What is a 5G network? The short answer is: Nobody really knows, yet. The fifth generation of wireless communications remains a work in progress. As Stephen Lawson wrote in October 2015 in his ComputerWorld article, “FCC Looks to Higher Frequencies for 5G Mobile,” there are many unknowns, including solutions for spectrum-sharing, potential service rules for 5G radio-frequency bands, which bands will be useful, ownership of these frequencies, band-sharing and coexistence with current services, and so on. These are all obstacles that specialists are working through, which explains why, in 2015 in its report, “5G Spectrum Recommendations,” 4G Americas said it could take about five years for 5G to arrive.
But when it comes to concealment, we’re already prepared to debunk the rumors about 5G. Not only will concealment be critical in 5G deployment, it should be considered sooner rather than later.
Previous advancements in technology from 1G to 3G brought massive changes. 1G brought cell phones; 2G brought texting; and slowly but surely, our lives were taken over with the ability to access the Internet from anywhere with 3G. The details appear in “Everything You Need To Know About 5G” by Amy Nordrum, Kristen Clark and the IEEE Spectrum staff, published on Jan. 27, 2017, in IEEE Spectrum.
OK, maybe the part about 3G is a bit dramatic, but ultimately, our lives have changed considerably. With 4G, the consumer technology is generally the same as 3G, just significantly faster. Speeds and functionalities have increased with each technology, but with 5G, we’re going to experience advancements with capabilities the like of which we’ve never seen before. Incredible functionality, including 4K and 8K video, augmented and virtual reality, and autonomous vehicle support are among the advances that 5G makes possible (see Figure 1).
Today’s 4G systems link user devices on frequencies as high as 2.5GHz and use higher frequencies on a small percentage of sites for backhaul. 5G technologies, however, are expected to rely heavily on higher-frequency signals that are desirable because they can carry immense amounts of data to support the breathtaking new functionalities previously mentioned. In fact, as shown in Figure 2, the use of higher-frequency
signals (commonly referred to as millimeter waves) will provide more room to grow, potentially allowing 1,000 times more traffic; that is 10 times faster than our current 4G LTE. These same higher frequencies that will enable the 5G revolution will also create substantial new concealment challenges for antennas and equipment. Testing is in progress in the 28-GHz, 37-GHz, 39-GHz and 64-GHz to 71-GHz bands for use in the United States, according to 4G Americas. In general, these higher frequency applications are much more sensitive to concealment materials placed in the antenna path. The good news? Some concealment materials and material combinations work well at the frequencies being considered; however, there is no one silver-bullet concealment panel. Instead, the correct concealment panel or combination of panels has to be selected based on the concealment application and the frequency or several frequencies being used for the site.
Panel Performance by Frequency
One example is shown in Figure 3. This data represents the volatility in concealment panel performance at different frequencies. The StealthSkin V (SSV) concealment performs well at 2.5 GHz, 5 GHz and 39 GHz, but it shows substantially more loss at 11 GHz and 28 GHz. In addition, the angle of incidence is shown to have a large influence on the amount of expected loss. The data at 28 GHz shows less than 1 dB of loss for a 0-degree angle of incidence, but substantially more when the signal is rotated to 30 degrees relative to the concealment panel.
Application of the concealment product, the color, the material and where the site is located all play a large role on whether or not you will have the best performance possible. For instance, in some cases, fiberglass is more thermally stable than a plastic material, which makes it a good choice for desert climates, but there may be trade-offs in RF performance. Different panel options are not suitable for certain environments, depending on the temperature and the exposure to elements. Some thin plastic materials are excellent performers at a variety of frequencies. But because of their relatively low strength, they may not be usable for larger screen-wall types of concealment applications. The best concealment for your project should be decided on a case-by-case basis. On each site, designers should compare high-frequency applications to ensure that the best possible application and materials are chosen.
It is also important to consider geometry of the antenna signal relative to the concealment material. For most cases, orienting the signal to transmit through the concealment panel in a perpendicular orientation creates the best performance — but not always. The best performance highly depends on the actual frequency being used and the material type and thickness. Signal polarization also should be accounted for. The difference between vertical and horizontal polarization may cause a problem similar to the angle of orientation. The degree and orientation of the wave can have major effects on loss in higher frequencies as the radio wave passes through the concealment panels. We have testing procedures for horizontal and vertical polarizations at 0-degree (perpendicular) and 30-degree angles of incidence for all of the concealment materials we commonly use.
Texture should also be considered as a factor. As shown in Figure 4, a stucco SSV concealment panel and a smooth SSV panel will both experience minimal dB loss at the lower (2.5-GHz) frequency. However, at 39 GHz, the additional loss from the stucco panel is substantial.
As a general rule, higher frequencies are much more sensitive to concealment and other environmental factors than lower frequencies. Many of the proposed frequency ranges will struggle to perform through many commonly used concealment materials now available, but we are thinking ahead. Our materials are not only made to stand the test of time, but to perform at the higher frequency ranges that 5G will require. There are a few things to note, however. If 3G or 4G antennas are swapped out with a new 5G antenna behind existing concealments, the results may be poor. Basically, older and existing concealments may not function with the new 5G frequencies.
No one-size-fits-all concealment product works optimally for all frequencies. For a site to perform at top level through concealment, the materials must be selected for the specific frequency or several frequencies being used. It is important to choose a concealment partner who is prepared for this next step.
Stealth Concealment Solutions has a huge advantage when it comes to 5G. Our RF-transparent materials are proven to stand the test of time, to outperform any other in the industry and to be of the highest quality. We have 4G under control at this point, but we know that 5G will be a whole new ballgame, so we’ve put ourselves to the test, as should all concealment vendors. We have full testing up to 100 GHz on the concealment materials we currently use. This testing gives us the ability to handpick the best possible material based on the frequency used and the concealment application or design required per site. We’ve completed projects in every market and on every application and guarantee that our custom solutions will continue to support sites into the next generation.
Our company’s products cover the wireless industry with rooftop, tower, pole, DAS and many custom concealment structures. Stealth Concealment Solutions’ engineered solid, sound and attractive cell tower concealments accelerate the approval process, and every concealment is engineered using the highest-grade RF-transparent materials available.
Trey Nemeth is vice president of operations at Stealth Concealment Solutions, North Charleston, South Carolina. For more information, visit www.stealthconcealment.com.