Skip to main content

Futuristic Glass Antenna by NTT Docomo and AGC

For nearly a year, NTT Docomo has been working with the glass manufacturer AGC to create a new transparent antenna that can work with a base station to become an antenna. We know that as we move towards higher frequency, the penetration of radio waves in building is affected. While this is not obvious in C band, it is very visible in case of mmWaves.

In a recent publication titled "An Unobtrusive Antenna", Osamu Sawaji interviewed NTT Docomo and AGC engineers about this development

To solve these problems, NTT DOCOMO entered into joint development with major glass manufacturer AGC, presenting a new glass antenna in November 2018. The antenna is 85 cm wide, 21.2 cm high and 6.6 mm thick, and on first glance appears to be normal transparent glass. However, the antenna becomes a base station when connected to cables and a wireless transceiver in the ceiling and attached to indoor window glass.

The antenna makes use of the laminated glass manufacturing technique used for the front windshield in cars. For laminated glass, resin is put between two sheets of regular glass and melted at high temperature, forming a single piece of glass. The glass antenna is made from the unified transparent resin and conductive materials that are placed between the two sheets of glass. In this way the glass becomes an antenna that can send and receive signals by conducting electricity. 

Moreover, a newly developed Glass Interface Layer (GIL) applied to the surface of the glass antenna reduces the signal attenuation and reflection that normally occurs when passing through window glass. The thickness of window glass varies according to window size and building floor height and normally affects the amount of signal attenuation and reflection, but by selecting the appropriate type of GIL, signals can be sent and received seamlessly no matter the size of the window glass the antenna is installed on.

Plans for commercialization of the glass antenna are now in the works and many inquiries have been received not just from Japanese mobile phone companies but also from companies overseas.

NTT DOCOMO and AGC are investigating the development of a glass antenna compatible with 5G, the next generation system of mobile communications. 5G will enable large amounts of data to be transmitted at very fast speeds, but the 5G signal has the disadvantage of being susceptible to attenuation from buildings, the atmosphere, rain and other obstacles.

NTT Docomo has been working with AGC and Ericsson to show demos of on-glass antennas on windscreen. The playlist for that is embedded below

Back in May, NTT Docomo also announced that they, in partnership with AGC and Ericsson have achieved what is believed to be the world's first 5G mobile telecommunications using an antenna embedded in synthetic fused silica glass to transmit and receive 28 GHz 5G radio signals for stable, high-speed mobile communication in buildings, vehicles and trains.

The antenna was used to verify 28 GHz 5G mobile communication with downlink speeds averaging 1.3 Gbps within a 100-meter range and reaching a maximum of 3.8 Gbps at 400 MHz. The verification tests, which used a vehicle fitted with multiple antennas and traveling about 30 km/h, were conducted in the Sumida area of Tokyo between April 22 and May 28.

Radio signals in the 28 GHz band are more linear than 4G LTE signals, so they are not strong enough to adequately penetrate windows in buildings, vehicles and railway cars. The new glass antenna can be attached to window surfaces to enable radio waves to be received and relayed in ideal directions for stable, high-speed 5G communications under challenging indoor and in-vehicle conditions.

In the latest NTT Docomo Technical Journal (October 2019 - Japanese Version), NTT Docomo have provided more details and trial results of this 5G glass antenna.

As can be seen in the table, in the on-glass antenna experiment using 800MHz bandwidth, A throughput of up to 7.9 Gbps ​​downstream was achieved. The average throughput is 3 Gbps in an area of ​​about 100m radius.The maximum distance was about 232m.

In the experiment with a integrated-glass 5G antenna, a 400MHz bandwidth and an 800MHz bandwidth were used. Up to 3.8Gbps downstream with 400MHz bandwidthwas achieved with 1.3 Gbps on average in an area with a radius of about 100m. Up to 7.5 Gbps downlink with 800 MHz bandwidth was obtained with 2.5 Gbps in an area with a radius of about 100m. The maximum communication distance was 178m.

xoxoxoxoxoxo UPDATED 17 JAN 2020 oxoxoxoxoxoxox
A new article on this topic is available from NTT Docomo in the January 2020 Technical Journal here.

Related Articles:


Popular posts from this blog

Laser Inter-Satellite Links (LISLs) in a Starlink Constellation

When we first talked about Starlink back in 2019 , we saw in the video that the concept involved laser communication to communicate between the satellites. While the initially launched satellites did not have the laser communication mechanism built in, it looks like they are being added to the newer ones.  A report from Fast Company in late 2021 said: One of the next big upgrades in telecom will involve satellites firing lasers at each other—to beam data, not blow stuff up. The upside of replacing traditional radio-frequency communication with lasers, that encode data as pulses of light, can be much like that of deploying fiber-optic cable for terrestrial broadband: much faster speeds and much lower latency. “Laser links in orbit can reduce long-distance latency by as much as 50%, due to higher speed of light in vacuum & shorter path than undersea fiber,” SpaceX founder Elon Musk tweeted in July about the upgrade now beginning for that firm’s Starlink satellite constellation. The

IEEE 802.11bn Ultra High Reliability (UHR), a.k.a. Wi-Fi 8

Back in 2020 we looked at the introductory post of Wi-Fi 7 which was followed up by a more detailed post in Feb 2022. We are now following on with an introductory post on the next generation Wi-Fi.  A new paper on arXiv explores the journey towards IEEE 802.11bn Ultra High Reliability (UHR), the amendment that will form the basis of Wi-Fi 8. Quoting selected items from the paper  below: After providing an overview of the nearly completed Wi-Fi 7 standard, we present new use cases calling for further Wi-Fi evolution. We also outline current standardization, certification, and spectrum allocation activities, sharing updates from the newly formed UHR Study Group. We then introduce the disruptive new features envisioned for Wi-Fi 8 and discuss the associated research challenges. Among those, we focus on access point coordination and demonstrate that it could build upon 802.11be multi-link operation to make Ultra High Reliability a reality in Wi-Fi 8. The IEEE 802.11bn UHR: Whose Study Gro

NTT Docomo's Disaster Countermeasures to Keep People Connected

Recently I blogged about Disaster Roaming in 3GPP Release-17. While this will take time to be implemented worldwide, it is already available in Japan, maybe not in the 3GPP standardised way. Similarly, back in 2011, I blogged about Earthquake and Tsunami Warning service (ETWS) from NTT Docomo's Journal, it was two days before the  2011 Tōhoku earthquake and tsunami hit. Japan is no stranger to earthquakes, typhoons, and other natural disasters, which can have a devastating effect on infrastructure. To ensure that the mobile networks keep functioning, operators work extremely hard to ensure people remain connected one way or another. NTT Docomo has released a video detailing the countermeasures to keep everyone connected in case of emergencies. The following detail is provided with the video: DOCOMO's network is no exception, and our services could get cut off by a base station power outage, disconnected fiber-optic cable, or other malfunctions. DOCOMO established the three pr