Transition arrangement comprising a waveguide twist, a waveguide structure comprising a number of waveguide twists and a rotary joint

A transition arrangement for interconnection of waveguide structures or waveguide flanges for forming a waveguide twist, wherein a waveguide twist section arrangement comprising a number of waveguide twist sections is arranged between the waveguide structures or waveguide flanges for rotating a polarization of waves or signals twisted or forming an angle with an adjacent waveguide flange and/or another adjacent waveguide twist section with respective waveguide openings, wherein further the, or each, twist section and/or waveguide flange on at least one side thereof comprises a surface of a conductive material with a periodic or quasi-periodic structure formed by a number of protruding elements arranged or designed to allow the waves to pass across a gap between the waveguide twist section and the waveguide structure or the waveguide flange and/or between the number of waveguide twist sections and another waveguide twist section in a desired direction or waveguide paths, at least in an intended frequency band of operation, and to stop propagation of waves in the gap in other directions, such that a connection or connections between the waveguide structures or waveguide flanges and the twist section arrangement is/are contactless, requiring no conductive contact, the surface or surfaces formed by the periodically or quasi-periodically arranged protruding elements not being in direct mechanical contact with an opposite, interconnecting, waveguide structure or waveguide flange or waveguide twist section, wherein the transition arrangement is arranged to form a waveguide twist with an arbitrary rotation angle smaller than or equal to +/−180°, and wherein a respective cavity is provided between each waveguide opening in the number of waveguide twist sections and/or waveguide structure or waveguide flange and the surrounding periodic or quasi-periodic structure of the respective waveguide twist section and/or waveguide structure or waveguide flange, hence introducing compensating capacitances to compensate for inductances introduced at the twist section interfaces.