| As a device that transmits and receives electromagnetic waves in a radio system,the antenna plays an important role in transmitting information,and its performance directly affects the reliability of the entire system.As one of the antenna forms,although the development time of microstrip antenna is relatively short,it has become an important branch of the antenna field.The development of microwave integration technology and the advancement of new manufacturing technologies have promoted the development of microstrip antenna from theory to practice.Since their inception,with the characteristics of low profile,easy conformal,low cost,and mass production,the microstrip antenna has been widely used in satellite communications,navigation,remote sensing and telemetry,medical devices and other engineering systems.However,its electrical performance will be affected because the service load,resulting in electrical performance degradation.For example,in an airborne microstrip antenna,the antenna structure will change due to the vibration of the fuselage,which will not only cause the microstrip antenna element position shift,but also the antenna element will also deflect.The deflection of antenna element can lead to the change of array element pattern,which will affect the airborne radar detection performance.After the electrical performance of the antenna deteriorates,certain methods must be used to compensate the electrical performance to ensure its reliable service.This paper takes the microstrip array antenna as the research object,and studies the electromechanical coupling problem and the electrical performance compensation problem after the antenna element topography changes.The research contents of this paper are as follows:(1)The electromechanical coupling model of microstrip array antenna considering the morphological changes of antenna elements is established.Firstly,the basic radiation theory of microstrip antenna is introduced.By studying the influence of antenna element position offset and deflection on electric performance,the electromechanical coupling model of microstrip antenna under the change of antenna elements' morphology is established based on the ideal antenna pattern function.In HFSS software,taking the microstrip array antenna with 1.5GHz central operating frequency and 2x8 arrangement as an example,the correctness of the coupling model is verified under 4 conditions where the bending radius are ?/ 8,?/ 5,?/ 3 respectively,and in the undeformed condition.The maximum error between the calculation results of the coupling model and the simulation results of HFSS is 2.78%,which meets the engineering requirements,thus verifying the correctness of the established coupling model.This theory lays a theoretical foundation for the analysis and compensation of the electrical performance of the microstrip array antenna.(2)The change rule of electrical performance after morphology change of microstrip antenna elements is studied.The complex working environment makes the antenna element deviate and deflect from its position.Also random errors will occur during manufacture and installation.The existing research does not consider the deflection of antenna element when analyzing the influence of structural deformation and random errors.Therefore,the influence of structural deformation,random error and antenna element deflection on antenna electrical performance is analyzed.Firstly,without considering random error,a coupling model between gain loss and bending deformation is established for rectangular microstrip array antenna.Then,under the combined influence of array deformation,random error and antenna element deflection,the variation rule of the antenna electrical performance of fixed and changed array dimensions under bending deformation is discussed respectively.(3)Based on the electro-mechanical coupling model of microstrip array antenna considering the changes of array elements' morphology,phase compensation and amplitude-phase compensation based on least squares method for element position offset and deflection are proposed.The phase compensation realizes the compensation effect by calculating the phase compensation of the excitation current caused by the change in the topography of the antenna element.The amplitude-phase compensation based on the least square method compensates the electrical performance by calculating the compensation amount of the excitation current amplitude and phase at the same time.Then the microstrip array antenna arrange in rectangular shape is compensated under 9 bending deformation conditions by phase compensation and amplitude-phase compensation based on least square method,and the compensation effect is analyzed.Finally,phase compensation is compared with amplitude-phase compensation based on least squares in terms of computational complexity and compensation capability.The results show that the two methods have a good compensation effect on the main lobe area.Compared with the amplitude-phase method based on the least square method,the phase compensation has a smaller amount of calculation,but the amplitude-phase compensation is more effective than the phase compensation in the whole side lobe area.(4)A Software for calculating and compensating the electrical performance of microstrip array antenna considerring morphology change has been developed.According to the established electromechanical coupling model of microstrip array antenna based on the morphology change of antenna element and two methods of phase compensation and amplitude-phase compensation,the software for calculating and compensating the electrical performance of microstrip array antenna under the morphology change of the element is developed by using C++ Builder.With the help of this software,it is possible to predict the changes in electrical performance in the service environment.Measures can be taken before the antenna performance cannot meet the needs,and the electrical performance compensation amount can be calculated.The software can quickly calculate the electric performance of the deformed antenna structure and compensate the electric performance by using the two compensation methods proposed.Finally,an example is used to complete the analysis and compensation of the electrical performance of the microstrip array antenna with unit morphology changes,which verifies the validity and practicability of the software.With the help of this software,it is possible to quickly predict the electrical performance changes of the antenna under the service environment based on the multidisciplinary theory,and compensate the electrical performance of the deformed antenna to ensure the reliable and stable service performance of the antenna. |
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