Design And Performance Compensation Of High Gain And Wideband Array Antenna

With the rapid development of mobile communication,satellite navigation,electronic countermeasures and other fields,the electromechanical coupling effect of array antennas is becoming more and more significant when it becomes high density and integration.On the one hand,higher requirements are put forward for the performance indicators of array antennas,and the demand for high gain,wide band and low profile antennas is becoming more and more prominent,which increases the difficulty of antenna design.On the other hand,with the improvement of the working frequency band and the harsher service environment of the array antenna,the electrical performance of the antenna is more sensitive to the influence of the deformation of the array structure under the disturbance of the environmental load,which increases the difficulty of guaranteeing the electrical performance.However,in the traditional antenna design,it is difficult to balance the design parameters among profile height,bandwidth and gain,and it is difficult to achieve high gain,wide frequency band,and low profile at the same time.At the same time,in the process of antenna service,for the electrical performance distortion when the array is greatly deformed,only relying on phase correction,excitation amplitude and phase adjustment and other methods have limited effect on electrical performance compensation.Therefore,this thesis designs a high-performance array antenna,and proposes an electromechanical synergistic compensation method for antenna performance based on SMA for the loss of electrical performance under structural deformation.Firstly,an array antenna based on microstrip dipole antenna is proposed.The fan-shaped feed structure and the elliptical radiation patch generate multiple resonant paths,which broaden the antenna bandwidth,and the gain of the antenna is improved by the guiding effect of the parasitic patch.The simulation analysis and experimental results show that the impedance bandwidth of the antenna is 22% at 8.97GHz～11.20 GHz,and the peak gain of the antenna reaches 7.6 d B.Through the array of antenna units,the simulation results show that the 4×8 array antenna achieves stable radiation characteristics within impedance bandwidth,and its gain is 21.64 d B.Secondly,this thesis analyzes the SMA constitutive model and mechanical properties,establishes the relationship between the driving force and the displacement of the SMA spring,and proposes a deformation compensation method for the front structure based on SMA.The simulation analysis shows that when the maximum deformation of the array structure is one-half wavelength,the root mean square error of the array surface can be reduced from 4.8536 mm to 1.7207 mm by this deformation compensation method,and the surface accuracy is improved by 64.5%.The feasibility of the SMA-based front structure deformation compensation method is verified.Finally,to effectively compensate the electrical performance of the array when large deformation occurs,this thesis optimizes the layout of the SMA spring to effectively improve the accuracy of the array surface,determines the amplitude and phase adjustment of the array element excitation current based on the principle of least square error,and an electromechanical synergistic compensation method for antenna performance based on SMA is proposed.Taking a 4×8 array antenna as an example for simulation analysis,when the maximum deformation of the array is one-half wavelength,the gain loss is 6.742 d B.The gain loss is reduced to 1.146 d B by the traditional electrical compensation method,and the gain loss is reduced to 0.237 d B by the synergistic compensation method,the compensation effect is improved by 13.48%,which verifies the effectiveness of the electromechanical synergistic compensation method.