Research And Design Of Multibeam MIMO Antenna

For a long time,the channel capacity of the wireless communication system is limited by the lacking spectrum resources.This is the main obstacle to the pursuit of high capacity and high date transmission rate in communication.It is also a difficult problem for traditional communication technology.Fortunately,multiple input multiple output(MIMO)technology has been proposed.In the complex multi-path transmission environment,MIMO technology improves the channel capacity and communication quality of wireless communication without occupying other frequency band resources and more emission power.It is one of the key technologies of the fourth generation mobile communication system(4G)and the fifth generation mobile communication system(5G),which is widely concerned and studied.In the thesis,two kinds of MIMO antennas are designed.The main contents are as follows:1?Multi-beam MIMO antenna based on spoof surface plasmon polariton.First of all,an end-fire antenna based on spoof surface plasmon polariton is designed,which consists of monopole as the feed,reflector and split ring resonators.Many split ring resonators are arranged periodically on both sides of the substrate.Simulated and measured results show that the antenna covers the frequency band from 9.1GHz to 11GHz,the normalized radiation patterns of E plane and H plane has good beam directivity.This antenna has good end-fire performance.Finally,the MIMO antenna is made up of six identical end-fired antennas which are arranged by rotating at 60°.The experimental results show that the reflection loss of every unit of MIMO antenna is less than-10 dB in the frequency band of 9-10.8GHz,and the isolation is greater than 30 dB.The MIMO antenna forms six beams in six directions.2.Multi-band and multi-beam MIMO antenna for wireless access point.Firstly,the traditional planar dipole is with the multi-band and impedance matching which are realized by adding the branches and grooves,and is regarded as an array element.It covers three frequency bands of 2.4-2.48GHz,3.4-3.6GHz and 5.15-5.85GHz.A four-port MIMO antenna is made up of four same array elements which are arranged by rotating at 90°.In order to reduce the back radiation and increase the forward gain,a 100mm×100mm×1mm of pure aluminum plate as a reflector is positioned at the bottom of the antenna with 12mm.The simulated results show that the antenna covers proposed three frequency bands and has a great isolation,and it is treated as a MIMO unit.Finally,a sixteenth-port MIMO antenna is formed by four same MIMO units which are arranged by rotating at 90°.