Base stations

Low dielectric constant materials for 5G communication base stations

Modified PPE resin XYRON™ for 5G base stations

The relative dielectric constant (Dk) and dissipation factor (Df)  of the materials that make up 5G communication products and components are key points. In base stations, the relative permittivity and dielectric loss tangent must be controlled to match the component and its location in order to transmit radio waves more efficiently. In addition, base stations are equipped with a large number of metal or ceramic filters, which increase the weight, installation man-hours, and workload. Lightweighting the cover, housing, filters, and antennas by using resin and integrating them into complex shapes will contribute to the development of the 5G communication environment.

Asahi Kasei recommends the XYRON™ modified polyphenylene ether (PPE) resins as materials for 5G base stations. The XYRON™ family, which Asahi Kasei has been producing since 1979, boasts an extensive track record—occupying a key role in the history of engineering plastics—and today encompasses an extensive lineup of polymer alloys. In addition to their high heat resistance, they boast excellent flame retardance and electrical insulation, dimensional stability over a wide range of temperatures, and water resistance, as well as low specific gravity. These polymer alloys combine the advantages of PPE with the specialized properties of various other resins to yield unique functional materials.

XYRON™, whose low dielectric constant (Dk) and low dissipation factor (Df) make it well-suited for use in information and communications field.​​PPE, the main raw material of  PPE also features a high glass transition temperature, and its dielectric properties are less temperature-dependent than those of other high heat-resistant resins. These are important advantages for ensuring stable, high-quality communication across a wide range of operating temperatures.

Comparison of dielectric properties of each engineering plastic (non-reinforced)
Comparison of dielectric properties of each engineering plastic (non-reinforced)

Below, we propose each grade of XYRON™ for each component of a 5G base station. (Click to see details)

Asahi Kasei recommends the XYRON™ modified polyphenylene ether (PPE) resins as materials for 5G network base stations.

For 5G base-station antenna covers (radome) xyron 443Z・AA181-7(under development)・345Z (under development)

We propose XYRON™ low-dielectric, flame-retardant V-0 grade 443Z, under development material AA181-7, and low yellowing grade under development material 345Z as materials for 5G communication base station antenna covers (radomes).

The XYRON™ family of materials is the right choice to satisfy a wide range of specifications for 5G base-station antenna covers.


Property Units Test Method Test condition XYRON™ 443Z Under development
Under development
XYRON™ AA181-7
Features Low yellowing Improved dielectric propertie
DTUL ISO 75-1 1.8MPa 108 96 108 124
Flammability UL94 V-0
V-0 eqiuv.
V-0 eqiuv.
Dielectric Constant SPDR method 10GHz 2.7 2.9 2.6 2.9
Dissipation Factor 10GHz 0.0046 0.005 0.0017 0.0078
Charpy Impact Strength kJ/m2 ISO 179 23℃/50%RH 42 35 46 75

Low dielectric and flame retardant V-0 grade 443Z・AA181-7 (under development)

XYRON™ low dielectric and flame retardant V-0 grade has excellent hydrolysis resistance and high impact resistance, and has achieved flame retardancy UL94 V-0 in all colors.​

The antenna cover (radome), which is the outermost part, must not only be lightweight and weather resistant, but also have low dielectric properties to improve radio wave transparency. XYRON™ low dielectric flame retardant V-0 grade achieves both flame retardancy (UL94 V-0) and low dielectric properties, which was difficult to achieve with conventional materials.

To date, antenna covers have typically been made from polycarbonates (PCs) or similar materials, but this choice leaves much to be desired from the standpoint of dielectric properties. We recommend to use AA181-7 (Developing code name*) for antenna covers which may eliminate such problems.

*Please note that XYRON™ developed material "AA181-7" is only a tentative name at the development stage, and the grade name may change in the future when it is officially commercialized.

XYRON™443Z DH (85℃×85%RH) test 23℃ Charpy impact strength
XYRON™443Z DH (85℃×85%RH) test 23℃ Charpy impact strength

Low yellowing grade 345Z (under development)

XYRON™ low yellowing grade 345Z is a grade that retards weather discoloration while maintaining high flame retardance and impact resistance.
As shown in the figure below, the color difference (ΔE) after weathering test is smaller than that of polycarbonate (PC).

For more information on physical properties and other details, please download slides.

Comparison of ΔE change after weathering test between XYRON™ 345Z and PC

For 5G base-station dielectric property controllable grades xyron Grades with well-controlled dielectric permittivity

The unique low-permittivity properties of PPE, in combination with Asahi Kasei’s compound-material technology, have allowed us to develop new resin grades with well-controlled dielectric permittivity.

Dielectric materials have wavelength-shortening properties, and have found use in a variety of applications, including dielectric phase shifters and antennas, where the use of high-permittivity (high Dk), low-loss (low Df) materials can reduce size and weight of components.

However, conventional materials offer a tradeoff between high Dk and low Df, and achieving both simultaneously is difficult. To achieve both high Dk and low Df in the same material, Asahi Kasei is developing XYRON™ grades with carefully controlled Dk and Df. These resins are ideal for fabricating miniaturized antennas or dielectric phase shifters for use in base stations. 

By proposing dielectric property grades that meet customer needs, we will contribute to the further enhancement of the functionality of next-generation communication base stations.

For more information on physical properties and other details, please download slides.

Wide range of dielectric properties of modified PPE resin XYRON™
Wide range of dielectric properties of modified PPE resin XYRON™

Materials for 5G base-station antenna boards xyron AA222-2 (under development)

XYRON™ under develop material AA222-2 is a PPS/PPE alloy with low dielectric properties and improved flame resistance.

It has a lower specific gravity than PPS, which has been conventionally used for antenna boards (antenna element holders), enabling weight reduction. It also has excellent platability and workability (low warpage and low flash).

For more information on physical properties and other details, please download slides.

5G通信基地局 アンテナボード(アンテナ素子ホルダー)

For 5G base-station RF cavity filters and slotted waveguide array antennas xyron AA105-52(under development)

Asahi Kasei is developing XYRON™ grades for RF cavity filters in 5G base stations.

Base stations commonly incorporate large numbers of metal or ceramic RF filters and slotted waveguide array antennas that increase system weight, complicating installation, and increasing operating losses. The greater density of base stations required for 5G networks makes these factors even more important—and creates an urgent demand for lighter-weight components.

XYRON™ AA105-52(under development) offers high heat resistance, good plating properties, and low linear-expansion coefficients comparable to those of metallic materials, facilitating your transition to resin-based RF filters and slotted waveguide array antennas.

5G基地局 キャビティー型RFフィルター向けザイロン開発グレード

XYRON™ AA105-52(under development) is ideal replacement for metals for reducing the weight of components demanding dimensional stability in a variety of operating temperatures, and a low coefficient of linear thermal expansion over a broad temperature range.。

For more information on physical properties and other details, please download slides.


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