Small-Size 6-Port Antenna for Three-Dimensional Multipath Wireless Channels

We discuss the issues of designing small-size antennas for multiple-input multiple-output (MIMO) communication systems. Introduction of the notion "potential antenna" facilitates antenna performance estimations to a great extent. Potential antenna is an idealized perfect antenna capable of absorbing the absolute entirety of information from the electromagnetic field present in a given region of space. The potential antenna concept proves instrumental in demonstrating that the optimal number of spatial subchannels for a small-size receive region in a three-dimensional (3-D) omnidirectional channel is 6. We present a compact 6-port receive antenna for 3-D wireless channels. Evidence is given to show that the suggested antenna assures a channel capacity that approximates to the theoretical limit thus making the antenna fit for use in high data rate mobile MIMO systems