Multiplexing Antenna System in the Non-Far Region Exploiting Two-dimensional Beam Mode Orthogonality in the Rectangular Coordinate System

A multiplexing antenna system is proposed for high data rate wireless transmission applications in the non-far region. The system is composed of two identical flat rectangular antennas directed toward each other and separated by a distance. Each antenna radiates four beam modes with 2-D orthogonality in the rectangular coordinate system by means of a passive and low-loss beam forming network. Thanks to the orthogonality relation among the modes up to four independent channels in the same direction with the same frequency and polarization can be carried and the signal demultiplexing is facilitated in the reception side. To validate the proposed concepts, the antennas have been designed and fabricated in the E-band around 78.5 GHz. Based on that, the multiplexing system has been experimentally tested. Good agreement between simulations and measurements has been obtained.