A novel design is introduced for dual-band operation at 28/38 GHz for improving microstrip antennas. Also, the design support circularly polarized antenna that works in millimetre band applications. This proposed antenna is attached to a circular hole in the centre of the patch with four slits embedded in the corners. Also, small holes are etched at sides of the patch to achieve the resonant frequencies and improve the return loss value with achieving very wide band at 38 GHz. A single-feed circularly polarized antenna at 28 GHz and 38 GHz with return loss − 30 dB and − 42 dB, respectively, which makes it suitable for operation at 5 G wireless communication designs. A single element design can cover the frequency ranges of 27.6–28.3 GHz at 28 GHz with bandwidth 2.5% and 35.2–47.2 GHz at 38 GHz with very wide bandwidth 32.4%. Simulated results show that the proposed antenna has good circular polarization in both frequencies of left-hand circular polarization (LHCP). On the other hand, MIMO antenna with four ports is constructed. The four ports are arranged at the corner and middle of substrate with dimension 100 × 75 × 0.508 mm³. Meanwhile, resonant implementation frequencies in a millimetre wave of the MIMO achieved more mutual coupling minimization that effectively accomplished <− 36 dB. In addition, the numerical and experimental results are achieved to evaluate the performance of both single- and four-port MIMO antennas. The diversity gain (DG), envelop correlation coefficient (ECC), total active radiation coefficient (TARC) and channel capacity loss (CCL) also are calculated, and the results are suitable for 5 G applications.

引入了一种新颖的设计，用于在28/38 GHz的双频操作，以改善微带天线。此外，该设计还支持在毫米波段应用中工作的圆极化天线。拟议中的天线连接到贴片中心的圆形孔，在角上嵌入四个缝隙。同样，在贴片的侧面刻蚀小孔，以实现谐振频率并通过在38 GHz处实现非常宽的带宽来改善回波损耗值。28 GHz和38 GHz的单馈圆形极化天线分别具有− 30 dB和− 42 dB的回波损耗，这使其适用于5 G无线通信设计。单个元件设计可以覆盖带宽为2.5％的28 GHz频率范围内的27.6–28.3 GHz和带宽为32.4％的38 GHz频率范围内的35.2–47.2 GHz。仿真结果表明，所提出的天线在左旋圆极化（LHCP）的两个频率上均具有良好的圆极化。另一方面，构造了具有四个端口的MIMO天线。四个端口布置在基板的角和中间，尺寸为100×75×0.508 毫米³。同时，MIMO毫米波中的谐振实现频率实现了更多的互耦最小化，有效实现了< − 36 dB。此外，获得了数值和实验结果，以评估单端口和四端口MIMO天线的性能。还计算了分集增益（DG），包络相关系数（ECC），总有效辐射系数（TARC）和信道容量损耗（CCL），这些结果适用于5 G应用。