Design And Implementation Of A Strongly Coupled UWB Phased Array Antenna

Demands for multi-functional devices are becoming more and more urgent in modern radar and communication systems.In order to adapt to this trend,minimized ultra-wideband antennas and arrays have become heated topics in the field of antenna designing.With the goal of ultra-wideband and low-profile phased array,this thesis concentrates on the recently springing-up tightly-coupled arrays.Vivaldi antenna and dipole antenna are discussed as the array element.At the same time,adjusting the parameters of antenna is a complex process in nowadays antenna designing,which also relies too much on the designer's experience.To shorten the designing circle and unify the designing way,this thesis explores a new antenna design and optimization method.This thesis's main work is as follows:The first part studies the tightly-coupled ultra-wideband Vivaldi antenna array.This part introduces the uniform design method of ultra-wideband antenna array and how the Vivaldi unit's size affects the performance of array.Array made up by this unit shows ten octave bandwidth and good scanning performance.On the basis of above,this part designs a low-profile Vivaldi antenna array and an all-metal Vivaldi antenna array which is easier for fabrication.The second part studies the tightly-coupled dipole and fragmented antenna array.This part introduces a tightly-coupled dipole array with three octave bandwidth and a minimized balun to feed the array.To cover the shortage of traditional antenna design method,this part presents a novel method which combines the genetic algorithm with electromagnetic simulation software.Using this method,the dipole array above is optimized to show a five-octave bandwidth.