Design and Analysis of Reconfigurable MIMO Antennas for 5G Wireless Networks

Abstract

The introduction of 5G systems means a sharp increase in the need for antennas supporting ultra-high rates, quick responses and flexible spectrum use, mainly in the millimeter-wave (mmWave) area. This paper details the creation, modeling and evaluation of a Multiple-Input Multiple-Output (MIMO) antenna system for use in 5G mmWave bands. The system uses varactor diodes, RF Micro-Electro-Mechanical Systems (MEMS) switches and Defected Ground Structures (DGS) to make it reconfigurable in both radiation direction and operating frequency. Because of these elements, the system can turn beams regularly and quickly switch frequencies over the 24–30 GHz band for 5G NR bands n257 and n258. The compact Rogers RT/Duroid 5880 was chosen for the design of the antenna array and CST Microwave Studio was used to optimize it for high isolation (>25 dB), low ECC (<0.02) and high radiation efficiency (>85%). Thorough parametric analysis was used to check how performance metrics such as gain, beam overview and coupling decrease due to different reconfiguration mechanisms. Simulation results are confirmed by tests of the prototype which demonstrate that the system can re-tune frequencies, beam in a specific direction (+/- 30°) and always works well in MIMO mode. Because Channel Capacity Loss (CCL) is below 0.3 bps/Hz and Diversity Gain (DG) is above 9.9 dB, the diversity performance is ideal for situations with many users and lots of pathways. The antenna, as described, gives more choices along with a compact design, together with meeting all the requirements expected by next-generation wireless, vehicular and adaptive 5G base station systems. The scalable and low-power benefits of its hybrid approach mean it is a big step forward in the design of 5G and future wireless network antennas.