Enhancement of the frequency characteristics of a decoupling and matching feeding network for a MIMO antenna

In order to enhance the bandwidth of the radiation efficiency of a MIMO antenna using a decoupling and matching feeding network, a new design formula of the DMFN elements which can match the antenna conductance to the terminal loads with different value. The unitary matrix in the design formula of the DMFN, which can equalize the bandwidth of each feeding terminal has been derived. It has been also evaluated how the imaginary part of the antenna admittance affect to the bandwidth of the radiation efficiency.