Research On Optimization Method Of Ground-penetrating Radar Array Antenna For Hydraulic Engineering

As an important hydraulic engineering,dams play a decisive role in the country's economic development and the safety of production.Due to the historical problems,Because of the poor construction quality and prolonged periods of use,there is a problem of seepage and water leakage in the dam.It not only causes the waste of water resources,but also poses a great threat to the people's life and property and the safety of the country's production.In order to avoid the occurrence of these things,it is necessary to do a good routine test.Ground penetrating radar(GPR)is a convenient nondestructive testing method.Compared with other methods,GPR has some advantages,such as convenient operation,no damage to the detection area,and obvious detection effect.In order to get better results,the ground penetrating radar is required to have a reasonable antenna design.This paper mainly focuses on the optimization method of GPR antenna array antenna.Firstly,the characteristics of the electromagnetic wave propagation of GPR are introduced.Combined with the Maxwell equation,constitutive relations,and the electrical and magnetic properties of the propagation medium,the loss of electromagnetic wave in the process of propagation and the law of reflection and refraction are analyzed.In the initialization of the Antlion algorithm,the Weibull distribution is selected by comparing different probability density distribution functions,which improves the convergence speed of the algorithm.Secondly,analyze the mechanism of ground penetrating radar,introduce the influence of different parameters on the ground penetrating radar resolution and depth,such as center frequency,time window,sampling rate,distance measurement etc.On this basis,according to the principle of Yee grid discretization,a two-dimensional dam foundation seepage model is established by MATLAB,and the model is simulated.The simulation results show that for the target with depth of 5~6 meters,the detection results are excellent in imaging effect and resolution when the center frequency is 100 MHz.Then,Introduces the basic Antlion optimization(ALO)algorithm and put forward the improved chaos antlion optimization(CALO)algorithm.Since chaotic search helps to improve the speed of trap pit contraction by adaptive parameters,based on Weibull distribution,the chaos adaptive factor is introduced,and CALO is proposed.The algorithm greatly avoids the local optimization of the algorithm and finds the optimal solution to improve the convergence accuracy.Finally,the proposed CALO algorithm is applied to the optimization of antenna array,and different condition parameters are selected for different topology linear array antennas(LAA)and circular array antennas(CAA),such as,the choice of First Null Beamwidth(FNBW),nulls at prescribed locations,etc.The excitation amplitude and element spacing are optimized for LAA and CAA with different number of elements.From the optimization results,we can see that the results of CALO algorithm and other meta heuristic algorithms are applied to the comparison of antenna arrays.It can be obtained that the CALO algorithm has obvious advantages,and the antenna array sidelobe peak(SLL)reduction is far lower than other optimization algorithms,and the maximum degree of suppression of SLL.