Design of Wideband Decoupling Antenna Pairs for 5G Portable Devices at N77/N78/N79 Bands

We proposed an antenna pair that is applicable for mobile terminals: a type of coupling feed planar antenna that has a size of 28x6 mm(2), a wide band, coupling suppression and compact size. Different from the conventional antenna design, the process of band expansion comes from a dual-band antenna pair and is based on characteristic modes theory (CMA). By observing characteristic current distributions, the optimization emphasis is placed on current sensitive parts in antenna structures, which is an effective method to create or modify resonant points for exciting band potential. Meanwhile, the multiple defective ground structure (DGS) is introduced for isolation enhancement. The -10 dB bandwidth of 3.23-5.24 GHz can be realized, and the isolation of two antenna pairs with only 2 mm spacing is lower (-17.34 dB). The eight-port MIMO system constructed by four proposed antenna pairs has been fabricated. The simulated and measured results of MIMO indicate that its -10 dB operating bandwidth can work at N77/N78/N79/WLAN 5 GHz bands. Moreover, a lower ECC of less than 0.04 and a high efficiency of more than 60% can be obtained, which confirms that it is capable of excellent data transmission as a terminal MIMO antenna system.