Study On Low Sidelobe Ridge Substrate Integrated Waveguide Slot Array Antenna

Nowadays,the tendency of radar and communication system is small size,low cost,high integration and high performance.Substrate Integrated Waveguide(SIW)has the advantages of both traditional metallic waveguide and microstrip planar circuit.It has attracted intensive attention because of its small size,light weight,low cost and easy integration.Ridge substrate integrated waveguide is a novel waveguide structure based on substrate integrated waveguide,and it has broader bandwidth and smaller size.In this thesis,a parametric study of the Ridge Substrate Integrated Waveguide(RSIW)performance and bandwidth is discussed.The design method of traditional metallic waveguide slot array antenna was used for the design of SIW slot array antenna as well as RSIW slot array antenna.Low sidelobe features are achieved based on this design method and the bandwidth of RSIW slot array antenna became broader.The whole thesis includes the following part:Chapter 2 briefly introduced the principle,propagation features and design steps of SIW.A parametric study and optimization of SIW performance is discussed.The design methods of microstrip balun is introduced and a better performance of microstrip balun feed SIW is designed based on this method.Chapter 3 briefly introduced the principle of slot antenna and the design method of traditional metallic waveguide slot array antenna.A new method of getting the slot parameters is given and a low sidelobe SIW slot array antenna is designed based on this method.The sidelobe is lower than-25 d B,and a 5% bandwidth is easily achieved.Chapter 4 briefly introduced the principle and propagation features of RSIW.A electromagnetic simulation software HFSS is used to analyze the effect of the RSIW parameters to its cutoff frequency of its fundamental mode and the second mode.A well performance RSIW is designed considering mechanical processing.A novel feed structure is designed and it has simpler structure and easier integration compared with the existed feed structure.The RSIW has better performance using this feed structure.Chapter 5 presents the method of getting the slot active admittance of RSIW referring to Chapter 3.The electric field intensity is controlled by adjusting the length and offset of the slots and the low sidelobe RSIW slot array antenna is finally designed.The sidelobe is lower than-25 d B,and an 8% bandwidth is easily achieved.