of finishing material may be applied.

Abstract: An arcuate window frame mounting structure is disclosed comprising an arcuate member sized and configured to be inserted within an existing wall structure, such that the outer edge of the member will interface with the back side of an exteriorally mounted arcuate window frame while the inner edge of the member will be flush with the inner edges or surfaces of the adjacent wall studs. In addition, methods of forming the arcuate window frame mounting structure are disclosed.

Abstract: The invention relates to a resonant cavity device such as a magnetron oscillator which is tunable by means of a tuning plunger associated with sealing bellows. A volume defined at least in part by the bellows and producing a range of spurious responses as the tuning plunger is moved is isolated from the resonant cavity or cavities of the device by an isolating choke. The choke may take the form of an annulus having a major radius of 1/4 .lambda. (where .lambda. is the mid-frequency of the tuning range) attached either to the plunger or to the main body of the device and between the bellows and the resonant cavity or cavities.

Abstract: In a vane type magnetron oscillator a resonant co-axial transmission line breaks through the wall of the anode block to couple to two adjacent cavities on either side of a vane. Positioned at a point at which a high radio frequency voltage appears in operation approximately an odd multiple of a quarter wavelength (preferably 3.lambda./4) from the end of the transmission line adjacent the cavities is a multipactor discharge arrangement. This latter consists of two co-axial cylinders one connected to the inner conductor and the other to the outer conductor of said transmission line. The transmission line extends beyond the multipactor discharge arrangement to a total length approximately half wavelength or a multiple thereof and is short circuited at its end.

Abstract: This invention relates to a co-axial magnetron in which a separate resonator incorporating a multipactor discharge arrangement is used to tune the operating frequency of the magnetron. The separate resonator is symmetrically coupled via couplers into the main resonator cavity of the magnetron. More than one separate resonant can be provided, in which case they are symmetrically coupled into the main resonant cavity to achieve correct tuning.