Design Of Broadband Tightly Coupled Array

Ultra-wideband phased array technology is a hot topic in the field of antenna research and has received extensive attention from scholars.The tightly-coupled array antenna is a new type of broadband array antenna proposed in recent years.It uses the coupling of neighboring cells,adding the floor,and covering the dielectric layer to achieve bandwidth expansion.It not only has ultra-wideband characteristics,but also has a wide scanning angle.Low profile,easy to conformity advantage.This article studies and designs the tightly coupled array antenna.The details are as follows:Study the basic theory of traditional phased arrays,analyze the radiation principle of one-dimensional linear arrays and two-dimensional arrays,and the relationship between the two;explore the principles and methods for widening the bandwidth of tightly coupled arrays,starting from the Smith chart,for bandwidth The principle of broadening is analyzed step by step;starting from the definition of the Fourier series,the relationship between the infinite period array and the Floquet series is analyzed,the Floquet series of an infinite period array is deduced,and then an infinite period array single mode transmission is proposed(No grating lobe)conditions;By designing the array unit as an indicator,the unit is divided into two and the common mode resonance point between the units is moved out of the working bandwidth range,and a balun structure is used for feeding.Then,the unit port is reduced by the power divider to achieve the purpose of reducing the TR component.The design unit meets the requirements for a bandwidth of 2-12 GHz,a VSWR of less than 2.8,and a scan angle range of ±45°.The truncation effect of tightly coupled arrays is analyzed.The performance of tightly coupled arrays is degraded due to the truncation effect.In order to reduce the effect of truncation on finite arrays,4×4 arrays for resistive truncation compensation and open and short truncation truncation compensation are analyzed and compared.The advantages and disadvantages of this kind of truncation method;through the 1×16 linear array analysis principle of array scanning,the problem of the close-coupled array scanning was initially investigated.Finally,the 8×8 array is designed and simulated.When the array is axially radiated,the active VSWR does not exceed 3 in the operating band.