Dual-Band Antenna Pair with Lumped Filters for 5G MIMO Terminals

This article proposes a novel design of the dual-band antenna pair. Starting from the single-band antenna pair composed of T-shaped monopole and T-shaped slot that are intersected with each other, orthogonal T-monopole and odd-symmetrical slot modes are excited. By adding symmetrical low-pass high-stop filters into the horizontal stub of the T-monopole and high-pass low-stop filters into the gap of the T-slot, an extra mode is introduced for each antenna, producing dual-band operation. Impedance bandwidths and radiation efficiencies of both bands can be adjusted flexibly using the filters. A detailed design guideline is given. The dual-band antenna pair operating at partial N78 (p-N78, 3.43.6 GHz) and partial N79 (p-N79, 4.84.9 GHz) is with a footprint of $15\times 6$ mm2. The measured results show that the average efficiencies are both -3.4 dB at p-N78/p-N79 for the odd-symmetrical slot and -2.8 dB/-3.7 dB at p-N78/p-N79 for the T-monopole, isolations are better than -16.8 dB at p-N78 and -11.8 dB at p-N79, and ECCs are lower than 0.1 at p-N78 and 0.2 at p-N79. The proposed dual-band antenna pair exhibits great potential to be applied in the fifth-generation (5G) multiple-input multiple-output (MIMO) terminal.