NTT DoCoMo preps for 5G with multi-element antenna

NTT DoCoMo showed off its multi-element antenna/circuit integration technology for 5G, and this time, the company revealed an ultrathin filter.

The filter is 8.8 mm long, 0.64 mm thick and 38 mL in volume; it's designed for 15 GHz-band multi-element antennas, according to Nikkei Technology. The service provider exhibited the technology at a DoCoMo R&D open house on Nov. 28.

NTT DoCoMo has been developing elemental technologies with the goal of providing the 5G service in or after 2020. That's the time frame most industry experts are targeting for commercialized 5G, though Huawei has set an ambitious target to conduct a 5G trial with MegaFon during the FIFA World Cup in 2018.

DoCoMo's 5G system is expected to be deployed with a high-frequency band (6 GHz or higher) and massive MIMO, which uses a super-multi-element antenna for beam forming, Nikkei Technology reports. The super-multi-element antenna must be designed so that it can be installed pretty much anywhere, such as on ceilings and walls.

The service provider is working on hardware equipped with a large number of antennas on one side and filters, amplifiers, baseband processing circuit and more on the other side. Because of the large number of antennas, it's necessary to increase the number of filters and amplifiers as well.

DoCoMo reduced the size of the filter with its manufacturing method through holes that are made in a dielectric material with a laser-beam machine. Conductive material is then put in them to realize the desired structure. "Because of the simple manufacturing method, it can be produced in volume at low cost," the company said.

DoCoMo is developing the filter for 15 GHz antennas but has already confirmed that the same manufacturing method can be applied to a filter designed for up to about 20 GHz antennas, the report said.

Earlier this year, DoCoMo released a white paper regarding the 5G network it intends to commercially launch in 2020 in time for the opening of the Summer Olympic and Paralympic Games in Tokyo. In the paper, DoCoMo lays out its views on the technical requirements, evolution concept and candidate technologies for 5G radio access.

For more:
- see this Nikkei Technology article

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