Study And Design Of Antenna Arrays Based On Substrate Integrated Technology

Millimeter wave microstrip patch antenna has received extensive attention all over the world due to its prominent advantages in short wavelength,wideband,small dimension since it was first invented,and it has played an important role in aerospace craft and rader system.Due to rader system must measure wide angular range accurately and fastly,which will require the antenna’s ability in generating multi-beam simultaneously in order to trace quickly.Therefore,the feature of the intelligent beam antenna control is becoming a hot spot of current research and focus.Reconfigurable antenna as a new kind of antenna,compared with the traditional antenna,it has the advantages of smaller size,lighter weight and to achieve diversity.Owing to reconfigurable antenna thus,the design of antenna being diverse,the traditional design of antenna and array antenna are expanded.As a result,it offers a huge potential and broad prospects for development for enhancing antenna and array feature.This thesis focuses on reconfigurable antenna,based on Substrate Integrated Coaxial Line(SICL)theories,in which the multi-beam antenna array are researched,a Q-band microstrip reconfigurable patch array antenna using Liquid Crystal Polymer(LCP)technology and a switched-beam antenna with reduced sidelobe fed by modified Butler matrix using Substrate Integrated Coaxial Line(SICL)are designed in this paper.The corresponding contents are as follows:(1)A Q-band 5×4 microstrip reconfigurable antenna array is designed.The structure based on PIN tube control switch circuit,which including two way one points two parallel feed network and four column series feed antenna unit,each column contains 5 rectangular patch antenna.The traditional shunt feed network suffers from high insertion loss at high frequency,so the proposed series/shunt feed structure can improve the insertion loss to some extent.(2)Studied the theory of Substrate Integrated Coaxial Line(SICL),and design the Ground Coplanar Waveguide(GCPW)to SICL adapter.Meanwhile,design the SICL 3 db directional coupler,cross coupler structure and Butler matrix,and gives the relevant analysis of the simulation data.And also simulated the structure of the SICL slot array antenna.(3)A Ka-band beam forming network based on SICL 4×8 Butler matrix is designed.Low sidelobe level cannot be optained due to the fact that the traditional 4×4 Butler matrix,which provides equal power at all four output ports.In four output ports cascade respectively SICL T-junction unequal power divider,in preparation for the subsequent low sidelobe antenna design.(4)A low sidelobe level array antenna is designed at Ka-band based on SICL.The array is composed of eight columns SICL slot antenna array structure,using cross coupler based on the Butler matrix feed network in section(3),by designing a suitable power split,the signal amplitudes of the eight output ports decrease,moving from the centre elements towards edge ones that low sidelobe level of the entire array can be obtained,and the simulation results show that the multi-beam antenna in four beam deflection can keep SLL<-15dB.