Abstract: A waveguide assembly for operation over a range of temperatures includes a waveguide body and a plurality of restraining strips coupled to the waveguide body. The waveguide body includes a pre-curved narrow sidewall of material having a first coefficient of thermal expansion (CTE). The restraining strips are coupled to the waveguide body at first and second lateral points on either side of the pre-curved narrow sidewall laterally and are spaced apart along the length of the waveguide body, and are made from a material having a second CTE much less than the first CTE.

Abstract: A waveguide assembly for operation over a range of temperatures includes a waveguide body and a plurality of restraining strips coupled to the waveguide body. The waveguide body includes a pre-curved narrow sidewall of material having a first coefficient of thermal expansion (CTE). The restraining strips are coupled to the waveguide body at first and second lateral points on either side of the pre-curved narrow sidewall laterally and are spaced apart along the length of the waveguide body, and are made from a material having a second CTE much less than the first CTE.

Abstract: A device for changing the operating frequency of a microwave filter is mounted in a wall of a cavity of the filter. The device has a bellows that is located inside the cavity. The bellows contains an elongated member that extends outside the cavity to an actuator. The actuator can be temperature dependent and moves the elongated member either further into or further out of the cavity as desired. An interior end of the elongated member can be connected to the bellows or it can simply be in contact with the bellows without being connected. When the elongated member is in contact with the bellows and is not connected, when the elongated member moves outward, the bellows will return to a rest position due to its inherent spring. The bellows is sealed from an interior of the cavity. Filters using the device have one device located primarily for each mode in each cavity of the filter.

Abstract: C-, T- and S-switches have a connector or reed in each conducting path. The connector or reed contains a support for a permanent magnet. All of the magnets of the connectors have the same polarity. The connectors, supports and permanent reed magnets in the supports are contained within an RF cavity housing, which can be completely sealed from an actuator or, alternatively, the housing can be open to the actuator. The actuator has a circular shape and contains permanent magnets that correspond in their configuration to the reed magnets of the housing. At least two magnets of the actuator have different polarities. The actuator can be rotated by a motor to two or more positions. In one position, one or more of the reed magnets are attracted and one or more of the reed magnets are repelled. The switch is designed so that when a reed magnet is attracted, the conducting path in which the connector is located is interrupted and when a reed magnet is repelled, the conducting path is connected.