Subreflectors for frequency-reuse types of satellite communication system which cover the S and C bands take the form of a three-dimensional waveguide with cross dipoles on each end, where each branch of each dipole is electrically connected by conductor that passes through the center of a substrate that fills the volume of the waveguide. The frequency selective surface sub-reflector is configured to permit the S-band antenna to transmit therethrough with an insertion loss of less than 0.5 decibels, and to reflect transmissions of the C-band antenna with transmissions through the frequency selective surface sub-reflector being less than 15 decibels.

Subreflectors for frequency-reuse types of satellite communication system which cover the S and C bands take the form of a three-dimensional waveguide with cross dipoles on each end, where each branch of each dipole is electrically connected by conductor that passes through the center of a substrate that fills the volume of the waveguide. The frequency selective surface sub-reflector is configured to permit the S-band antenna to transmit therethrough with an insertion loss of less than 0.5 decibels, and to reflect transmissions of the C-band antenna with transmissions through the frequency selective surface sub-reflector being less than 15 decibels.

Parabolic reflector antennas advantageously support low side lobe radiation patterns for ETSI class 4 performance, by utilizing: (i) metal choke plates adjacent a distal end of a dielectric cone within a sub-reflector assembly, (ii) “lossy” material feed boom waveguide sleeves and/or (iii) extended length cylindrical shields lined with radiation absorbing materials. Relatively shallow and large diameter parabolic reflectors having an F/D≤ratio of greater than about 0.25 may be provided with one or more of the identified (i)-(iii) enhancements.

An apparatus, for example a multi-band radio frequency antenna system, comprising: a primary reflector, for example a parabolic reflector; and a near-field feed arrangement comprising: a multi-band waveguide feed comprising a first waveguide feed for a first frequency band and a second waveguide feed for a second frequency band separate to the first frequency band, wherein the first waveguide feed and the second waveguide feed are co-axial and have, respectively, a first aperture and a second aperture; and a splashplate located within the near-field of the first waveguide feed, located within the near field of the second waveguide feed and configured as a feed for the primary reflector.

An apparatus, for example a multi-band radio frequency antenna system, comprising: a primary reflector, for example a parabolic reflector; and a near-field feed arrangement comprising: a multi-band waveguide feed comprising a first waveguide feed for a first frequency band and a second waveguide feed for a second frequency band separate to the first frequency band, wherein the first waveguide feed and the second waveguide feed are co-axial and have, respectively, a first aperture and a second aperture; and a splashplate located within the near-field of the first waveguide feed, located within the near field of the second waveguide feed and configured as a feed for the primary reflector.

The invention includes various embodiments of integrated dual-band printed antenna feeds having various combinations of electrical and structural components for use with a prime focus, ring focus, or Cassegrain dish antennas. All of the embodiments of dual-band antenna feeds disclosed herein are configured to be fabricated as a single structure using metal additive manufacturing techniques.

A phased array antenna comprises an array of reflective cells, each cell being defined by a wall positioned within the array the wall arranged to define a waveguide, and having a moveable reflector positioned within the wall. Each reflector is arranged such that it is not in electrical contact with its respective wall and such that, in use it can be moved to tune the antenna. A feed and subreflector are positioned within the array and arranged to transmit and/or receive electromagnetic signals to and/or from the array.

Antenna apparatus and spacecraft to be deployed in a more easily stored state are disclosed. In an example of the disclosed technology, and antenna apparatus includes: a main-reflection unit including a plurality of ribs formed to be deployable in a stored state in which the ribs are folded and a sheet body provided between a plurality of the ribs and configured to be capable of reflecting a radio wave radiated from a radiator and emitting the radio wave outside, and a restriction member configured to restrict deployment of the plurality of ribs in the stored state, and release the restriction by operation of a restriction release member different from the main-reflection unit.

Antenna apparatus and spacecraft to be deployed in a more easily stored state are disclosed. In an example of the disclosed technology, and antenna apparatus includes: a main-reflection unit including a plurality of ribs formed to be deployable in a stored state in which the ribs are folded and a sheet body provided between a plurality of the ribs and configured to be capable of reflecting a radio wave radiated from a radiator and emitting the radio wave outside, and a restriction member configured to restrict deployment of the plurality of ribs in the stored state, and release the restriction by operation of a restriction release member different from the main-reflection unit.

Antenna apparatus and spacecraft to be deployed in a more compactly stored state are disclosed. In an example of the disclosed technology, a spacecraft includes: a main-reflection unit configured to reflect and emit a radio wave outside, a sub-reflection unit configured to face the main-reflection unit, a radiator arranged to face the sub-reflection unit and configured to radiate the radio wave in a direction of the sub-reflection unit, a main body configured to be able to accommodate at least one part of the sub-reflection unit therein, and a delivery device connected to the sub-reflection unit and configured to deliver the sub-reflection unit, at least one part of which is accommodated in the main body, to a position where the sub-reflection unit is able to reflect the radio wave radiated from the radiator to the main-reflection unit and cause the main-reflection unit to radiate the radio wave outside.