Apparatus for dual-band antenna and communications tower comprising such apparatus are provided. The apparatus comprises a first part (202) comprising first and second propagation paths configured to selectively propagate signals of a first frequency with either a first polarization state or a second polarization state, a transition part (204) rotatable between first and second transition positions to selectively propagate signals of a second frequency along the second signal path with the first polarisation state when in the first transition position and with the second polarisation state when in the second transition position and a rotator part rotatable between first and second rotator positions. Wherein, the rotator part is configured to orientate the polarisation of signals in the second signal path in order to couple the second signal path to an interface, and allow propagation of signals in the first signal path in either the first or second rotator positions.

In an example embodiment, a waveguide device comprises: a first common waveguide; a polarizer section, the polarizer section including a conductive septum dividing the first common waveguide into a first divided waveguide portion and a second waveguide divided portion; a second waveguide coupled to the first divided waveguide portion of the polarizer section; a third waveguide coupled to the second divided waveguide portion of the polarizer section; and a dielectric insert. The dielectric insert includes a first dielectric portion partially filling the polarizer section. The conductive septum and the dielectric portion convert a signal between a polarized state in the first common waveguide and a first polarization component in the second waveguide and a second polarization component in the third waveguide.

A compact radiofrequency driver includes at least one axial port intended to be connected to a radiating antenna, at least one output intended to collect received signals and at least one input intended to transmit signals, comprising first and second septum polarizers and a frequency filter, the second polarizer being connected, via its common port, to a first rectangular port of the first polarizer and the frequency filter being connected to the second rectangular port of the first polarizer and being configured to filter a reception or transmission frequency band, these two bands being different, and wherein at least one of the polarizers is configured to convert a circularly polarized signal received on said axial port of the driver into a linearly polarized signal in a reception frequency band and in that at least a second polarizer is configured to convert a linearly polarized signal transmitted to the driver by the input into a circularly polarized signal in a transmission frequency band.

A square waveguide (1) has four ridges (6a, 6b, 7a, 7b). The cross section of the square waveguide (1) perpendicular to a waveguide axial direction is square. Inside the square waveguide (1), two rectangular waveguide terminals (4, 5) are formed by partitioning the inside along the waveguide axial direction. A septum phase plate (2) formed to get narrower stepwisely as its gets closer to a square waveguide terminal (3) opposite to the rectangular waveguide terminals (4, 5) is provided. A projecting portion (8) is provided on a part of a ridge (7b) formed on a ridge-side wall surface opposite to a wall surface, the septum phase plate (2) being joined to the wall surface in a part where the septum phase plate has largest width, the projecting portion (8) being larger than other parts of the ridge (7b) in a cross-sectional shape perpendicular to the waveguide axial direction.

An antenna includes a reflector and a waveguide assembly. The waveguide assembly includes a feed assembly and a support member that extends from behind the reflector to orient the feed assembly for direct illumination of the reflector. The waveguide assembly includes a first waveguide coupled to a first portion of a common waveguide, a second waveguide coupled to a second portion of the common waveguide, and a septum layer that includes a septum polarizer coupled between the common waveguide and the first and second waveguides.

An antenna includes a reflector and a waveguide assembly. The waveguide assembly includes a feed assembly and a support member that extends from behind the reflector to orient the feed assembly for direct illumination of the reflector. The waveguide assembly includes a first waveguide coupled to a first portion of a common waveguide, a second waveguide coupled to a second portion of the common waveguide, and a septum layer that includes a septum polarizer coupled between the common waveguide and the first and second waveguides.

A polarizer for a waveguide, comprising a main body for transmitting an electromagnetic wave, a first delay member being provided in the main body. A second delay member arranged downstream of the first delay member in the working direction (A) of the electromagnetic wave is provided in the main body, and the polarization axis (P.sub.2) of the second delay member is rotated relative to the polarization axis (P.sub.1) of the first delay member by a delay angle (β).

A polarizer for a waveguide, comprising a main body for transmitting an electromagnetic wave, a first delay member being provided in the main body. A second delay member arranged downstream of the first delay member in the working direction (A) of the electromagnetic wave is provided in the main body, and the polarization axis (P.sub.2) of the second delay member is rotated relative to the polarization axis (P.sub.1) of the first delay member by a delay angle (β).

The described features include a scalable waveguide architecture for a waveguide device. The waveguide device may be split into one or more waveguide blocks instead of manufacturing increasingly larger single-piece waveguide devices. Described techniques provide for a radio-frequency (RF) seal between such waveguide blocks that may facilitate greater manufacturing tolerances while maintaining an effective RF seal at the junction of the waveguide blocks. The described techniques include channels within one or more waveguide blocks opening to the dielectric gap between the waveguide blocks. The channels may, for each of multiple waveguides joined at the interface between waveguide blocks, be included in one or both waveguide blocks and may be in a single waveguide dimension relative to the multiple waveguides, or extend for more than one waveguide dimensions.

A non-reciprocal microwave network is provided that includes an in-line ferromagnetic element [1010] with adjoining polarizing adapters [1002, 1004, 1006, 1008] to achieve directivity via a multi-mode interaction at or near the ferrite to act as new class of 4-port circulator or 2-port isolator, with standard waveguide inputs for assembly in larger networks.