High Performance, All-Metal X-Band Patch Antenna
Communications
High Performance, All-Metal X-Band Patch Antenna (GSC-TOPS-361)
Rugged design and excellent performance in a small package
Overview
Innovators at NASA’s Goddard Space Flight Center have developed an all-metal, X-band patch antenna with built in choke rings and a polarizer circuit to meet the stringent requirements of high-precision space navigation antennas for the Geodetic Reference Instrument Transponder for Small Satellites (GRITSS) mission. GRITSS required a low-gain antenna with strong multipath mitigation and a stable phase center.
Typical dielectric-patch antennas can be high-loss, susceptible to manufacturing variability, have limited power handling ability, and are temperature sensitive. Compared to commercially available path antennas, NASA’s antenna is more rugged, provides a high front-to-back ratio, mitigates multipath signal interference, and is capable of higher power handling. NASA’s X-band antenna was designed to be mounted on a CubeSat but has the potential of being mounted on terrestrial aircraft and vehicles for either communication or radar applications.
The Technology
The patch antenna consists of two radiating metal patch elements, a metal feed circuit, choke rings, several alignment spacers, a SMA connector, and a mounting lid giving the antenna a total diameter of 54 mm; small enough to fit in a coffee cup. The signal is carried between the lower patch and the circuit via a coaxial transmission structure, in which the probes are the inner conductor and the antenna structure is the outer conductor. The patch antenna is constructed entirely of metal, offering rugged physical durability while delivering superior performance. This advanced material not only enables the antenna to handle higher power loads (exceeding 10 watts) but also ensures exceptional stability under demanding conditions—outperforming standard patch antennas made with traditional dielectric materials. It is also not susceptible to the manufacturing variability incurred from using dielectrics. Ideally, this metallic design also allows for reentry and reuse across missions.
The patch antenna is designed with integrated choke rings to effectively mitigate multipath signal interference, delivering an impressive front-to-back ratio of over 35 dB. Its integrated polarizer circuit enhances signal clarity and boosts overall efficiency, ensuring reliable communication in challenging environments. With support for both right- and left-handed circular polarization, the antenna achieves a co-polarization peak gain of 9 dBi and an axial ratio of less than 3 dB within a wide 50-degree orientation range. These advanced features provide superior signal performance and consistent clarity across diverse applications.
Although designed for space and planetary exploration applications, the antenna may also be valuable for terrestrial use cases with rugged conditions. The X-band patch antenna is at technology readiness level (TRL) 5 (component and/or breadboard validation in relevant environment) and is available for patent licensing.
Benefits
- Robustness: All-metal construction provides environmental robustness, increased radiation tolerance, and supports high power loads.
- Compact design: Layered construction is leveraged to enable miniaturization; NASA’s X-band patch can fit inside a coffee mug.
- Precision: Designed for very-long-base interferometry (VLBI), the built in choke rings provide consistent, repeatable signals.
- Efficiency: Integrated polarizer circuit increases probability of successful link without need for rotation.
Applications
- Aerospace: Originally designed for integration into satellites, spacecraft, and planetary exploration vehicles.
- Telecommunications: X-band frequencies are used in broadband networks, air traffic control, and maritime vessel traffic control.
- Aerospace and Defense: Implementation into UAV and other aircraft communications systems requiring operation in austere environments.
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