A radiofrequency antenna is adapted to be mounted on a spacecraft. The radiofrequency antenna includes four helical strands of a super elastic shape memory alloy and is configured to move from a deployed configuration to a constrained stacking configuration and to return autonomously to the deployed configuration.

Provided herein is a deployable antenna assembly, a method of deploying an antenna, and systems and methods for sequentially deploying an extendable structure. The deployable antenna assembly includes an extendable pillar configured to extend in an axial direction along a deployment axis of the deployable antenna assembly to deploy an antenna. The extendable pillar includes at least one extendable element configured to convert between a stowed configuration and a deployed configuration where the deployed configuration is longer in the axial direction than the stowed configuration. The extendable pillar also includes a launcher configured to initiate conversion of the plurality of extendable elements from the stowed configuration to the deployed configuration, thereby extending the extendable pillar and deploying the antenna.

Systems and methods for improving an efficiency and a gain of a helical antenna. The methods comprise: configuring a conductive helix element of the helical antenna to comprise a proximal segment having a helical winding that extends along an axis of the conductive helix element and has a plurality of turns with linearly progressing pitch angles; configuring the conductive helix element to comprise a distal segment having a helical winding that extends along the axis of the conductive helix element and has a constant pitch angle; and coupling the distal segment to the proximal segment in a series arrangement so that a radio wave reaches a terminal velocity at a point of the coupling.

Systems, devices, and methods for providing deployable and collapsible Quadrifilar Helical Antennas (QHA) on small satellites to improve communications in low earth orbit satellites. Monopole antennas are very popular for use on small satellites, generally because they are relatively easy to attach. By using circularly polarized antennas for the spacecraft and the ground station, polarization losses are virtually eliminated. The QHA can be designed to have a wide range of circularly polarized antenna patterns. Low power transmitters are employed on the small satellite to be consistent with the available energy. The communication link budgets are dependent on good radiation pattern characteristics for the small satellite downlink where higher data rates are required. Quadrifilar Helical Antennas can be collapsed and stowed inside a module to mount inside typical cubes known as 1U through 27U size small satellites. After launch from the rocket, the QHA can be deployed to its stored memory shape. The QHA radiating filars can be made from Nitinol wires having an activation temperature above which the filars resume their stored memory shape acquired during heating treatments. QHA applies an electrical direct current onto the filars after launch of the small satellite independent of the radio frequency of the QHA.

A lightweight deployable antenna assembly for, e.g., microsatellites including multifilar (e.g., quadrifilar) antenna (MHA) structures rigidly maintained in an array pattern by a lightweight linkage and collectively controlled by a central antenna feed circuit and local antenna feed circuits to perform phased array antenna operations. The linkage is preferably an expandable (e.g., flexural-scissor-grid) linkage capable of collapsing into a retracted/stowage state in which the MHA elements are maintained in a closely-spaced (e.g., hexagonal lattice close-packed) configuration optimized for payload storage. To deploy the antenna for operation, the linkage unfolds (expands) such that the MHA elements are moved away from each other and into an evenly spaced (e.g., wide-spaced hexagonal) pattern optimized for phased array operations. The MHA structures utilize modified helical filar elements including metal plated/printed on polymer/plastic beams/ribbons, or thin-walled metal tubes. The helical filar elements are radially offset (e.g., by 90°) and wound around a central axis.

Systems and methods described herein include collapsible and deployable antenna structures including shape memory composite components.

An antenna for a portable communication device is provided. The antenna comprises an antenna body having an upper section and a lower section with a connection point therebetween. The connection point being configured to: couple the upper and lower sections during normal antenna operation; decouple the upper and lower sections in response to an impact event; and recouple the upper and lower sections after the impact event.

Embodiments of a wide band multi-polarization antenna system are described, which can be attached to the back or front of a soldier's vest or backpack. The antenna system can allow for release of pre-shaped integral radiating elements that spring into a geometric configuration suitable for circular polarization radiation or linear polarization over a desired band of frequencies. The antenna system can provide, when collapsed, linear polarized line-of sight capability over a wide band of frequencies. In a collapsed low-profile state, the antenna system can remain on the soldier, but out of the way for maneuvering.

The invention relates to a foldable/deployable structure (1) comprising: —a mast (4) which can be deployed along a longitudinal deployment axis, the mast being designed to be placed either in a folded state requiring little axial installation space, or in a deployed state having a predetermined shape, —a base (10) upon which the deployable mast (4) is rested, the structure (1, 2) further comprising a bracing device, the bracing device: —having at least three points for attachment to the base (10) and at least three points for attachment to the mast (4), the bracing device connecting the base to the mast; —being designed to limit the transverse movements of the mast relative to the base (10) at least when the mast (4) is in a deployed state, and; —comprising at least one connecting member (22, 42, 60) chosen from the group formed by fabrics, non-woven fabrics and ties, the ties being chosen from the group formed by monofilaments, cables, bundles and strips; the structure (1, 2) being characterised in that it comprises a device (30) for tensioning each connecting member of the bracing device when the mast (4) is in the deployed state, the tensioning device (30) enabling a proximal end of the mast (4) to be maintained in the deployed state, at a distance from the base (10) greater than the distance separating the proximal end of the mast (4) from the base (10) when the mast is in the folded state.

An antenna for a portable communication device is provided. The antenna comprises an antenna body having an upper section and a lower section with a connection point therebetween. The connection point being configured to: couple the upper and lower sections during normal antenna operation; decouple the upper and lower sections in response to an impact event; and recouple the upper and lower sections after the impact event.