Novel dual-band decoupling network for two-element closely spaced L-shape antenna array

An innovative dual-band decoupling network for two-element closely spaced L-shape antenna array is proposed for MIMO applications. The new architecture, combining the reactive element decoupling technique and the eigenmode decoupling approach, provides dual-band decoupling capability with good radiation characteristics. The core building block is a unique dual-mode four-port network; it functions as a conventional 180° hybrid coupler in one frequency band but is equivalent to a pair of isolated direct-thru transmission lines in the other band. The design concept, circuit topology and experimentally results will be discussed in this paper.