Design And Research Of Dual-band And High Isolation Base Station Antenna

In recent years,with the rapid development of 5G technology,the base station antenna plays a key role in information transmission in the communication system.The performance of the base station antenna will directly affect the entire communication system.The pursuit of high-speed,low-latency 5G communication brings greater challenges to the design of base station antennas.Base station antennas are generally large antenna arrays.In order to meet the requirements of antenna miniaturization and wide-angle scanning,the design of dual-band and high isolation base station antennas has become a research hotspot.This paper firstly introduces the realization and development of base station antenna,decoupling technology and dual-band base station antenna.Then,the theoretical knowledge related to the antenna is briefly explained.Further,two high isolation 5G base station antennas loaded with different decoupling structures and a dual-band 5G base station antenna are designed.The main research contents and conclusions are as follows:1.A±45°dual-polarized base station antenna element operating at 2.96GHz-4.32GHz is designed.The elements are formed into 1×4 and 4×6 antenna arrays,and a high isolation base station antenna array operating in 3.3GHz-3.8GHz is realized.By loading two decoupling structures,the separation wall based on split resonator ring and the array-antenna decoupling surface（ADS）,the isolation between the antenna elements of the 1×4 and 4×6antenna arrays can reach more than 20d B.The co-polarization isolation between the adjacent elements of 1×4 antenna array is improved by 6.6d B.2.On the basis of the first 1×4 antenna array proposed above,the element spacing is reduced to 0.43 λ₀（where λ₀ is the wavelength at the center frequency of 3.45GHz）,and a high isolation base station antenna that can scan at a large angle of±50°is realized.By loading the two decoupling structures of the slotted metal wall and the ADS with a square main reflector,the isolation between the elements of the 1×4 antenna array reaches more than20d B,the co-polarization isolation between the adjacent elements is improved by 7.4 d B,furthermore,the scanning performance is improved.By expanding the 1×4 antenna array to4×6 antenna array,and continuing to design an ADS structure loaded with sub-reflectors,the isolation between the elements of the 4×6 antenna array can meet the requirement of more than 20d B.When scanning at a wide angle of±50°,the gain drop is controlled within3d B.3.A dual-band 5G base station antenna covering 3.3GHz-3.8GHz and 4.8GHz-5.0GHz is designed.The high frequency resonance is obtained by loading a high frequency parasitic patch above the low frequency antenna,thereby realizing a dual-band base station antenna.However,the antenna with high frequency parasitic structure has a low gain in the high frequency band.By loading the metal shorting pins and the director structure,the gain of antenna in the high frequency band is greatly improved.Especially at 5.0GHz,the gain of antenna is increased by 5.41d B.The gain of antenna is over 7.6d Bi in the lower band and over 8.3d Bi in the upper band.The elements are formed into a 1×4 antenna array to verify array performance.The 1×4 antenna array not only meets the requirements of reflection coefficient and isolation in the required frequency band,but also has higher gain.The gain of 1×4 antenna array is 13.9d Bi-15.4d Bi in the low frequency band and 13.9d Bi-15.2d Bi in the high frequency band.