Photo/IllutrationA mobile antenna made of transparent material jointly developed by NTT Docomo Inc. and glass maker AGC Inc. (Shinya Tokushima)

NTT Docomo Inc. and glass maker AGC Inc. have jointly developed a transparent antenna that can be affixed to the inside of a window without spoiling the view.

The world-first high-tech antenna is expected to be used in urban areas that require numerous base stations, which transmit mobile phone radio waves, to handle high levels of mobile traffic, the companies said Nov. 7.

The transparent antenna featuring new technology fits between two panes of glass and measures 21 centimeters by 70 cm. It allows mobile phone users to communicate without disruption within a radius of 200 meters or so.

The base station equipment is likely to be installed in areas such as just above the ceiling of a room.

The innovation comes amid a rise in mobile traffic in tandem with the spread of smartphones, requiring stable high-speed communication.

In areas with high mobile traffic, it is essential to disperse the radio waves by setting up so-called small-cell antenna base stations, which require additional antennas.

To maintain high-speed communication, Docomo has increased the number of small-scale base stations, especially in highly populated urban areas.

Currently, small antennas are mainly set up outdoors, such as on the rooftop of a building, or on the wall of the lower and middle levels of buildings. However, it is difficult to secure locations for such set-ups and they can spoil a building's appearance.

NTT and AGC plan to start installing the antennas at base stations shortly.

The companies also aim to utilize the antenna for 5G, the next generation of cellular networking that is expected to be put into practical use by 2020.