Multimode, multiband antennas for MIMO handsets with metal bezel

Recently, we proposed a design framework to obtain efficient and uncorrelated MIMO antennas in mobile handsets for frequencies below 1 GHz. The main benefit of the approach is that it can give significantly larger bandwidths than existing techniques. Using the Theory of Characteristic Modes, it has been shown that slightly modification of the chassis can result in multiple orthogonal resonant modes that may be excited to facilitate low correlation. In addition, multiband operation can be achieved for each antenna by correlating the characteristic currents of different modes across different frequency bands. Here, we utilize the proposed approach to make opportunistic use of the bezel structure popular i n mobile handset designs to achieve efficient and uncorrelated multiband MIMO antennas.