Diagnosis Of Failed Elements In Antenna Arrays Based On Far-field Pattern Samples

Array antennas are working in several applications such as sonar, radar and communications. The antenna, in such cases, has several hundreds of radiating elements or subarrays, Most of them include T/R active network, if part of the component failure will result in failure of the array element, thus increased the side lobe and caused the deterioration of the antenna radiation pattern. even affected the normal use of the antenna.At this moment diagnosis the failed element and make the use of the advantage of active phased array antenna which can recovery radiation pattern by changing their incentive distribution was very important.At present, The method for diagnostic of an array often be used was the near-field diagnosis. Although near-field scanning was accuracy, but it take for a long time, and,in many cases, the array can not be measured by near-field diagnosis. Therefore diagnose the failed element of phased array antenna only by far field amplitude pattern data and then calibration the array with failed element is of great significance.First, We compared variety analysis method of diagnosis failed element in phased array antenna.and select genetic algorithm to solve the diagnosis problem. In that,using a cost function, the method compares the measured radiation pattern with that corresponding to the array with a given configuration of failed/unfailed elements.Genetic algorithms is been used to find the location and number of array elements in the array by find the incentive of array which is most closeed to measurement pattern.In order to improve the success rate of diagnosis, adaptive genetic algorithm with elitist strategy are used in the modeling of genetic algorithms. And through add mutual coupling effects between array antenna in the calculation of the the pattern in objective function which further improved the success rate. Respectively, from a linear array and planar array. Through simulation results form simulation software demonstrate the improved genetic algorithm combined with mutual coupling effects will improve the success rate of diagnosis.Then, Analysis the calibration methods of the array when there have failed elements exist in the array.We also use genetic algorithms thought thinning array and change the excitation of element to improve the performance of a 32 elements and 100 elements taylor calibrated array with failed elements respectively.It is a usefulexploration of how to improve the antenna performance when there have failed elements in the array.Finally, We design a microstrip dipole antenna array, and setting failed elements artificially, and then measured far field pattern in anechoic chamber. Using the actual measured data validate the method mentioned in the article also can achieve well results in the actual engineering applications.