MIMO communications system for future applications gradually requires more capacity for the informational contents extension and qualitative improvement. The performance degradation of mobile and wireless systems in a multipath propagation environment, called signal fading phenomenon, can be handled successfully with spatial, polarization, pattern or another diversity schemes. In communications systems, most theories deal with point source analysis for isotropic radiations or simple linear antenna array for co-polarization transmitting and receiving, even analyze two-dimensional models. But, we need to consider the three-dimensional models for realistic multiple scattering environments and also deal with environmental factors which are vertical and horizontal polarization propagation characteristics with cross polarization discriminations (XPD) for realistic multipath channel environments. Thereby, many researches are achieved for exact channel analysis and efforts to expand channels or improve communications performance.
Dipoles or monopoles for linear antennas are frequently used for analyzing the antenna diversity. The polarization diversity was principally developed using orthogonal linear antennas by vertically polarized mobiles with XPDs of incident fields. And even experiments using spatial, polarization and pattern diversity were conducted by using dipoles. Two vertically polarized dipoles or monopoles on the ground are frequently demonstrated with mutual coupling effects with variation of spatial separation between antennas for antenna diversity. True polarization diversity (TPD) is proposed to achieve a high diversity gain by inclined dipole array to receive various polarized waves by multipath fading channel.
The analysis of an antenna mutual coupling is a significant issue for designing the wireless communication system especially related to the antenna diversity problem. The accurate analysis of the mutual coupling between antennas is certainly n...