A Study Of Low Profile And High Isolation Dual-polarization Microstrip Linear Antenna Array At S-band

With the rapid development of wireless communications,spectrum resources are increasingly scare.How to make full use of limited spectrum resources to improve the data rate and quality of wireless communications is critical.The dual-polarized antenna is composed of two orthogonal linear polarized radiators that feature the smallest spatial correlations,which can effectively save the number of single directional base station antennas and improve the spectrum utilization.Simultaneously,the antenna can not only deal with the polarization mismatch between transmitter and receiver,but also release of multipath fading.The polarization mode of the dual-polarized antenna is a kind of polarization diversity,which can also reduce the overall cost of the antenna system.Actually,the base station antenna plays a key role in the mobile communication system,and its performance will directly affect the coverage quality of the whole communication network.Currently,the integrated base station antenna has been attracted extensive attentions,among which low profile is one of the keys point to antenna miniaturization,and how to enhance the isolation among the antenna element is of great significance for such a kind of antenna.The thesis discusses the low profile and high isolation dual-polarized antenna and array.Content of the thesis includes:Firstly,this thesis introduces the research background and development status of base station antenna and dual-polarized antenna in recent years,and briefly describes the radiation principle and basic specifications of antenna.Moreover,taking a two-element array as an example,the principle of pattern multiplication and the array factor of a one-dimensional linear array are derived.Secondly,a low profile and high isolation dual-polarized antenna is designed,where the horizontal polarization is fed by H-type slot coupling,while the vertical polarization is realized by reverse phase feed based on slotline based wideband balun.The differential feed is adopted for the element to improve the polarization isolation,and the theoretical analysis and simulation design are given.The results are as follows:the working frequency bands of VSWR<1.5 are 2.43-2.50 GHz and 2.40-2.53 GHz in the direction of horizontal and vertical polarization,and the isolation exceeds 62.7 dB,which meets the design requirements of the antenna unit.Finally,based on the developed element,a 1×8 dual-polarized linear array is designed and full-wave simulated,where the element spacing is 0.5?₀??₀ is the wavelength at 2.45 GHz in free space?.Further,the mutual coupling and the decoupling technique are discussed in detail.In this dissertation,T-type neutralization line is adopted for decoupling purposes.The in-phase decoupling effect of adjacent cells reaches 20 dB,and the isolation within the array is better than 40.3 dB.