| In order to cope with the explosive mobile data traffic growth in the future,massive device connections,and various emerging new services and application scenarios,the fifth generation mobile communication(5G)system came into being.To meet the exponential growth of user and service capacity in mobile broadband communications,and realize the 5G vision.The first problem to be solved is the capacity of wireless communication.Millimeter wave large-scale antenna array technology and high and low frequency hybrid networking are important choices to achieve 5G high rate and large capacity communication.At present,the 3.5GHz 5G base station network is nearing completion,and millimeter wave 5G base stations are just getting started.Microwave millimeter wave cross-band base station antennas are an inevitable trend,and microwave millimeter wave cross-band phased array antennas are the key technologies.The research of microwave and millimeter wave cross-band dual-frequency dual-polarized microstrip antennas can provide important reference value for the research of microwave millimeter wave cross-band phased array antennas,and promote the development of 5G.The microstrip antenna has the characteristics of small size,low profile,easy manufacturing and easy conformal,which can meet the requirements of wireless communication technology for miniaturization and integration of the antenna.In this paper,three cross-band dual-frequency dual-polarized microstrip antennas are designed.The first multi-layer cross-band dual-frequency dual-polarized microstrip antenna adopts a stacked structure.The antenna radiation patch is composed of a lower patch(small square patch)and an upper patch(ring square patch).The ring square patch is printed on the uppermost substrate with square through holes,and the small square patch is printed on the second substrate.The coaxial probe directly feeds the small square patch.The small microstrip line above the lowermost substrate is connected to the coaxial probe,and the other segment is connected to another copper probe to feed the ring square patch.The antenna simulation results show that the antenna 10 d B impedance band is4.8GHz-5GHz,24.7GHz-30 GHz.The main polarization in the high-frequency radiation pattern of the antenna is greater than the cross polarization by more than 20 d B.The second type of antenna uses a single-layer patch structure,which is designed to work on the same plane at 4.9GHz and 26 GHz radiation patches.The high-frequency and low-frequency radiation patches share a feed port and can be fed in two vertical directions to achieve linear polarization radiation in the cross direction.Simulation results show that the antenna works at 4.9GHz and 26 GHz,and the 10 d B impedance band is 4.85GHz-4.95 GHz and 25.67GHz-26.23 GHz.Finally,the actual product is made.But the measured high-frequency radiation pattern of this antenna has the problems of distortion and poor cross-polarization isolation.The reason is when feeding the high-frequency radiation patch,the feed signal will be coupled to the vertical direction of the high-frequency radiation patch through the microstrip line connected to the low-frequency radiation patch.A low-pass filter can be used to cut off the channel between the high-frequency radiation patch and the low-frequency radiation patch.The third type of single-layer cross-band dual-frequency dual-polarization filter antenna uses single-port feeding and contains two high-frequency and low-frequency radiation patches on a plane.Both high-frequency and low-frequency radiation patches can be fed in two vertical directions to achieve linearly polarized radiation in the cross direction.And the antenna by inserting a low-pass filter between the feed point and the low-frequency radiation patch to significantly improve the cross-polarization isolation in the high-frequency radiation pattern.The research results show that the 10 d B impedance band of the antenna is 4.77GHz-4.85 GHz and 25.45GHz-26.3GHz.The radiation patterns of the two radiation frequencies show good linear polarization characteristics,and the main polarization is 20 d Bi larger than the cross polarization.The three antennas designed in this paper,the first type of antenna adopts a layered structure realizing a cross-band dual-frequency dual-polarization radiation.The second antenna adopts a single-layer patch structure,single-port feeding,and realizes cross-band dual-frequency dual-polarized radiation on the same plane.The third type of antenna adopts a single-layer patch structure,innovatively uses a low-pass filter to cut off the microstrip line coupling channel of the high and low frequency radiation patch,improves the isolation of high frequency radiation,and realizes dual-frequency dual-polarization across frequency radiation.The three antennas designed in this paper will be used in future 5G communication terminal antennas shared by microwaves and millimeter waves,or MIMO antenna array elements of 5G communication base stations.value. |
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