Analysis of path loss and channel capacity in quad element MIMO antenna for terahertz communication systems

A quad element multiple-input-multiple-output (MIMO) antenna with improved impedance bandwidth of 0.126 THz (0.198–0.324 THz) by using defected ground structure (DGS) is proposed for terahertz applications. The four elements are placed orthogonally to one another to reduce mutual coupling and envelope correlation coefficient (ECC). The maximum isolation of the proposed MIMO antenna is 34 dB at 0.290 THz frequency. The diversity performance characteristics of the proposed antenna are studied in terms of ECC, diversity gain (DG), mean effective gain (MEG), total active reflection coefficient (TARC), and isolation between the ports, and the obtained values are 0.05, 9.9, (Formula presented.) 3, −5, −10, respectively. Each antenna has a peak gain of 4.4 dBi with an average radiation efficiency of 92.5%. The proposed MIMO antenna is designed on a Rogers RO4003 substrate having a dielectric constant of 3.55, and a loss tangent of 0.0027 with a dimension of (Formula presented.) (Formula presented.) m³. Further analyses of path loss in free space, atmospheric absorption, and roughness factor in indoor surfaces for THz communication are also studied. The designed MIMO antenna is suitable for high-speed short distance communication, video-rate imaging, biomedical imaging, sensing, and security scanning in the THz frequency band.