Novel and Efficient Parasitic Decoupling Network for Closely Coupled Antennas

Abstract

A novel and efficient parasitic decoupling network (PDN) is proposed for closely coupled antennas in this paper, which provides a new perspective and approach to design DNs based on the parasitic decoupling concept. The PDN is composed of sections of transmission lines (TLs) and reactive components, allowing additional power-traveling paths. With the TL lengths and reactive-component reactances being precisely determined, the traveling power from one antenna to another could cancel out the undesired power wave induced by mutual coupling, resulting in the high port isolation. The decoupling theory is rigorously derived with the design procedure of the PDN systematically described in connection with two examples of the two- and three-element monopole arrays. The measurement results show that good impedance matching for each antenna port, isolations of more than 25 dB, total efficiencies of more than 64%, and envelop correlation coefficients (ECCs) of less than 0.07 are attained simultaneously for both examples using the proposed PDN. The results verified the decoupling theory and proved the PDN concept.