This paper presents a dual-band 28/38 GHz two elements multiple-input multiple-output (MIMO) antenna with high isolation for 5G applications. The suggested antenna is a monopole with rectangular and triangle stubs added to the patch and a partial ground plane to achieve the dual band’s behavior. Two elements of the suggested antenna are combined and placed orthogonally to achieve the high isolation features of the MIMO configuration at 28/38 GHz. The MIMO configuration has a size of 27.65 $$\times$$ × 12 $$\times$$ × 0.273 mm3. The suggested MIMO prototype is fabricated and tested. The tested results achieved dual frequency bands with S11 lower than − 10 dB within two frequency bands (26–30 GHz and 36–41.5 GHz) and S21 lower than − 20 dB through the two operated bands. The suggested antenna has semi-omnidirectional radiation patterns in both planes. As well, its measured peak gain is 5.2 dBi and 5.3 dBi at the two operated frequency bands, respectively. Also, the MIMO parameters are extracted to validate the simulated results. The simulated and tested results have a good matching within the two operating bands which suggests the proposed structure be utilized in 5G communications.

A dual band monopole antenna with triangle stubs operated at 28/38 GHz applications is introduced. The introduced dual band antenna is used for next 5G applications. The introduced antenna is designed on a Rogers RT 4003 with height h = 0.203 mm, dielectric constant ɛr = 3.55 and over dimensions of 12×12×0.237 mm3. The simulated results show that the presented design has two bands, the first one is from 25.9 to 30.4 GHz and the second is from 36.4 to 40.2 GHz with peak gain of 4.54 dB, 4.21 dB in the first and second frequencies respectively. The simulated radiation efficiency for the first and second frequencies is 94% and 96.6%, respectively. There are some small discrepancies between simulated and measured findings due to the fabrication and measurement equipment.

In this paper, a 38 GHz 4-port multiple-input multiple-output (MIMO) antenna with considerable isolation and gain enhancement for 5G applications is introduced. The suggested antenna element is a monopole antenna composed of a circular patch with a rectangular slot etched from it and a partial ground plane is used to extend the desired frequency to operate from 36.6 GHz to 39.5 GHz with a center frequency of 38 GHz. The high isolation is achieved by arranging the four elements orthogonally and adding four stubs to reduce mutual coupling between elements at the desired frequency bands. The gain improvement is also introduced by placing a frequency selective structure (FSS) which is designed at the same frequency bands of the antenna under the suggested MIMO antenna to act as a reflector. The proposed four-element MIMO with the FSS prototype is built and tested in order to confirm the simulated results. The suggested antenna operated from 37.2 GHz to 39.2 GHz with an isolation of less than 25 dB across the obtained frequency range. The peak gain of the antenna is enhanced from 5.5 dBi to around 10 dBi by utilizing the FSS structure; furthermore, the back radiation is enhanced. The MIMO performance is validated by extracting its parameters and comparing with the simulated results. The results extracted from the simulation and the measurement show satisfactory matching along with the target band, indicating that the proposed structure could be used for 5G communications.