High efficient graphene-based antenna for monoliinthically integrating with transistors

抄録

Toward Society 5.0, next generation wireless communication (Beyond 5G) is indispensable as the infrastructure. 70 trillion Beyond 5G devices are needed and contain high environmental elements, such as In, As, and Cu. The realization of Society 5.0 will threaten global environment. Therefore, for realizing Beyond 5G, we should create Beyond 5G devices with low-environmental cost. We proposed a novel monolithically integrated devices on SiC consisting of graphene based antenna and GaN based high electron mobility transistor (GaN-HEMT) (Patent application number 2021 207486). As the first step, we are developing an antenna using graphene grown on SiC for the purpose of the monolithic integration.

We will present the study on the graphene based antenna on SiC (Fig. 1). The antenna consists of a coplanar waveguide (CPW) and antenna elements. The characteristic impedance Z0 of the CPW was matched to the characteristic impedance of the measurement system (50 ohm) to minimize return loss. The structure-dependence of the characteristic impedance was investigated and succeeded in optimizing the structure to set 50 ohm. The return loss (RL) and transmission power efficiency of this CPW from 300 kHz to 9 GHz showed that RL is below -37.3 dB and transmission power efficiency 99.97%. This means that a very low-loss CPW was fabricated. In addition, this is the first successful fabrication of the graphene antenna on SiC resonating at 40.7 GHz by using the scattering (S) parameter measurement for high-frequnecy electrical measurement. The transmission power efficiency was measured to be 97.19%. The transmission power efficiency at the resonant frequency is 90% in the previous report. Our antenna is more efficient by 7%, compared to that in the previous report. Our work demonstrates the capability of the graphene antenna on SiC as the highly efficient antenna for Beyond 5G.