Patent ID: 6897746

Claim:
A waveguide assembly for operation over a range of temperatures, said waveguide assembly comprising: (a) a waveguide body having an effective large dimension and a length, said waveguide body including at least one pre-curved narrow wall made from material having a first coefficient of thermal expansion; (b) a plurality of restraining strips extending across said pre-curved narrow wall and coupled to the waveguide body on either side of said pre-curved narrow sidewall at first and second lateral points, said restraining strips being spaced from each other and being provided along the length of said waveguide body and being made from a material having a second coefficient of thermal expansion substantially less than the first coefficient of thermal expansion; and (c) said plurality of restraining strips being used to maintain a substantially constant lateral distance between said first and second lateral points over the range of temperatures such that as the length of the waveguide varies with temperature, the degree of curvature of said at least one pre-curved narrow sidewall varies to cause the effective large dimension of the waveguide assembly to change such that the combination of said changes results in a constant phase length for said waveguide body as said waveguide body expands or contracts with temperature.