Investigations On Substrate Integrated Waveguide Slot Antennas And Arrays

As a planar intergrated waveguide structure,the substrate integrated waveguide(SIW)combines the advantages of traditional metal waveguide and microstrip transmission lines.The antenna based on SIW also has the advantages of easy processing,low loss,and high integration.This thesis aims at the application of 24 GHz miniatuturized SAR imaging radar,and focus on SIW slot antennas and arrays,including slot standing wave array and filtenna based on slot structure.The dissertation is organized as follows:Firstly,Theoretical basis of SIW slot antenna and filter antenna are introduced.The structural characteristics and equivalent analysis methods of SIW are introduced,and the guided wave characteristics of SIW are analyzed.Then the radiation principle of SIW slot structure is discussed.Based on Elliot's classical waveguide slot theory,the radiation characteristics and parameter extraction of SIW wide-side longitudinal slot elements are analyzed,and the comprehensive method of wide-side longitudinal slot arrays is analyzed.Finally,the coupling matrix,parameter extraction and design method of the SIW slot structure coupled resonant filter antenna are introduced.Secondly,a SIW slot antenna array is designed for a small synthetic aperture radar(SAR)whose working frequency is 24 GHz ? 24.5GHz.The antenna design background and index requirements is introduced,and the design scheme is determined.Then,the single-slot parameters were modified,and a 1 × 10 one-dimensional Taylor-distributed low-sidelobe linear array was designed based on the slot array synthesis method and Taylor distribution theory.Combining the 1 × 10 linear array with a SIW power divider and a transition structure between SIW and a microstrip structure,a 2 × 10 slot array antenna is designed.The measured return loss of the antenna at the working frequency of 24 GHz ? 24.5GHz is below-15 d B.The distance direction beamwidth of each frequency point in the working frequency band is within 35 ° ?40 °,and the azimuth direction beamwidth is within 12 ° ? 15 °.The gains are all above 14 d B,the isolation of the transmitting and receiving antennas are below-40 d B,all the antenna specifications meet the requirements.In order to suppress out-of-band spurs and improve system performance,the third part further studies the SIW slot structure filter antenna in the 24 GHz band.A method based on the combination of parameter extraction and spatial mapping was used to design a SIW-based filter and a SIW slot filter antenna unit and array.The coupling matrix of the filter and the filter antenna is analyzed,and the ideal filter response is synthesized.Then,the coupling coefficient,external quality factor and radiation quality factor are extracted to determine the initial parameters of the device,finally,bring the simulation results of the initial model into ADS for rough model mapping,extracting the coupling matrix of the entire model,comparing with the ideal matrix,determining the adjustment direction of the size parameter.According to iterative optimization,a filtering antenna and and filter close to the rational filter response can be obtained.The experimental results are basically consistent with the simulation design results,and the comprehensive response characteristics after filtering and antenna fusion are verified.