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Deployable Electronically Steered Apertures (ESAs) for Future Space Platforms

Description:

TECHNOLOGY AREA(S): Space Platforms

OBJECTIVE: The objective of this work is to develop a low-cost, compactly folded aperture approach to replace traditional active phased array antennas for future satellite architectures.

DESCRIPTION: Multibeam steerable antennas are currently used to provide secure communications for a variety of protected and unprotected missions. Improved coverage and capacity is needed. Phased array antennas are desired because more beams can be transmitted and rapidly repositioned arbitrarily for a large number of users. The problem is that high performing phased array antennas are complex and expensive requiring extensive parts list and specialized NRE for each iteration on a given platform. With the limited procurement volumes seen in the space sector, new antenna options are needed that can be procured for less than $1M/m^2 and that can be reconfigured or modularized to meet a variety of RF parameters. Additionally, these antennas need to function as the same aperture for both transmit and receive frequencies for their respective platform. Frequencies used on heritage AF space systems, such as AEHF, Milstar, WGS, etc. are available in open literature. While one single aperture solution may not be able to handle all frequencies for future versions of these systems, it is of interest to capture as much of the spectrum as possible (TX: 7.3, 20, and 73 GHz; RX: 8, 30, 44 and 83 GHz; Cross-link 60 GHz). This may be achievable, for example, using wideband antenna elements combined with RF MEMS or other reconfigurable approaches. Regardless of the approach proposed, authors should plan to explain the appropriateness of a given technology for a space environment consisting of thermal cycle extremes, launch loads, and space radiation induced effects. Thermally induced deformations and the effect on antenna performance must also be addressed.

Phased array antenna technologies are needed with reduced complexity feeds, simpler tuning and phase shifting architectures, reduced overall size and mass, and reduced touch labor required to assemble and integrate. Single feed solutions, similar in principle to a reconfigurable reflectarray, are desired that are capable of both transmit and receive across all the frequency bands of interest, where the reconfiguration of the reflector can be done with low power phase shifting solutions such that all the sensitive, high-powered feed requirements may be limited to the single feed element rather than an array of coupled amplifiers and phase shifters to tune individual or grouped elements. Proposers should not focus solely on approaches limited to a reflectarray approach, which is only offered as one example of a reduced feed Electronically Steered Array.

Future space architectures may disaggregate or augment these communications functions across multiple satellites, either as free-flyers or as hosted payloads on commercial satellites. In order to provide options for smaller spacecraft platforms and hosted payloads in LEO, HEO, and GEO orbits, apertures are additionally desired that can be folded or packaged in some stowed fashion for launch and deployed once on-orbit. Deployable structures are desirable but only if proposed as an antenna system solution. The desire is to fit as large of an aperture as possible onto a 10 kg to 100 kg class spacecraft.

PHASE I: Design, simulate, and build antenna hardware components with focus on proving the antenna critical function. Solution should be producible such that AFRL can verify performance with traditional network analyzer and waveguide setups. Proposers should also begin to form partnerships with payload or prime contractors that have potential to transition into military satellite communications systems.

PHASE II: Fabricate and produce a sub/full aperture brassboard antenna with focus on ground test and evaluation. Include flight qualifiable aspects to the antenna design where possible. Form stronger partnerships with payload or prime contractors that have potential to transition into military satellite communications systems.

PHASE III DUAL USE APPLICATIONS: Build full-scale flight qualifiable antenna that may be tested in a relevant ground or space environment.

REFERENCES:

  • Osterthaler, T., "Commentary: Satcom Reboot." C^4ISR Journal. June 2012. Pp 28-30.
  • Pawlikowski, E., Loverro, D., Cristler, T., "Space Disruptive Challenges, New Opportunities, and New Strategies" Strategic Studies Quarterly, Spring 2012, pp. 27-54.
  • Warren, P., Steinbeck, J., Minelli, R., Mueller, C., “Large, Deployable S-Band Antenna for a 6U Cubesat,” 29th AIAA/USU Conference on Small Satellites, SSC15-VI-5. Logan, Utah. 2015.
  • Fuchi, K., et al., "Resonance Tuning of RF Devices Through Origami Folding," 20th International Conference on Composite Materials, Copenhagen, 19-24 July 2015.

KEYWORDS: Milsatcom, Phased Array, Reflector, Beam Steering, Electronically Steered Antenna, Space Antenna, Deployable Antenna

 

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