In February 2024, Professor Kenichi Okada of the Department of Electrical and Electronic Engineering, Tokyo Institute of Technology, and a research group from Nippon Telegraph and Telephone (NTT) announced that they would be able to realize a 300GHz band phased array transmitter using CMOS integrated circuits, including the antenna and power amplifier. announced that it was a success. It demonstrated the transmission rate of over 100 Gbit/s, which is expected in 6G (sixth generation mobile communications).
The newly developed 300GHz phased array transmitter was designed using a 65nm silicon CMOS process. In order to create a CMOS power amplifier that operates in the 300GHz band, we optimized the transistor placement. As a result, the parasitic resistance/capacitance has been reduced, and the gain in the 250G to 300GHz band has been significantly improved compared to conventional products.
We developed an amplifier using the developed transistor. This amplifier achieved a gain of more than 20dB from 237 to 267GHz, and a saturation output power of -3.4dBm at 251GHz. When we measured the noise figure, we found that it was 15dB. The transmitter IC has an “amplifier last” configuration in which the final stage is an amplifier that directly drives the on-chip antenna. In addition, by devising the configuration of the LO circuit, which includes a subharmonic mixer, phase shifter, and quadruple multiplier, the area has been reduced to one-fifth of the conventional size. Four transmission circuits are integrated into a chip size of 3.8 x 2.6 mm.
Source: Monoist
https://eetimes.itmedia.co.jp/ee/articles/2402/20/news054.html
