Multiband and Wideband Self-Multipath Decoupled Antenna Pairs

We propose a series of closely spaced self-multipath decoupled antenna pairs that are capable of realizing self-decoupling performance from a single band to four bands for 5G mobile terminals. First, we propose a self-multipath counteraction method by building multiple coupling paths on the radiating branch of one of the antennas, where the coupling energy passing through the multiple coupling paths could be counteracted at the feeding ports. Based on this principle, two types of single-band self-multipath decoupled antenna pairs are constructed with the shorted end and the open end without using any additional decoupling structures. Then, a dual-band and wideband self-multipath decoupled antenna pair is designed by combining the multipath of such two types of single-band self-multipath decoupled antenna pairs. Finally, a four-band and wideband self-multipath decoupled antenna pair is constructed to further widen the decoupling bandwidth based on the dual-band self-multipath decoupled antenna pair. Both simulated and measured results show that the four-band antenna pair can be self-decoupled at four bands with the isolation more than 20 dB over entire N77, N78, and N79 bands, demonstrating excellent multiband and wideband self-decoupling performance. The proposed self-multipath counteraction method, with the merits of simple antenna structure and wideband self-decoupling performance, should provide significant application values for the very compact and wideband multiple-input multiple-output (MIMO) systems.