A compact 4-port asymmetric open-slot MIMO antenna for smartwatch-integrated Wi-Fi applications

Abstract Our work introduced a miniaturized 4-port MIMO antenna developed for Wi-Fi band operations, offering enhanced isolation and diversity characteristics. The antenna is fabricated on an FR4 substrate with compact dimensions of $$40 \times 40 \times 0.8\,\text {mm}^3$$ , and inter-element coupling is reduced using an asymmetric element configuration combined with a defected ground structure (DGS), achieving an isolation level of approximately $$-20$$ dB across the 5.15-5.85 GHz frequency range. The diversity performance is measured by key parameters. The envelope correlation coefficient (ECC) is held around 0.01, which indicates minimal correlation between antenna elements. Besides, a diversity gain (DG) of about 9.999 dB was obtained. The channel capacity loss is less than 0.4 bits/s/Hz, which is proving effective data transmission. And the mean effective gain (MEG) is figured to be below $$-3$$ dB, which is good for balanced signal reception in all ports. Also, antenna possesses a peak gain of about 2.9 dBi along with stable radiation features over the entire working band. The measured data is very good alignment with the simulated data, proving that the proposed design is well suited for compact and high performance wireless communication applications.