Research And Implementation Of 5G FR2 Band Wideband Circular Polarization Microstrip Antenna

Compared with 4G,the 5G new air interface can support higher frequencies,which can be divided into two frequency bands(FR1,FR2).The FR1 frequency band is a frequency band currently being used for 5G commercial use in China,and the frequency band is located below 6 GHz.FR2 is the 24.25GHz-52.6GHz band,which is the main frequency band to be adopted in the next stage of China's 5G communication development.Designing a millimeter wave antenna that can be used in the 5G FR2 frequency band has become one of the important directions of antenna research in recent years.In addition,in view of the multipath interference problem that occurs during millimeter wave propagation,the circularly polarized antenna has a good suppression effect.Based on the above research background and the current problems of narrow bandwidth,complex structure,and high profile in some millimeter wave antenna research,this thesis designs three millimeter wave circularly polarized antennas that can be used in the 5G FR2 frequency band.The main content of this thesis is as follows:1.A circularly polarized millimeter wave antenna with L-shaped branches has been designed.The antenna structure is based on the microstrip wide slot antenna structure,which can effectively expand the antenna bandwidth.The antenna radiates circularly polarized waves by adding a pair of L-shaped perturbation branches at the diagonal of the square slot.The results show that the resonant frequency of the antenna is 24.4 GHz,the impedance bandwidth is 25.8%,the axial ratio bandwidth is 47.1%,and the maximum gain is 4.32 dBi.The antenna radiates double circularly polarized waves along the Z axis.The antenna structure size is 5.5×5.5×0.127 mm~3,which has the advantages of miniaturization and simple structure.2.A circularly polarized millimeter wave antenna with a parasitic ring has been designed.The antenna feed structure is microstrip feeder side feed,easy to adjust the antenna input impedance.The antenna is designed with single layer structure,which has the advantages of simple structure,low profile and easy machining.By adding parasitic rings,the antenna bandwidth is improved effectively.The results show that the resonant frequency of the antenna is 37.5 GHz,the impedance bandwidth is 3.94%,the axial ratio bandwidth is 4.01%,the maximum gain is 6.56 dBi,and the antenna radiates the dextral circularly polarized wave.3.A four-element millimeter wave circularly polarized MIMO antenna has been designed.The MIMO antenna is composed of four circularly polarized antenna elements with the same structure,which are rotated clockwise by 90°in turn.By changing the distance and arrangement Angle between antenna elements,the isolation degree between antenna elements is improved effectively.The results show that the resonant frequency of the antenna is 25 GHz,the impedance bandwidth is 9.78%,the axial ratio bandwidth is34.79%,the maximum gain is 4.73 dBi,and the antenna radiates double circularly polarized waves.The ECC index of the antenna is less than 0.01,the isolation degree is more than 20dB,and the independence of the antenna elements is strong.