We have tried to describe two aspects of MIMO channels: channel capacity and channel modeling. We have analyzed the channel capacity of static and fading MIMO channels when the channel side information is available both at the transmitter and receiver, and when it is available only at the receiver. We have then modeled the MIMO channel in physical and angular domains to understand how it provides spatial multiplexing with the help of degrees of freedom. In physical domain modeling, we have modeled the MIMO channel in terms of individual physical paths. In angular domain modeling, we have described the MIMO channel with respect to fixed spatial basis functions defined by fixed angles that are determined by the spatial resolution of the antenna arrays. All the simulations have been performed on MATLAB 7.4.0.287 (R2007a).

A novel Reconfigurable Coplanar waveguide (CPW) fed T- shaped patch Antenna with frequency diversity is designed and analyzed. The basic antenna consists of two H-shaped patch connected to the radiating element, which is connected with a CPW feed. The reconfigurability in frequency is obtained by connecting MEMS switches in the basic antenna. MEMS switches are used because of their significant RF characteristics, fast switching speed and less power consumption. The switch is connected between the radiating element and the right-hand side H-shaped patch. By controlling (making ON and OFF) the switches, the antenna is made to operate at two different resonant frequencies namely 2.4GHz and 4.4GHz. Hence the antenna is reconfigured to use for two different applications. The designed antenna and simulated results are obtained by using Zeland's Method of Moments based commercial IE3D simulator. The return loss curves, radiation patterns, antenna gain and efficiencies, VSWR curves for different switch configurations are obtained using IE3D software. This antenna is found suitable for wireless communication application such as W-LAN and C-Band applications.