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This paper introduces a novel MIMO UWB antenna with dual notches. The proposed antenna is based on Quasi Self Complementary (QSC) method to give wide impedance bandwidth from 2.4 GHz to more than 12 GHz. The proposed antenna consists of a semi-elliptical patch that is fed by a tapered microstrip line. The antenna is designed on an FR-4 substrate with compact size 20 mm × 15 mm × 1.5 mm. The dual notched bands are achieved by using a square ring printed on the bottom of the substrate to reject WiMAX at 3.6 GHz. Also, a C-shaped slot is etched in the radiating patch to reject interference with the WLAN band at 5.8 GHz. In the proposed MIMO antenna, the isolation reduction is achieved utilizing diversity technique to minimize the mutual coupling between the antennas. The isolation between MIMO elements is more than 20 dB. The envelope correlation coefficient (ECC), diversity gain (DG), total active reflection coefficient (TARC), furthermore, channel capacity loss (CCL) are measured and calculated. The proposed antenna is designed, simulated, and measured. A good agreement is shown between the experimental and simulated results.

Next-generation communication systems and wearable technologies aim to achieve high data rates, low energy consumption, and massive connections because of the extensive increase in the number of Internet-of-Things (IoT) and wearable devices. These devices will be employed for many services such as cellular, environment monitoring, telemedicine, biomedical, and smart traffic, etc. Therefore, it is challenging for the current communication devices to accommodate such a high number of services. This article summarizes the motivation and potential of the 6G communication system and discusses its key features. Afterward, the current state-of-the-art of 5G antenna technology, which includes existing 5G antennas and arrays and 5G wearable antennas, are summarized. The article also described the useful methods and techniques of exiting antenna design works that could mitigate the challenges and concerns of the emerging 5G and 6G applications. The key features and requirements of the wearable antennas for next-generation technology are also presented at the end of the paper.

This paper exhibits a low profile dual-polarized MIMO antenna with high isolation to meet the requirements of 5G smartphones. The integration between a vertically polarized slot and a horizontally polarized slot is investigated and applied for 28 GHz dual-polarized smartphone antenna. The antenna is combined with metasurface (MTS) to achieve high gain and more directivity. In order to design the metasurface, the characteristic mode analysis is used to investigate the performance of MTS at 28 GHz. The proposed antenna achieves high isolation coefficients better than 40 dB and cross polarization lower than-40 dB from simulated and measured results. The isolation between elements is achieved without any additional decoupling techniques. The proposed MTS slot antenna operates with 4 GHz bandwidth (26-30 GHz) with a realized gain of 11 dBi and efficiency of 90%. Four antennas (with eight ports) are positioned orthogonally at the corners of the mobile PCB to serve MIMO for 5G applications. The effect of MIMO antenna on the human is taken into consideration in power density term. Furthermore, the housing and components of smartphones are taken into our consideration in this paper. INDEX TERMS Dual polarized, MIMO, 5G, metasurface, characteristic mode analysis, and mobile handset antenna.