Electromagnetically transparent plastics for high-frequency radome applications

Low loss plastic materials meet the stringent electrical requirements of high-frequency and high-power density applications. 5G telecommunications, high-speed aircraft, and communications satellites all depend on durable dielectric materials to protect antennas and critical radar systems. 

Plastic materials are lightweight, resistant to rain erosion, and have outstanding dielectric properties. Curbell supplies plastics suitable for indoor, outdoor, high-speed, and extreme temperature radome applications.

Plastics commonly used in radome applications include​:

Amorphous thermoplastics such as ABS, PMC® TPO, KYDEX® Thermoplastics, Boltaron®, and polycarbonate are easily manufactured into radomes by cost-efficient thermoforming techniques. These materials are available in a wide range of colors and textures to achieve aesthetically pleasing radome designs.

High-performance polyaryletherketones, fluoropolymers, and DuPont™ Vespel® polyimide can be machined into radomes suitable for demanding applications involving extreme temperatures, high speeds, and chemical exposure. Thermoset laminates such as FR-4 can also be machined into radomes where dielectric requirements are less stringent. 

Our plastic materials are available with the following characteristics:

  • Low dissipation factor
  • Low dielectric constant
  • High strength and modulus
  • High impact resistance
  • Low water absorption
  • Weatherability
  • Rain erosion resistance
  • UV resistance
  • Surface hydrophobicity
  • Machining and fabrication characteristics
  • Availability in many colors

These properties are critical to the effectiveness and long-term reliability of radomes.

Curbell assists with:

  • Plastic material selection
  • Plastic part design
  • Prototype development
  • Supply chain and inventory management
  • Cut-to-size sheet, rod, and tube
  • Machined plastic parts
  • Thermoformed plastic parts 

Why plastic materials for radomes

Many thermoplastics are virtually transparent to RF owing to exceptional dielectric properties. They also exhibit superior ductility and rain erosion resistance compared to conventional thermoset composite and ceramic materials.

Some thermoplastics can be thermoformed into deep-draw radome structures. This cost-effective manufacturing method is best suited for amorphous thermoplastics, however some semi-crystalline polymers such as PEKK, PEEK, and ETFE can be thermoformed with sophisticated tooling and tight control of processing conditions. Curbell partners with experienced thermoformers to achieve part detail and surface textures that compare to injection-molded parts without the prohibitive tooling costs and part minimums.

Curbell’s plastics experts can provide engineers with technical information so they can choose the best polymer for their specific radome or telecommunications application. 

Advantages of plastic materials for radomes

Some plastic materials are inherently UV stable and some are available with additives that extend service life in outdoor applications.

Dielectric Properties
Plastics generally have very low dissipation factors and dielectric constants. This allows RF signals to pass through with minimal attenuation.

Non-polar plastics, especially polyolefins and fluoropolymers, tend to be hydrophobic. The poor wettability of hydrophobic surfaces reduces moisture uptake, ice adhesion, and the accumulation of precipitation. Hydrophobic surfaces are typically difficult to paint or bond with adhesives without surface preparation.

Radomes must withstand potential foreign object impacts. High performance thermoplastics such as DuPont™ Vespel® remain relatively ductile across temperature extremes involved in demanding applications such as high-speed flight. For general-use outdoor radomes, TUFFAK® polycarbonate, KYDEX® Thermoplastics, Boltaron®, and thermoplastic polyolefins (TPOs) offer extraordinary toughness and ductility.

Plastics reduce the cost of telecommunications equipment by extending the life of electrical equipment. Radomes can be economically manufactured in small or large volumes by thermoforming plastic sheet stock with relatively inexpensive tooling.

Radomes manufactured from most thermoplastics are recyclable at the end of service. 

Fabrication and machining services

Take advantage of our plastic fabrication and machining services to save time and money on plastic parts. Utilizing in-house capabilities and partnering with fabrication specialists we provide customers with reliable fabrication solutions, machined parts and cut-to-size materials for any application.

Quote your project

Which plastic materials are right for your radome application? Contact us today.

With access to the latest high-performance materials — and the expertise to assist with selection and troubleshooting — Curbell Plastics can help you with all of your radome challenges.

Want to learn more? Download Plastic Materials for High Performance Radomes white paper.

We serve customers in all corners of the United States and Canada from locations nationwide. Multiple Curbell Plastics locations have ISO 9001 certification, and we maintain ITAR and EAR compliance company-wide.

Call 1-800-553-0335  |  Ask an expert  |  Explore our materials

Frequently Asked Questions
Can plastics be used in outdoor environments?

Certain plastics such as acrylic, Ultem® PEI, and PTFE are inherently UV stable. However, most plastic materials exhibit color change and a loss of ductility over time when exposed to UV light.

The UV resistance of plastics can be improved by adding UV stabilizers or UV resistant cap layers. UV stabilized grades of HDPE, ABS, and polycarbonate are commonly used in outdoor applications. KYDEX® Thermoplastics and Boltaron® thermoplastics are also available in UV stabilized grades.

Do plastics attenuate RF signals?

Many thermoplastics have excellent transparency to RF signals, characterized by a low dielectric constant and dissipation factor (loss tangent). In general, thermoplastics have superior dielectric properties compared to thermoset composite and ceramic materials. Plastic materials maintain good dielectric performance across wide operating frequencies and temperatures. Empirical testing should always be performed to evaluate the electrical performance of a radome in any application.

Can plastic materials save weight compared with composites?

Engineering plastics are approximately 3/4 the specific gravity of fiberglass composites like G10/FR-4. Plastics are often specified when weight savings are required.

How durable are plastic materials?

The toughness of plastic materials can be measured in a few ways including tensile elongation and notched izod impact strength. Some plastics including polycarbonate, KYDEX® Thermoplastics, Boltaron®, and thermoplastic polyolefins (TPOs) are extremely tough and ductile. These properties enhance the material’s resistance to impact and rain erosion.

Which plastics should I used for telecommunications applications?

ABS, polycarbonate, KYDEX® Thermoplastics and Boltaron® have excellent dielectric properties and toughness. They are available in various colors, textures, and UV stabilized grades. They can be easily manufactured into radomes by thermoforming.

Fluoropolymers and DuPont™ Vespel® are good choices for radomes subject to extreme environments. PCTFE and DuPont™ Vespel® maintain some degree of ductility in cryogenic environments.