Antenna is indispensable in wireless communications. An antenna array is well known for its power in harnessing spatially distributed radio energy for more reliable data reception. The current smart antenna technology has taken advantage of the theories of phased antenna arrays, adaptive beamformers, and optimal array processing [1]. These theories have been developed and refined in the past several decades. More recent trends in antenna arrays include blind channel estimation and equalization,

more »

... and space-time coding for multiple transmitters and/or multiple receivers [2], [3] . These new trends primarily focus on the needs in mobile environments where fast channel fadings are predominant in limiting channel capacities.