Abstract—This paper proposes an annular-ring microstrip
antenna for a 2×2 MIMO communication system. A single
annular-ring microstrip antenna with two feed probes is used to
generate two orthogonal radiation patterns. Radiation pattern
associated with each probe is generated by FEKO simulations
and shown that the patterns are orthogonal to each other.
Orthogonal radiation patterns are needed to exploit pattern
diversity instead of space diversity. Miniaturization is achieved
by using a ferrite substrate instead of using a pure dielectric
substrate. A ferrite annular-ring antenna with a single feed probe
was manufactured and tested. Also a ferrite single circular patch
antenna was manufactured and measurement results are
presented.