Research And Design Of High-isolated Dualband MIMO Antennas

The antenna,as the terminal of the mobile communication system,has the function of transmitting and receiving data,and is an important part of the modern mobile communication system.With the development of next-generation mobile communication technology,MIMO technology has become a research hot topic.MIMO antennas have also become an indispensable part of new-generation mobile communication systems.Without increasing bandwidth and power,MIMO antennas use multiple antennas.The unit increases the channel capacity of the communication system and improves the transmission efficiency.However,in order to meet the requirements of miniaturization of wireless communication,the array of multiple antennas will inevitably produce mutual coupling between antennas and affect the relevant indicators of the antennas.Therefore,MIMO antennas have higher requirements for the isolation between antennas,which has become a difficulty and focus in MIMO antenna technology.This article also focuses on how to improve the isolation of dual-frequency MIMO antennas as follows:1.A dual-band MIMO antenna is designed using the decoupling network and the ground slot.The antenna uses meandering technology and the method of adding short-circuit branches to increase the electrical length and reduce the size of the basic antenna unit.The antenna is analyzed quantitatively for the inverted T decoupling network by even and odd mode analysis method.The theoretical values of network parameters is analyzed,which is verified through simulation to make the low-frequency isolation higher than 20 dB.The ground “mountain”-shaped depression structure extends the ground current path in the high frequency range and reduces the high frequency range.In the end,the antenna meets the requirements of high isolation at low and high frequencies,and has good radiation characteristics,which is suitable for miniaturized communication systems.At the same time,the design method is universal and applicable to any basic antenna unit,and global optimization and shorten design cycle is avoided.2.A dual-band MIMO antenna is designed using the resonant network.The resonant network simultaneously satisfies the dual-frequency decoupling of the antenna.A dual-band MIMO antenna decoupling network model is established.By analyzing its admittance parameters,adding phase-modulation network and isolation network to make it meet the isolation characteristics,and adding a dual-band matching network to meet the dual-band matching characteristics,the isolation of the antenna in the two frequency bands of 2.35 GHz ~ 2.55 GHz and 5.5GHz ~ 6GHz is greater than 20 dB,and the reflection coefficient is less than-15 dB.This design method is also universal.3.A single-radiation dual-band MIMO antenna is researched and designed.Starting from the most basic decoupling ideas,a circuit model with isolation characteristics is designed,and it is tuned by ADS to meet its requirements in two frequency bands.The requirement of high isolation,and then the circuit is evolved into an antenna model to make it have radiation characteristics and impedance matching.The antenna is designed from the perspective of the opposite of the previous two antennas,and first meets the isolation requirements.Designed to match,and designed antenna meets MIMO antenna requirements...