Low dielectric constant materials for 5G 5G
- Key features of 5G networks include (1) ultra-high speeds, (2) ultra-low delays, and (3) large numbers of simultaneous connections.
- 5G networks use high-frequency electromagnetic signals that are highly susceptible to attenuation, making large transmission losses a problem. Addressing this issue requires rethinking the materials used to construct network hardware components.
- Asahi Kasei recommends our XYRONTM modified polyphenylene ether resins as materials for 5G network components, including smartphone and base stations.
The evolution of mobile networks and the road to 5G
Mobile networks have evolved in tandem with progress in cellular device technology and the explosive growth in data-transmission volumes.
The field began with the first generation (1G) of analog wireless networks in the 1980s, which made possible the first mobile voice conversations.
The transition to digital networking proceeded through the 2G networks of the 1990s, an era in which the use of mobile data services—driven primarily by e-mail—became widespread.
In the 2000s, 3G networks enabled a dramatic increase in data speeds, allowing sharing of static images and birthing the first mobile web browsers; it was during this time that globally standardized digital protocols were adopted as networking standards.
The 2010s saw the emergence of smartphones, which became increasingly ubiquitous together with 3.9G long-term evolution (LTE) networks. Meanwhile, since 2015 the LTE Advanced standard has enabled a broad rollout of 4G networks —a trend that continues to the present day.
The hotly anticipated next step in the evolution of communication standards is 5G networking, whose rollout is currently underway.
Features and challenges of 5G networks
The three most important advantages of 5G networks are as follows.
Advantages of 5G networks
- eMBB (enhanced Mobile Broadband): Ultra-high speed, high-volume communication
- URLLC (Ultra-Reliable and Low Latency Communications): Ultra-high reliability and low delay
- mMTC (massive Machine Type Communication): Large numbers of simultaneous connections
5G networks are expected to offer maximum data-transmission speeds at least 10 times greater than those of 4G networks.*1
5G networks use higher-frequency electromagnetic signals than previous network generations. In Japan, for example, 4G networks use frequencies in the platinum band (700-900 MHz) or the primary band (1.5-3.5 GHz), while 5G networks primarily use the Sub6 (3.7, 4.5 GHz) and quasi-millimeter (28 GHz) bands. The use of higher-frequency signals comes at some cost: the attenuation of electromagnetic signals is proportional to the frequency squared*2, so high-frequency signals suffer much greater losses than low-frequency signals—and greater difficulty in reaching their intended destination. This poses challenges for network connectivity, and can serve as an obstacle to ensuring reliable communications.
For this reason, 5G networks require more base stations than previous generations, and 5G smartphone terminals must incorporate higher-performance radio systems to ensure satisfactory communications.
*1: 5G networks offer data transmission at rates of 10 Gbps, compared to 1 Gbps for 4G networks.
*2: Friis transmission equation
Performance requirements for 5G network components
The nature of 5G networking requires that hardware devices be designed to minimize attenuation of high-frequency electromagnetic signals.
This, in turn, demands that the components of these devices be made from materials with low relative dielectric permittivity and a low loss tangent. The relative dielectric permittivity and loss tangent of a material are physical properties that control the attenuation of electromagnetic signals in the material; materials with high permittivity or high loss tend to absorb electromagnetic signals, increasing signal losses and degrading communication sensitivity.
The specific challenges of 5G networking demand new levels of ingenuity in designing network hardware, including minimizing electromagnetic signal attenuation in the cases or chassis in which hardware components are enclosed and optimizing the layout of those components to further reduce electromagnetic interference.
Achieving high reception sensitivity in 5G networks requires nothing less than a comprehensive approach in which the design of each individual component is optimized for maximal performance.
Smartphone users tend to prefer devices with slim cases, and the challenge of squeezing components into the thinnest possible case is a key aspect of smartphone terminal design. To this end, terminal designers have pursued a variety of miniaturization strategies, including: careful selection of materials for cases, frames, and antennas; designs that eliminate interconnect wiring; modularization of various components; and flexible printed circuit boards.
For base stations, signal attenuation in the materials used for cases and antenna components is just as important a consideration as it is for mobile terminals. And in order to transmit electromagnetic-signal transmission more efficiently, the relative permittivity and dielectric loss tangent must be controlled to adapt to the component and its location.
Also, base stations incorporate large numbers of metal or ceramic filters that increase system weight, increasing person-hour and workload required for installation ; the more base stations required for 5G networks ensures that weight of a base station make non-negligible contributions to operating losses and cost.
