Potential of Polarized MIMO in In-Body to Out-Body Radio Links

Multiple-input multiple-output (MIMO) technology is considered to be a viable method for spectral efficiency and capacity enhancement in wireless communications. This article presents characterization of a polarized MIMO radio channel for wireless capsule endoscopy (WCE) application. A full-wave simulation method for 3-by-3 MIMO systems comprised of three co-located magnetic loops is presented. Furthermore, channel normalized eigenvalues and capacity are derived from channel matrices simulated at five different locations inside a realistic human body model. The results show that the second and third eigenvalue of the channel matrix contribute to the overall channel performance given the practical transmit power constraints of WCE links. Furthermore, using polarized MIMO increases the channel capacity compared to single-input single-output (SISO) counterpart at the same in-body source and on-body receive locations.