Compact, Broadband, and High-Gain Four-Port MIMO Antenna for Future Millimeter Wave Applications

A wideband antenna with a relatively compact size along with a multiple input and multiple output (MIMO) configuration for millimeter wave applications is proposed in this work. The antenna offers a low profile and simple structure. First of all, an antenna is designed using Rogers RT/duroid 6002 (Rogers Corporation, Chandler, AZ, USA) with a thickness of 0.79 mm, offering wideband ranges from 21 to 35 GHz. Subsequently, the unit element is converted into a four-port MIMO antenna to improve the capacity of the system, resulting in a high data rate, which is critical for 5G as well as for devices operating in the mm wave spectrum. The proposed work exhibits total dimensions of 24 × 24 mm² and offers a peak gain of 8.5 dBi, with an efficiency of more than 80%. The MIMO performance parameters are also studied, and the antenna offers exceptional performance in terms of mutual coupling (S_ij) without inserting a decoupling structure, envelop correlation coefficient (ECC), and diversity parameters. The proposed MIMO antenna offers a minimum isolation of -25 dBi and an ECC of less than 0.018. All the other MIMO parameter values lie below the acceptable range. The High Frequency Structure Simulator (HFSS) EM software (v.19) tool is used to analyze the antenna and study its performance. The simulated outcomes are verified by fabricating a prototype, where the result offers a good comparison among both results. Moreover, the contrast in terms of different performance parameters is carried out amongst recent research articles, highlighting the key contribution of the presented design. A compact size antenna with a wideband, simplified structure, and stable performance throughout the working band is achieved; thus, it is a solid contender for mm wave applications and 5G devices.