A waveguide polarizer for converting between a linearly polarized electromagnetic field in a first waveguide and a circularly polarized electromagnetic field in a second waveguide is provided. The waveguide polarizer includes a structure interconnecting the first and second waveguide which includes a waveguide excitation arrangement with a bifilar helical shape. A circularly polarized antenna arranged to be connected to the first waveguide of the waveguide polarizer and a satellite arrangement are also provided.

Microwave antenna systems include a parabolic reflector antenna and a dual-band feed assembly. The dual-band feed assembly includes a coaxial waveguide structure and a sub-reflector. The coaxial waveguide structure includes a central waveguide and an outer waveguide that circumferentially surrounds the central waveguide. The sub-reflector is mounted proximate the distal end of the coaxial waveguide structure.

An antenna is provided for a satellite in a satellite communication system. The antenna includes an array of radiators each having a dual linear-to-circular polarizer. The array of radiators is aligned in a first plane and configured to generate an elliptical beam having a desired narrow beamwidth in the first plane. Conductive walls provided around an aperture of each radiator in the array of radiators may narrow a wider beamwidth of the elliptical beam in a second plane orthogonal to the first plane to a desired value.

In one example an apparatus is provided. The apparatus includes a low frequency radiator, a high frequency radiator, a high frequency waveguide that carries high frequency bands to the high frequency radiator, a low frequency coaxial waveguide coupled to the high frequency waveguide in a coaxial structure, wherein the low frequency coaxial waveguide carries low frequency bands to the low frequency radiator and a low frequency combiner in communication with the low frequency coaxial waveguide, wherein the low frequency combiner comprises a circular low frequency waveguide and air dielectric transmission lines formed by air channels formed above and below a plurality of printed circuits in a metal housing.

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 linear-to-circular polarizer antenna is disclosed. In accordance with embodiments of the invention, the polarizer antenna includes an antenna operable to transmit and receive polarized signals and a linear-to-circular polarizer coupled to the antenna. The polarizer includes a plurality of cascaded elements, waveplates or anisotropic sheets, having biaxial permittivity. Each cascaded element has a principal axis rotated at different angles relative to an adjacent element about a z-axis of a 3-dimensional x, y, z coordinate system, and each element is composed of an artificial anisotropic dielectric. The polarizer further includes impedance matching layers disposed adjacent the cascaded elements.

The invention relates to a microwave circular polarizer including: a first outer conductor; a second outer conductor connected to the first outer conductor forming a first step discontinuity therewith; and a third outer conductor connected to the second outer conductor forming a second step discontinuity therewith. An inner conductor is provided which extends inside and is spaced apart from the first, second and third outer conductors. The first and second outer conductors are axially asymmetric with respect to the inner conductor, and the third outer conductor is axially symmetric with respect to the inner conductor. The microwave circular polarizer includes first and second rectangular waveguide ports in signal communication with an internal cavity through, respectively, a first rectangular aperture and a second rectangular aperture formed through the first outer conductor. The microwave circular polarizer further includes a first septum and a second septum.

An antenna feed includes a waveguide having a main part in hollow straight cylinder form extending in a direction, a radiating element, comprising ridges extending inwards and several treads along the direction, the number, the heights and the thicknesses of the treads being configured to allow a variation of impedance of the radiating element, a polarizer comprising two inputs separated by an internal leaf extending in the direction, and an output corresponding to the input of the radiating element, the internal leaf comprising several levels configured to transform a circularly polarized electromagnetic field into linear polarization, the polarizer comprising ridges extending inwards, the radiating element and the polarizer being made of a single piece, and disposed end-to-end in the direction, and a third portion comprising a filter, the internal leaf being prolonged in or part all of the third portion, the filter comprising a set of frequency filtration posts disposed inside the third portion and on one and the same surface of the internal leaf, the output of the filter corresponding to one of the two inputs of the polarizer, the third portion further comprising third ridges extending inwards and over all or part of the length of the third portion, the third ridges and the internal leaf being regularly distributed around the perimeter of the third portion; the radiating element, the polarizer and the filter being made of a single piece, preferably produced by an additive manufacturing technique, and the polarizer and the filter being disposed end-to-end in the longitudinal direction.

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 waveguide structure for a compact and scalable dual-polarized antenna array. In one example, a waveguide device comprises septum polarizers dividing common waveguides into first waveguides associated with a first polarization and second waveguides associated with a second polarization. The sets of septum polarizers may be inverted relative to each other to form first groups of four adjacent first waveguides for each type of waveguide. The waveguide device may also include a waveguide feed network including a first waveguide feed stage including waveguide combiner/dividers coupled between the four adjacent waveguides intermediate waveguides. The waveguide device may further include a second waveguide feed stage coupled with the first intermediate waveguides and the second intermediate waveguides, wherein the second waveguide feed stage extends in a direction perpendicular to the first waveguide feed stage.