Effects of Various ‘Sight Screen’ Materials on 5G FR2 Transmission

April 17, 2020 Anritsu Company

April 17, 2020

As the first generation of 5G networks are being rolled out, an issue that can’t be overlooked by mobile carriers and installers is the effect of “sight screens” on transmission quality. For years, building landlords in urban areas have required operators to conceal antennas and transmission equipment used in rooftop installations so they are not seen at street level. While these screens caused minimal signal loss in LTE networks, they will have a more profound effect on 5G signals.

Another factor highlighting the importance of selecting the proper screens is that 5G radio deployments will be on more than rooftops. Street lampposts and dedicated poles will be installed in cities and other congested areas. This means the materials used for the sight screens must be properly selected or the 5G radios will transmit less efficiently at a higher power or there will be reduced coverage from each radio. 

Propagation loss due to sight screens will occur in the sub-6 GHz Frequency Range 1 (FR1) band  operating at 3.5 GHz. It is an even greater consideration with Frequency Range (FR2) transmissions since they operate at 28 GHz and 39 GHz. Because FR2 signals travel in the millimeter wave (mmWave) bands, the distance between base stations or small cells needs to be very short to provide reliable wide area coverage. For that reason, 5G FR2 radios in some American urban centers are being deployed every 100 meters. Higher frequencies are also more susceptible to outside factors such as screens.

Figure 1 shows a typical 5G FR2 radio rooftop installation. The radio is barely visible through the cut out in the sight screen being erected to hide the radios from street level. Careful selection of the materials used for this type of environment is essential to ensure optimum network performance. Materials should be accurately characterized for their RF attenuation properties to ensure networks meet key performance indicators (KPIs).

Sight screen installation.
Figure 1: Sight screen installation.

Conducting Materials Measurements

One test tool to conduct these necessary measurements is the Anritsu Microwave Site Master S820E handheld cable and antenna analyzer configured with a waveguide horn antenna. Field engineers and technicians can use this field solution to conduct quantitative insertion loss measurements on a wide range of materials. Based on these results, network planners can model 5G network coverage and select materials that provide the best compromise between durability and aesthetics without sacrificing network coverage and user experience.

The S820E was used to measure the impact common office building materials will have on 5G signals. Results of the tests taken on these materials – drywall, wood paneling, regular and low-E thermopane windows, fiberglass, and office cubicle partition – can be seen in table 1.

Material Tested


Wood Panel

Regular Thermopane

Low E

Fiberglass Insulation (8")

Office Cubicle Partition

Average Loss (dB)







Table 1: Propagation loss of 5G signals based upon common building material.

Let’s look at each measurement in a bit more detail:

Drywall and Wood Panel

Measurement taken with the Site Master antenna analyzer revealed that drywall and wood panels should pose no significant issues with respect to signal loss. Based on the measurement results, FR2 signals are able to propagate well through these materials.

Thermopane Glass

FR2 signals are able to propagate through a standard thermopane window (Figure 2) with little loss. The same can’t be said for the low-E (low-emissivity) thermopane window (Figure 3), which acts as a barrier for the FR2 signals. Low-E glass has a special microscopically thin reflective coating that minimizes the amount of infrared and ultraviolet light – and 5G signals – that enter a building. FR2 signals are not able to propagate through these types of windows.

Standard thermopane window.
Figure 2: Standard thermopane window.
Low-E thermopane window.
Figure 3: Low-E thermopane window.

This will present some significant challenges, since many newer buildings utilize low-E thermopane windows due to their excellent overall energy efficiency. With considerably lower penetration of FR2 signal levels inside the building from 5G gNB external base stations, users may experience dropped calls, an inability to connect to a network, and very slow data speeds. In other words, all of the desired benefits provided by the wide bandwidth available in the FR2 bands will be negated by the high losses caused by the low-E type windows. 

There is also the issue of rain. Measurements indicated that a regular thermopane window created signal loss of ~3 dB. That same window’s loss increased significantly to ~17 dB with water sheeting. This could easily occur when a strong rainstorm with high winds forces the rain to fall angularly onto the glass.

Fiberglass and Office Cubical Partition

Test results indicated that commonly used fiberglass insulation poses no threat to FR2 signals. In contrast, office wall cubicle material is absolutely catastrophic to the FR2 signals, as shown in figure 4. This particular office cubical material would pose significant problems for indoor FR2 signal coverage.

Office cubical partition.
Figure 4: Office cubical partition.

Manufacturers of office cubicle materials will need to investigate using different materials to obtain the desired structural strength of the cubicle partitions while minimizing FR2 propagation loss. Alternative materials will need to be considered with a focus on ensuring negligible propagation losses at FR2 frequency bands.

Canvas Fabric

Dry canvas measurement results were <0.5 dB, making it appear as though canvas fabric is a good choice for concealing antennas and/or 5G base stations. It is easy to work with, durable, and very flexible. Not everything is as it appears, however. If not properly treated to prevent moisture absorption, the canvas material becomes one of the worst possible choices! Its loss increases dramatically once it has absorbed moisture. One layer of wet canvas had ~10 dB of loss (Figures 5a and 5b).

Layer of dry canvas.
Figure 5a: Layer of dry canvas.
Layer of wet canvas.
Figure 5b: Layer of wet canvas.

Consider this. If an antenna system is concealed using very thick and rugged canvas that is equivalent to 4 layers of the sample tested, the insertion loss will be <0.5 dB when dry. After the canvas absorbs moisture, the insertion loss increases to ~40 dB, which makes it likely that a connection can be lost. Dry vs. wet open cell foam exhibited similar characteristics compared with the dry vs. wet canvas. You can watch a video of this effect (and others) that was taken by the testing crew.

An application note, Measuring Path Loss of 5G FR2 Transmissions Through Common Materials Found in the Signal Path, has been published and can be downloaded from the Anritsu website. It provides more insight into selecting proper sight screen materials.

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