Abstract: In this Paper we design two- element MIMO antennas and various isolation structures and mechanisms to reduce the mutual coupling between the two elements, out of which two major antenna designs are proposed and analyzed separately for their isolation, bandwidth and radiation characteristics. The MIMO antenna system consists of two semicircular radiating elements on a single low-cost FR4 substrate of a compact size of 35 mm 40 mm and is fed by a 50-? microstrip line. A T- shaped slot is etched on the radiating elements to enhance the impedance bandwidth. The proposed antenna system operates over a wide frequency range from 4.4 to 10.7 GHz. A fork-shaped structure is introduced in the ground plane to increase the isolation between the antennas. Simulated results of S-parameters of the proposed antenna system are obtained and a high isolation of -20 dB is achieved in most of the band, which is found suitable for MIMO applications.

Keywords: MIMO, S-Parameter, isolation, coupling etc.