For these reasons, in addition to controlling material relative dielectric permittivity and loss tangents, switching to resin-based materials for covers, cases, filters, and antennas can facilitate 5G network infrastructure by reducing system weight and systematizing components of complicated shapes.
Asahi Kasei’s Recommended Solutions
XYRON™ for 5G networking
Asahi Kasei recommends the XYRON™ modified polyphenylene ether (PPE) resins as materials for 5G network components, including smartphone terminals and base stations.
What is XYRON™?
Asahi Kasei’s XYRONTM is polymer alloy combining polyphenylene ether (PPE) with other resins. The XYRONTM 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.
XYRONTM offers multiple excellent physical properties. In addition to their high heat resistance, they boast excellent flame retardance and electrical insulation, dimensional stability, 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.
To date, XYRONTM has been used to make components and cases for a wide range of industrial sectors, from automobiles to household appliances. For automobiles, in particular, the combination of low specific gravity with high heat resistance and flame retardance has made the use of XYRONTM a popular strategy for reducing the weight of on-board components.
Why choose XYRON™?
The parent material of all XYRONTM products is polyphenylene ether (PPE), whose low dielectric permittivity and low loss tangent make it well-suited for use in information and communications field. 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.
Dielectric properties of various materials
XYRONTM combines the low dielectric permittivity of PPE with Asahi Kasei’s compound technology to accommodate a broad spectrum of requirements regarding dielectric properties, as represented by the extensive lineup of XYRONTM grades featuring various dielectric properties.
Dielectric properties of XYRON™ grades (at 10 GHz)
Recycled PET/PPE alloys for 5G smartphone terminal chassis
In keeping with our commitment to develop innovative materials for sustainable societies, Asahi Kasei is proud to introduce a new addition to our XYRON™ family of modified polyphenylene-ether resins: recycled PET/PPE alloys for 5G smartphone terminal chassis, especially for US, India and Japan market*.
Asahi Kasei is working to develop recycled XYRON™ grades that combine PPE with various recycled resins to yield sustainable manufacturing without sacrificing the high performance of these unique materials.
XYRON™ recycled PET/PPE alloys use approximately 40% post-consumer recycled resins—recovered from PET bottles and other items—while retaining the good mechanical properties and low dielectric properties (low dielectric permittivity and low loss tangent) of conventional XYRON™ grades.
These resins, which allow bonding to metals, are ideal for use as advanced chassis materials for smartphone terminals: not only are they derived from recycled products, but they also a boast lower dielectric properties than currently used PBT+GF materials. This material can be applied to chassis for tablets, laptop or note PC.
*Note: For other regions, please contact with your Asahi Kasei sales representative.
MID antennas for 5G-compliant smartphones
Asahi Kasei is developing XYRONTM grades for use as materials for MID antennas in 5G-compliant smartphones.
The outstanding properties of these grades include their low dielectric permittivity, low loss tangent, and high hydrolysis resistance. Simulation results indicate that the use of these materials in MID antennas can improve total efficiency by as much as 1 dB compared to the polycarbonate (PC) materials conventionally used for this purpose.
We offer to use this material which may enable operation at higher frequencies and more advanced device functionality, alleviating design space constraints to facilitate your development process.
Results of total-efficiency simulatios for antennas made from XYRON™ grades
Antenna covers for 5G base stations
AA181-7(Developing code name*): A XYRON™ material innovation
Asahi Kasei recommends AA181-7 (Developing code name*), XYRONTM developing grade, for antenna covers in 5G base stations.
AA181-7 (Developing code name*)is a XYRONTM developing grade with excellent hydrolysis resistance and shock resistance that is available in all colors and is compliant with the UL94V-0 flame-retardance standard.
Antenna covers—the outermost layers of antenna assemblies—require lightweight, weather-resistant materials with low dielectric permittivity to improve electromagnetic-wave transmissivity. AA181-7 (Developing code name*) simultaneously offers low dielectric permittivity and compliance with the UL94V-0 flame-retardance standard, which is difficult to achieve using 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.
Asahi Kasei is also developing additional XYRONTM grades for various types of equipment covers, including grades that resist color changes induced by light exposure. The XYRONTM family of materials is the right choice to satisfy a wide range of specifications for 5G base-station antenna covers.
*Developing code name is temporary.
RF cavity filters for 5G base stations
Asahi Kasei is developing XYRONTM grades for RF cavity filters in 5G base stations.
Base stations commonly incorporate large numbers of metal or ceramic RF filters 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.
XYRONTM grades for RF filters—specifically designed for applications to RF cavity filters in 5G base stations–offer 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.