With the rapid growth of data flow in the fifth generation wireless communication system

millimeter wave technology has attracted broad attention in the fields of industrial and academic applications such as 5G.However

due to the high path loss

attenuation and multi-path interference

multi-input multi-output(MIMO)technology is introduced to improve the spectrum efficiency and coverage area of wireless communication.A compact notch millimeter-wave MIMO antenna with an overall size of 24mm×18mm×0.8mm is designed based on a loop-type decoupling structure.The antenna is etched on FR4-KB substrate entirely

and the notch of n258(24.25-27.5GHz)frequency band is realized by etching "H-shaped" slot on the antenna radiation patch.Furthermore

a loop-type structure is arranged on the ground plane to generate high frequency resonance points

which makes the MIMO antenna have a good decoupling effect.Simulation and test results show that the wideband millimeter-wave antenna operates in the frequency range of 20.9-33.2GHz (relative bandwidth up to 49%)

the isolation is greater than 18.2dB

which meets the isolation require ment of MIMO antenna the envelope correlation coefficient(ECC)is less than 0.004

and the antenna has good radiation efficiency and gain performance

which can be widely used in millimeter-wave MIMO antenna communication systems.