Waveguides

A waveguide comprising first and second waveguide sections, each waveguide section comprising a main body portion 12 and a connecting end (14), said first and second waveguide sections being longitudinally aligned to define a conduit therethrough with a butted interface 28 therebetween, the waveguide further comprising a sleeve member 22 over said butted interface 28, wherein at least one cavity 19a is defined between an inner surface of said sleeve member 22 and an outer surface of a connecting end of at least one of said first and second waveguide sections, said at least one cavity 19a having a chemical adhesive therein operative to join said first and second waveguide sections together. Aspects include at least one of said first and second waveguide sections has a pair of circumferential, spaced apart ridges 16, 20 on its outer surface, said ridges defining a groove 17, wherein said cavity is defined between an inner wall of said sleeve member and said groove.