Compact Dual-Band MIMO Antenna With Shared Decoupling Structure for 5G Mobile Terminals

In this letter, a compact dual-band multiple-input–multiple-output antenna, consisting of four antenna pairs, is presented for fifth-generation mobile terminal applications. Each pair includes two tightly arranged monopoles. By folding the L-shaped monopoles into U-shaped structures, both the 3.5 GHz band and 4.9 GHz band can share the same decoupling inductor. By adding stop-band filter on the monopole, dual-band operation can be provided by a single branch. The size of the dual-band antenna pair is merely 19 × 4 mm². The measured −6 dB bandwidth can cover 3.4–3.6 GHz and 4.8–5.0 GHz, with port isolation higher than 12 dB. The measured radiation efficiency varies from 41% to 59% in the lower band, and varies from 38% to 62% in the upper band.