Design Of New Left-Handed Materials And Its Application In 5G MIMO Antennas

Left-handed materials belong to artificial metamaterials and do not exist in nature.Compared with ordinary materials,left-handed materials have many distinctive electromagnetic properties,which have attracted many scientists' attention and research.More and more new left-handed materials have been designed.At present,the left-handed unit structures are mostly bilaterally symmetric.Its advantages lie in its simple structure and wide application range,but it also limits the design space of the unit structure.Therefore,the study of asymmetric left-handed structures is increasing.In addition,the research of left-handed materials in 5G MIMO antenna is less at present,more focused on ultra-wideband,WLAN and WIMAX bands.Therefore,the left-handed materials have great application prospects in 5G MIMO antennasThe main contents of this paper are as follows1.First,a spoon-shaped left-handed unit strcture with bilaterally cyclic coupling is proposed,and then it has been improved.Another magnetic resonance circuit is loaded inside,which enhances the magnetic resonance intensity,reduces the size and improves the space utilization ratio.Then another improvement is made to the original spoon-shaped unit structure,forming a hook-shaped left-handed unit structure,which further strengthens its magnetic resonance effect and improves its space utilization.Finally,the dual left-handed frequency band is realized by adding two more hook-shaped structures to the outside of the hook-shaped unit structure to form a dual bilaterally cyclic coupling hook-shaped left-handed material.2.A combined type left-handed structure is proposed.Firstly,two kinds of left-handed unit structures with complementary dual single-negative bands are designed as units "0"and"1".Unit"0" has equivalent negative permeability and equivalent negative permittivity near 2.6 GHz and 3.5 GHz respectively,while unit "1" has equivalent negative permittivity and negative permeability near 2.6 GHz and 3.5 GHz respectively.Then the two units are combined to form a combined type left-handed structure.The double negative left-handed characteristics are realized near both 2.6 GHz and 3.5 GHz.3.Firstly,a microstrip patch antenna with rectangular slots is designed.Its working frequency band covers 2.6,3.5 and 4.85 GHz of low and middle frequency bands in 5G communication system.Then the rectangular slots are replaced by spiral slots to improve the antenna performance.After that,a two-element MIMO antenna is formed by the improved microstrip patch antenna with spiral slots,which has the advantages of small size and high isolation.Finallyl,the gain of the MIMO antenna is also improved by loading the previously designed combined type left-handed material.4.Firstly,a double-G-shaped microstrip monopole antenna is designed.Its working frequency band also covers the low and middle frequency bands in 5G communication system,and its bandwidth is much wider than that of the previously microstrip patch antenna.After that,the bandwidth of the antenna at low frequency is greatly broadened by asymmetrically loading the dual bilaterally cyclic coupling left-handed slots designed previously on the ground plane.At last,an asymmetric two-element MIMO antenna is formed by the double-G-shaped microstrip monopole antenna,and the isolation between the two elements of the MIMO antenna is improved by loading the previously designed bilaterally cyclic coupling hook-shaped left-handed structure.