Metal Patch Antenna
Communications
Metal Patch Antenna (NPO-TOPS-38)
An all-metal patch antenna with greater bandwidth and reduced susceptibility to electrostatic discharging
Overview
NASA's Jet Propulsion Laboratory has developed an all-metal patch antenna with improved physical stability and performance that can be readily formed into low-cost, lightweight phased array antenna systems for a variety of communications applications. Conventional patch antennas have narrow bandwidth and contain dielectric materials, which makes them unsuitable for use in environments with strong electron fluxes. Because the dielectric provides structural support to the patch, state-of-the-art patch antennas that minimize or eliminate the use of dielectric materials lack the mechanical stability to survive hostile environments, such as spacecraft liftoff. JPL's novel patch antenna improves the state of the art by using all-metal components to reduce susceptibility to electrostatic discharging, improve mechanical stability, and increase bandwidth.
The Technology
JPL's patch antenna comprises a conductive patch attached to a ground plane by a support post and a probe connector arranged to conduct electromagnetic energy to the conductive patch (for signal transmission) or from the conductive patch (for signal reception). The central support post improves the mechanical stability of the antenna and increases its bandwidth without significantly affecting its radiation pattern performance. The conductive patch can include ribs that extend from the center axis to the outer edges of the patch to stabilize it further.
An all-metal patch antenna has been fabricated and subjected to thermal and vibration testing. The antenna was thermally cycled three times from 135 °C to 120 °C; no damage to either the support post or the antenna was observed. In addition, the return loss was very close to pretest measurements, indicating essentially no hysteresis. The antenna was vibration tested using 40 g z-axis and 20 g x- and y-axis; the vibration frequency shifts were less than 5%, and no structural failures or signs of probe abrasion were observed.
Benefits
- Double-tuned antenna for transmission and reception at adjacent frequencies
- Eliminates the use of dielectric materials without compromising mechanical stability
- Support member increases antenna bandwidth to as much as 20% without compromising radiation performance
Applications
- Communication - space, military, commercial
Similar Results
Multi-and Wide-Band Single-Feed Patch Antenna
NASA's patch antenna technology exhibits higher operational bandwidth (on the order of 20%) than typical patch antennas (less than 10%) and can operate across integer-multiple frequency bands (e.g. S/X, C/X, S/C). Testing of the antenna design has demonstrated > 6dB of gain on both S and X bands (boresight), with an axial ratio of < 6dB and voltage standing wave ratio (VSWR) < 3:1 throughout the entire near-Earth network (NEN) operating bands (22.4GHz and 88.4GHz) with hemispherical coverage. The patch size is on the order of 10 x 10 cm and with associated electronics, is about 1 cm in height.
High Performance, All-Metal X-Band Patch Antenna
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.
Lightweight, Self-Deployable Helical Antenna
NASA's newly developed antenna is lightweight (at or below 2 grams), low volume (at or below 1.2 cm3), and low stowage thickness (approx. 0.7 mm), all while delivering high performance (at or above 10 dBi gain). The antenna includes a novel design-material combination in a helical coil conformation. The design allows the antenna to compress for stowage (e.g., satellite launch), then self-deploy at the desired time in orbit.
NASA's lightweight, self-deployable helical antenna can be integrated into a thin-film solar array (or other large deployable structures). Integrating antenna elements into deployable structures such as power generation arrays allows spacecraft designers to maximize the inherently limited resources (e.g., mass, volume, surface area) available in a small spacecraft. When used as a standalone (i.e., single antenna) setup, the the invention offers moderate advantages in terms of stowage thickness, volume, and mass. However, in applications that require antenna arrays, these advantages become multiplicative, resulting in the system offering the same or higher data rate performance while possessing a significantly reduced form factor.
Prototypes of NASA's self-deployable, helical antenna have been fabricated in S-band, X-band, and Ka-band, all of which exhibited high performance. The antenna may find application in SmallSat communications (in deep space and LEO), as well as cases where low mass and stowage volume are valued and high antenna gain is required.
Conformal, Lightweight, Aerogel-Based Antenna
This CLAS-ACT is a lightweight, active phased array conformal antenna comprised of a thin multilayer microwave printed circuit board built on a flexible aerogel substrate using new methods of bonding. The aerogel substrate enables the antenna to be fitted onto curved surface. NASA's prototype operates at 11-15 GHz (Ku-band), but the design could be scaled to operate in the Ka-band (26 to 40 GHz).
The antenna element design incorporates a dual stacked patch for wide bandwidth to operate on both the uplink and downlink frequencies with a common aperture. These elements are supported by a flexible variant of aerogel that allows the material to be thick in comparison to the wavelength of the signal with little to no additional weight. The conformal antenna offers advantages of better aerodynamics for the airframe, and potentially offers more physical area to either broadcast further distances or to broadcast at a higher data rate. The intended application for this antenna is for UAVs that need more than line of sight communications for command and control but cannot accommodate a large satellite dish. Examples may be UAVs intended for coastal monitoring, power line monitoring, emergency response, and border security where remote flying over large areas may be expected. Smaller UAVs may benefit greatly from the conformal antenna. Another possible application is a UAV mobile platform for Ku-band satellite communication.
With the expectation that 5G will utilize microwave frequencies this technology may be of interest to other markets outside of satellite communications. For example, the automotive industry could benefit from a light weight conformal phased array for embedded radar. Also, the CLAS-ACT could be used for vehicle communications or even vehicle to vehicle communications.
Novel Antenna Concept for CubeSat Platforms
The side walls and railing rods of a CubeSat are replaced by RF radiators that double as supporting structures. The RF radiators are hollow railing rods with inner dimensions that function as a waveguide to carry RF energy at a desired frequency. Radiating slots are cut on two of the four sides of hollow tubes tube that are open to outside environment. Different operating frequency antennas may be placed at each of the Cubesats four corners. Thus the railing rods provide RF antenna functionality in addition to structurally supporting the CubeSat structure.
While this technology was designed for Cubesats, it may be utilized in any technology that utilizes a structural frame. The advantages of this system are increased reliability due to the elimination of deployment mechanisms and decreased payloads. Higher frequency
antennas with increased gain and directivity may be embedded into the rails. These higher frequencies are especially useful for remote sensing.



