Researchers Claim 6G Breakthrough
Researchers in Japan have claimed a 6G breakthrough with a demonstration of beamforming in the 300 GHz band, which is expected to be used for 6G.
Developers are looking at using the 300 GHz band for 6G in order to gain a wide frequency range, a press release explains. A key challenge involving that band will be large path loss as signals are propagated through space. Beamforming, which directs the energy of a transmission signal towards a specific target, is viewed as a possible solution.
The demonstration, which was conducted by the Tokyo Institute of Technology and NTT Corp., used a phased-array transmitter module to enable instantaneous ultra-high-capacity data transmission to mobile receivers.
To date, beamforming has only been needed in the 28 GHz and 39 GHz bands – considerably lower frequencies than the 300 GHz frequencies targeted for 6G. The industry is working through two key differences in beamforming between the lower and higher frequency ranges.
The first is that the complementary metal oxide semiconductor-integrated circuits (CMOS-ICs) that have been used to data for beamforming lack the power to successfully operate at 300 GHz. A potential solution is to combine CMOS-ICs with the III-V compound IC semiconductor, which is capable of higher power output.
A secondary problem exists, however: The amount of energy loss inside the III-V compound IC and in the connection between the III-V compound IC and the CMOS-IC has prevented the necessary high output power to be generated, according to NTT.
The research focused on a potential solution. The Tokyo Institute of Technology and NTT developed indium phosphide integrated circuit (InP-IC) chips that integrate the high-output power amplifier circuit and antenna circuit. The platform utilizes NTT’s proprietary indium phosphide-based heterojunction bipolar transistor (InP HBT) technology.
The result of the research, which recently was presented at the 2023 IEEE MTT-S International Microwave Symposium in San Diego, was a compact four-element phased-array transmitter module that put a CMOS-IC and InP-IC on a printed circuit board. It has a steering range of 36 degrees, maximum data rate of 30 Gbps and communications distance of 50 cm, NTT said.