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At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS2019

Deployment mechanisms for high packing efficiency One-MEter Reflectarray Antenna (OMERA)

While the capabilities of CubeSats have greatly increased in the past years, large, deployable high frequency apertures remain a limitation. The goal of this work is to develop a large 1 meter antenna operating at 35.75 GHz for RADAR applications. A reflectarray design was selected, as the flat panels are compatible with the CubeSat form factor. A center-fed, Cassegrain configuration was selected for the feed, to minimize deployed height. The flat panel configuration and Cassegrain feed allowed the entire 1 meter antenna to be compatible with a 6U bus, leaving a little under 4U of volume for remaining instrument and spacecraft components. Several iterations of the design have been built and tested, with an RF test of a fully deployed assembly being completed most recently. Prior to constructing the flight model, another iteration will need to be built and tested. The goal is to have the antenna flight ready before 2020.

Cwik, Tom↗
NASA NTRS2019

Deployment Mechanisms for High Packing Efficiency OneMeter Reflectarray Antenna (OMERA)

While the capabilities of CubeSats have greatly increased in the past years, large, deployable high frequency apertures remain a limitation. The goal of this work was to develop a large 1 meter antenna operating at 35.75 Ghz for RADAR applications. A reflectarray design was selected, as the flat panels were compatible with the CubeSat form factor. A center-fed, Cassegrain configuration was selected for the feed, to minimize deployed height. The flat panel configuration and Cassegrain feed allowed the entire 1 meter antenna to be compatible with a 6U bus, leaving a little under 4U of volume for remaining instrument and spacecraft components. Several iterations of the design have been built and tested, with an RF test of a fully deployed assembly being completed most recently. The goal is to have the antenna flight ready before 2020.

Cwik, Tom↗
NASA NTRS2022

Design of Flexures for Deployable Reflectarrays Using High Strain Composites

This paper presents a novel flexure design for small scale refelectarrays, specifically CubeSats, that requires high level of deployment precision. Advantages of using a HSC flexure includes additional thermal stability, lesser part count and passive deployment mechanism using the stored strain energy. The proposed design is to use two flat HSC strips of thickness ℎ, length 2𝐿ℎ, width 𝑊ℎ that attach to the core-reflector panel interface. The flexure satisfies two main requirements: ability to fold to a specific compaction 𝑑 without material failure and sufficient stiffness in the deployed configuration. The elastica analysis was implemented to identify the maximum strains in the flexure when folded and provide relations that combine Δ, ℎ, 𝐿ℎ with the maximum allowable strain. A simplified analysis was performed of the vibration of a panel-flexure combination using a two degree of freedom system. The vibration analysis reveals a dimensionless length parameter 𝛽 = (𝐿ℎ/𝐿𝑃) (Δ/ℎ) that determines the transition between bending and shear modes. A non-dimensional relationship was obtained between the natural frequency and 𝛽 that captures the impact of each parameter on the response of the structure. Our current work involves fabricating and testing of the proposed flexures using High Strain Composite materials, with plans to build a prototype for a deployable reflectarray.

López Jiménez, Francisco↗
NASA NTRS2000

3-Meter Ka-Band Inflatable Microstrip Reflectarray

In order to meet the increasingly stringent budget constraints for space missions, NASA is currently developing lightweight spacecrafts with reduced stowed volume but with increased capabilities.

inflatable reflectarray microstrip antenna↗
NASA NTRS2011

Evaluation of the Reflection Coefficient of Microstrip Elements for Reflectarray Antennas

Basis functions were studied and identified that provide efficient and accurate solutions for the induced patch currents and the reflection phase in microstrip reflect arrays. The integral equation of an infinite array of microstrip elements in the form of patches or crossed dipoles excited by a uniform plane wave is solved by the method-of-moments. Efficient choices of entire domain basis functions that yield accurate results have been described.

Rengarajan, Sembiam↗