The antenna dimension was 40 mm \(\times\) 40 mm (0.42\(\lambda_{0}\)\(\times\) 0.42\(\lambda_{0}\)) (\(\lambda_{0}\) was the wavelength at the first lower frequency). A square-shaped defected ground framework was placed on the ground to improve the isolation. Etching square-shaped slots on the ground plane achieved the return losses S11 \(<\) -10 dB and a 26 dB isolation in the entire operating band of 3.2-12.44 GHz (UWB (3.1-10.6 GHz) and the X-band (8-12 GHz) spectrum and achieved good isolation bandwidth of 118.15%. The MIMO performance was evaluated in terms of diversity gain (DG), envelope correlation coefficient (ECC), Channel Capacity Loss (CCL), and mean effective gain (MEG). [PERSON] et al. presented a 12-port MIMO antenna system for 5G/WLAN applications (contribution 3). The proposed antenna system consisted of two types of antenna modules: an L-shaped antenna module covering the C-band (3.4-3.6 GHz) for 5G mobile applications and a folded monopole module for the 5G/WLAN mobile application band (4.5-5.9 GHz). Each two antennas formed a pair, six pairs in total, forming a 12 \(\times\) 12 MIMO antenna array, and the elements between the antenna pairs could achieve an isolation of 11 dB or more without additional decoupling structures. The experimental results showed that the antenna could cover the 3.3-3.6 GHz and 4.5-5.9 GHz bands with an overall efficiency greater than 75% and an envelope correlation coefficient of less than 0.04. Finally, the one-hand holding mode and two-hand holding mode were discussed to demonstrate their stability in practical applications, and the results showed that they still exhibited good radiation and MIMO performances when operating in both modes. Another design of multiband MIMO antennas along with high-isolation characteristics using FR-4 material has been proposed (contribution 4). It operates at the 3.50 GHz, 5.50 GHz, and 6.50 GHz frequencies for 5G cellular, 5G WiFi, and WiFi-6, respectively. The two-element MIMO multiband antenna was miniaturized to 16 \(\times\) 28 \(\times\) 1.6 mm\({}^{3}\), making it desirable for devices operating in 5G bands. High isolation (>15 dB) was attained with thorough testing without employing a decoupling scheme in the design. Laboratory measurements resulted in a peak gain of 3.49 dBi and an efficiency of around 80% in the entire operating band. The evaluation of the presented MIMO multiband antenna was carried out in terms of ECC, DG, total active reflection coefficient (TARC), and CCL. The measured ECC was less than 0.04, and the DG was well above 9.50. The observed TARC was also lower than \(-\)10 dB, and the CCL was below 0.4 bits/s/Hz in the entire operating band. [PERSON] et al. presented a novel design of a reconfigurable MIMO antenna array of a 3D geometry-based solar cell integration that operated at sub-6 GHz for self-powered applications in a 5G modern wireless communication network (contribution 5). The proposed antenna array provided three main frequency bands around 3.6 GHz, 3.9 GHz, and 4.9 GHz, with excellent matching impedance of S11 \(\leq\)\(-\)10 dB. The proposed MIMO array was constructed from four antenna elements arranged on a cubical structure to provide a low mutual coupling, below \(-\)20 dB, over all frequency bands of interest. Each antenna element was excited with a coplanar waveguide (CPW). The proposed radiation patterns were controlled with two optical switches of Light-Dependent Resistors (LDRs). The proposed antenna array was fabricated and tested experimentally in terms of S-parameters, gain, and radiation patterns. The maximum gains were found to be 3.6 dBi, 6.9 dBi, and 3.5 dBi at 3.6 GHz, 3.9 GHz, and 4.9 GHz, respectively. It was realized that the proposed array realized significant beam forming by splitting the antenna beam and changing the main lobe direction at 3.9 GHz after changing LDR switching statuses. Such an antenna array was found to be very applicable for femtocell wireless communication networks in 5G systems.