Hughes Aircraft Company

Richard V Basil, Jr

Juri G Leetmaa

James K Shimizu

Thomas Hudspeth

Harmon H Keeling

Donald G Swartz

Leons Ondrups

Meredith K Eick

A dielectrically loaded waveguide switch is disclosed which provides high power handling capability, small size and low weight. The invention includes first and second dielectrically loaded waveguides selectively connected by a switch. In a specific embodiment of the invention, the switch includes a third dielectrically loaded waveguide mounted for communication with said first and second waveguides upon switch actuation.

Dielectrically loaded waveguide switch

A low noise coaxial microwave window of particular utility in hermetic and high power applications, having a metallic center conductor, a metallic outer support, and a ceramic support brazed between the two conductors. The brazed joints are specially prepared to have a series of layers and sublayers extending from the ceramic to the metal, as follows: ceramic, cermet, cermet-nickel alloy, copper-nickel alloy, copper, braze metal, and metallic piece. The nickel content of the cermet-nickel and copper-nickel alloys is limited so that the alloys are non-magnetic. The nickel-containing alloys assist in bonding the copper layer to the cermet in a reliable, reproducible fashion, but control of the nickel content avoids microwave intermodulation effects. Where the window separates a vacuum from another medium, the surface of the support contacting the vacuum is formed from at least two noncoplanar segments to eliminate the possibility of multipacting. The same techniques are used in waveguide microwave windows.

Microwave window

In a microwave resonator, a variable cavity-wall segmentation along the location of a propagational current null is employed for thermal-compensation purposes by utilizing it in conjunction with supplemental mechanisms which operate to counteract thermally-induced variations in the resonator's characteristic geometry. Because dimensional variations at a current null will have minimum impact on resonator coupling parameters, a variably-configured current-null segmentation serves in a minimal-impact fashion to absorb those thermally-induced dimensional variations which occur transverse to the null. Of the three specific mechanisms disclosed for variational counteraction in the typical context of a resonator having both longitudinal and transverse extent with respect to a propagational axis, the first is a thermally-invariant assembly which provides thermal stabilization by inhibiting variations in the resonator's characteristic longitudinal extent. The second is a thermally-responsive structure configured to provide thermal compensation by affirmatively introducing longitudinal variations which are inversely proportional to otherwise-uncompensated transverse variations. The third mechanism, which may be employed in conjunction with either of the other two and which may take the form of thermally-invariant inserts configured as part of the resonant cavity's longitudinal walls, provides a further degree of thermal stabilization by inhibiting thermally-induced variations in the resonator's characteristic transverse dimensions.

Thermally-compensated microwave resonator utilizing current-null

A hybrid coupler is of the type known as a transverse electromagnetic mode, coupled transmission line coupler. The hybrid coupler is formed within a plate of metal by milling out channels of square cross-sections therein. The walls of the channels serve as outer conductors of coaxial lines, there being inner conductors of square cross-section positioned within the channel. A diagonally disposed window crosses the intersection of the ports and includes a separator. The central conductors of the respective coaxial lines are joined by diagonally disposed segments of inner conductor such that each pair of coaxial lines is so joined. Each pair of lines provides a pair of ports. The line segments are spaced apart by a spring-loaded separator for rigidly maintaining a coupling distance.

Square conductor coaxial coupler

Thermal compensation for frequency control of microwave resonators through utilization of bimetallic boundary motion type phenomena is described, the resonator being rectangular and preferably having composite broad walls of integral layers, one of which having a relatively lower thermal expansion coefficient than another of the layers and each having an initial deformation in a stabilized curvature condition to render these walls frequency sensitive.

Thermally compensated microwave resonator

A microwave resonator operating in the TE.sub.11 circular mode with a pair of iris plates defining the resonator, each iris including an elliptical aperture centrally disposed therein, the resonator having a rotary joint midway between the irises at the location of a current null so that the two half portions of the resonator may be rotated with respect to each other in order to provide a desired relative iris axis alignment for an infinitely variable coupling value between a minimum value determined by the minor axis dimension of the elliptical apertures and a maximum value determined by the major axis dimension thereof.

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Chatsworth, CA, United States of America

Richard V Basil, Jr