Abstract
We proposed an analog eigenmode transmission technique, that realizes multi-stream parallel transmission in a short-range multiple-input multiple-output (SR-MIMO) communication using only 180-degree hybrid couplers. Provided the MIMO array is symmetric, this technique can orthogonalize MIMO channels independently of antenna spacing and Tx-Rx distance. Furthermore, due to wideband characteristics of a hybrid, the channel orthogonalization effect can hold over a broad band of frequencies. In this letter, its array parameter independency and wideband characteristics are quantitatively evaluated in term of channel capacity. It has been experimentally clarified that this technique achieves approximately 90-% performance of ideal eigenbeam space division multiplexing (E-SDM) by digital-beamforming despite the deviations of the above factors.
