A Dual-Band PIFA for MIMO Half-duplex 4G and Future Full-Duplex 5G communication for Mobile Handsets

This paper studies the design of a 4G/LTE and 5G antenna system dedicated to mobile terminals (MTs). Achievingthis target can’t be detached from the fact of multimode functionality when designing antenna systems for MTs. Moreover, in line with the advantages covered by 5G over previous generations, it is good thinking that 5G acquires the fullduplex (FD) feature, which needs, in turn, multiple antennas. But, the design of multiple antennas in compact MTs is a significant challenge, due to both practical and fundamental design tradeoffs. In this paper, multimode mobile antenna system dedicated to FD 5G and Multi-Input-Multi-Output (MIMO) half duplex (HD) 4G applications are designed and studied. The results reveal that it is possible to achieve an efficient multimode antenna system when paying attention to some designing rules during the progress of the study. To demonstrate the effectiveness of the proposed approach, a dual-band Planar Inverted F – Antenna (PIFA) dedicated to MTs was first designed. Based on the obtained results, a double antenna structure, made up of two dual-band PIFA was then proposed. The two antennas terminal provides an isolation of over 20 dB for the 2.6 GHz band and over 35 dB for 3.6 GHz band without additional matching or decoupling structures. A trade-off analysis of bandwidth and efficiency is performed over different antenna locations and configurations. Finally, two fabricated prototypes verify the simulation results for representative cases.