An asymmetric, broadband, compact and low-PIM orthomode transducer comprised of two parts is presented. Mating of the two parts results in the formation of a choke flange as well as a critical impedance step which suppresses unwanted modes and enables broadband matching of the junction between the two parts. Furthermore, a cruciform-quatrefoil waveguide type is utilized that transitions to an aperture. This waveguide configuration can lead to a lower overall part length, an improved reflection, and reduced manufacturing costs.

A radiofrequency exciter comprises a junction including an axial access intended to be connected to a horn antenna, at least four lateral accesses and at least four frequency filters that are associated with the four lateral accesses, respectively, the junction including, in series, a first coupling cavity equipped with two coupling slots that are able to sample a vertical polarization, and a second coupling cavity equipped with two coupling slots that are able to sample a horizontal polarization, the four frequency filters being connected directly to the four respective coupling slots, the first coupling cavity having a transverse cross-section having a constant vertical dimension and a horizontal dimension that decreases between the axial access and a transverse exit aperture of the first coupling cavity.

Microwave antenna systems include a parabolic reflector antenna having a feed bore and a feed assembly. The feed assembly includes a coaxial waveguide structure that extends through the feed bore, a sub-reflector, and a first dielectric block that is positioned between the coaxial waveguide structure and the sub-reflector. The coaxial waveguide structure includes a central waveguide and an outer waveguide that circumferentially surrounds the central waveguide. One of the central waveguide and the outer waveguide extends further from the feed bore towards the sub-reflector than the other of the central waveguide and the outer waveguide.

An orthomode junction for separating and/or combining orthogonally-polarized radiofrequency wave signals, comprises a body which has a main cavity forming a main waveguide, which has a blind end, and auxiliary cavities forming auxiliary waveguides, which communicate laterally with the main cavity in the vicinity of the blind end thereof, and a deflection insert situated at the blind end of the main cavity and facing the auxiliary cavities, the deflection insert having different shapes on the side of the auxiliary cavities respectively.

An orthomode junction for separating and/or combining orthogonally-polarized radiofrequency wave signals, comprises a body which has a main cavity forming a main waveguide, which has a blind end, and auxiliary cavities forming auxiliary waveguides, which communicate laterally with the main cavity in the vicinity of the blind end thereof, and a deflection insert situated at the blind end of the main cavity and facing the auxiliary cavities, the deflection insert having different shapes on the side of the auxiliary cavities respectively.

A septumless polarizer is an OMT polarizer which is formed without a traditional thin septum which bridges the gap from the first assembly half to the second assembly half when the polarizer is split in the zero-current region of the rectangular waveguides (RHCP and LHCP ports). The septumless polarizer utilizes a dual-axis-stepped feature, which is included in one half of the polarizer only, creates the illusion of a traditional thin septum and actually improves performance. A close-proximity fastener scheme is enabled along with a fully encompassing pressure lip and contact pressure risks are mitigated.

Sealing portions of an orthomode transducer or another antenna component is accomplished by forming first and second receptacles or channels in one half or portion of the transducer and inserting first and second type of compressible sealing components into the receptacles. Upon attaching additional portions of the transducer the compressible sealing components may be compressed, but the compression is limited to an amount within a compression range to maintain a seal.

A method and apparatus forming an efficient and compact waveguide feed with all components for processing signals in multi-frequency band antenna feeds with single/dual linear/circular polarizations with/without tracking. This layout results in a very compact feed, which has excellent electrical characteristics, is mechanically robust, eliminates flange connections between components, and is very cost effective. The new layout eliminates the dummy ports and bends at least one filter element is bent to an acute angle, thereby enabling a high density packaging of the microwave feed network; and wherein a plurality of single sided corrugations are located along the bent filter element. In this design high density arrays of feeds can be realized for satellite communication.

Apparatus is provided to allow the reception and/or transmission of data signals at two different frequency bands. The apparatus includes a waveguide (4) which has a first section (6) of larger cross sectional area for receiving and/or transmitting the lower frequency band signals, and a reducing section (8) which leads to a section with a reduced cross sectional area in comparison to the first section (6) and this allows the receipt of the higher frequency band signals. In one embodiment sections of the waveguide can be rotated to allow the apparatus to be adjusted to any particular orientation to suit the particular circular polarity transmission type at the location at which the apparatus is provided at that time.

Apparatus is provided to allow the reception and/or transmission of data signals at two different frequency bands. The apparatus includes a waveguide (4) which has a first section (6) of larger cross sectional area for receiving and/or transmitting the lower frequency band signals, and a reducing section (8) which leads to a section with a reduced cross sectional area in comparison to the first section (6) and this allows the receipt of the higher frequency band signals. In one embodiment sections of the waveguide can be rotated to allow the apparatus to be adjusted to any particular orientation to suit the particular circular polarity transmission type at the location at which the apparatus is provided at that time.