Method For Evaluating The Shape And Performance Of High-band Antennas

In response to the increasing number of users needing access to large amounts of wireless data anytime and anywhere,the fifth generation(5G)communication system significantly increases its requirements of wireless capacity,communication quality and sensitivity,and the application of phased array technology in the field of 5G communication has ushered in a new opportunity.The 5G phased array base station antenna with microstrip patch antenna as the element conforms to the commercial evolution direction of 5G communication system,which is active,integrated and miniaturized.However,this will increase the integration degree of the RF device and antenna element in the base station antenna system,and also increase transmit power of the base station to balance pass loss,so that the antenna working thermal environment will face more severe challenges.In addition,since 5G millimeter-wave beam has high-gain,high-sensitivity and it is in the beam scanning or beam tracking state at the moment,the influence of the element random position error generated during array processing and element assembly on communication performance is also becoming more and more prominent.In the paper,5G base station phased array antenna is taken as the research object,the electromechanical coupling model with structure parameters and communication indexes is established,the sensitivity calculation model is derived,and Research is carried out from two aspects:the influence mechanism of structural error and the tolerance design based on sensitivity.The specific work content is as follows:(1)The electromechanical coupling model between the 5G phased array base station antenna and the important communication index-channel capacity,is derived and verified.Based on the Shannon formula and electromagnetic wave transmission theory in communication theory,the coupling relationship model between channel capacity and electrical properties of transmitting and receiving antennas in the communication system is derived.The coupling relationship between the attitude deflection of the rectangular microstrip patch antenna unit and its own pattern is clarified.Therefore,an electromechanical thermal coupling model of microstrip patch array antenna considering element offset,pointing deflection and temperature feeding error is established and verified with HFSS simulation results under ideal and deformation conditions.The simultaneous two-coupling model is used for downlink communication.The simultaneous coupling model is used to obtain the direct influence coupling model of the 5G phased array base station antenna array structure error and the feeding error on the channel capacity in the downlink communication link.(2)Based on electromechanical thermal coupling models established by the 5G phased array base station antenna for each communication index,the influence mechanism of the structural error of the base station antenna in the scanning and non-scanning states on the antenna pattern and channel capacity is studied.Microstrip patch unit operating at 28 GHz is designed and optimized in HFSS software and 16?16 large scale array is built.Taking the 8?8 sub-array corresponding to one of the beams as the research object,coupling models are firstly used to analyze the changes of the antenna pattern,channel capacity and signal-to-noise ratio under the thermal load generated by the RF device heating.Then,the influence degree of the element random position error of x,y,z directions with different standard deviations in non-scanning state on each communication index is compared.The results show that the installation flatness mainly affects gain,pointing and channel capacity,and the installation accuracy mainly affects the far sidelobe.Therefore,the influence of different installation flatness on each communication index in the beam scanning state is further compared,and the performance of each index decreases as the scanning angle?or standard deviation?_z increases.(3)Based on the electromechanical coupling model of electric field intensity and channel capacity,the sensitivity model of each communication index to the element position error is studied and the structural tolerance is designed accordingly.In order to reduce the cost of base station deployment and ensure communication quality,quantitative analysis of each element tolerance is performed in view of different influence degrees of each elements.Firstly,the sensitivity calculation models of the electric field strength and channel capacity to the element random position error are derived respectively,and the x,y,z sensitivity distribution maps of each working angle are compared.Then a specific method for determining the element tolerance is proposed,and the installation accuracy and flatness of each element in the 5G phased array base station antenna model are obtained according to the specific requirements of each communication index.The final simulation results(gain loss 0.2029dB,channel capacity variation 2.2164Mbps and maximum sidelobe level elevation 2.6253dB)demonstrate the feasibility and effectiveness of the proposed method.