N101-105 TITLE: High Performance UHF Antenna for Nano-satellites

TECHNOLOGY AREAS: Electronics, Space Platforms

ACQUISITION PROGRAM: Mobile User Objective System (MUOS)

OBJECTIVE: Develop a high performance UHF antenna for use in nano-satellites.

DESCRIPTION: Nano-satellites are popular among universities and gaining momentum with commercial and government organizations. Standards based satellite buses and deployment mechanisms, such as the CubeSat and Poly Pico-satellite Orbital Deployer (P-POD), have stimulated growth in the area. Small satellites have proven capable and cost effective in many areas traditionally dominated by large satellites, however many challenges remain.

To date nano-satellites have primarily used relatively limited communications packages using amateur radio bands. The UHF band provides relatively low link loss and thus requires less power than higher frequency systems. However, lower frequencies have a greater wavelength, generally requiring larger, more massive antennas.

New research is needed to improve the capability of nano-satellite antennas. Current quarter-wave, dual-dipole, steel-tape UHF antennas provide approximately 5 dB of gain at the 70cm amateur band. A next generation antenna should provide significantly increased gain over a wide range of operational frequencies. The goal is to provide at least 11 dB gain over 280 MHz to 400MHz.

One important consideration in developing a new nano-satellite antenna is mission life. Many nano-satellites are deployed in Low Earth Orbit (LEO) where atmospheric drag is considerable. Since most nano-satellites do not carry propellant for station keeping, atmospheric drag is often a mission life limiting factor. The antenna�s impact on mission life must be weighed in the design process.

A high performance UHF antenna will enable nano-satellites to expand from university experiments to operational missions. The antenna must meet the CubeSat Design Specification. Designs that fit in the 1U form factor are desired, however larger designs that provide significantly increased capability within the 3U form factor will be considered.

PHASE I: Develop an innovative UHF antenna design for CubeSats.

Tasks under this phase could include:
� Develop a UHF antenna design
� Predict system performance using modeling and simulation or other tools
� Estimate mass and volume requirements
� Estimate the design�s impact on atmospheric drag

PHASE II: Build a prototype antenna and test it in the space environment.

� Optimize the antenna design
� Demonstrate operation of the prototype in a space environment such as thermal vacuum.
� Evaluate measured performance characteristics versus expectations and make design/process adjustments as necessary.

PHASE III: This phase will focus on integrating the UHF antenna into potential military CubeSat missions.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: This technology can be applied to a variety of commercial, military and space exploration nano-satellite missions.

REFERENCES:
1. CubeSat Design Specification REV. 11, http://cubesat.calpoly.edu/

2. M. Tamamoto, "Active Antennas and UHF Antennas for CubeSat Applications"

3. D. Ichikawa, "CubeSat-to-Ground Communication and Mobile Modular Ground-Station Development"

KEYWORDS: Nano Satellites, UHF antenna

** TOPIC AUTHOR (TPOC) **

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