Experimental Verification on LoS-MIMO Transmission in 300-GHz Band

In this study, we conducted Line-of-Sight (LoS) 2x2 multiple-input multiple-output (MIMO) orthogonal frequencydivision multiplexing (OFDM) transmission experiments in the 300-GHz band to investigate the potential for channel capacity enhancement. A circularly polarized patch antenna, supporting both crossand co-polarization, and a 2x2 MIMO transceiver equipped with a Pre-Correction scheme were developed. Experimental evaluation was carried out under conditions of a stream spacing of 0.3 m and a transmission distance of 1.9 m. As a result, in both coand cross-polarized antenna configurations, the off-diagonal components were suppressed below -20 dB, and 2-stream transmission with 16-QAM modulation achieved a throughput of 13.1 Gbit/s and a spectral efficiency of 6.55 bit/s/Hz. Furthermore, future research directions toward advanced spatial multiplexing based on channel correlation analysis are discussed. These results demonstrate the feasibility of highcapacity fixed wireless links and provide practical design insights for long-distance transmission.