Research On Design And Application System Of High-Performance Substrate Integrated Waveguide Antennas

With the rapid increase of the electronic devices,the low-frequency spectrum resources become more and more crowded,which leads to more and more wireless systems using the antennas working in higher frequencies(X-,Ku-,K-,Ka-band,etc.)to complete the interaction and transmission of information.The substrate integrated waveguide structure has attracted extensive attention in the design of the higher frequency antennas,because of its characteristics of low insertion loss,low radiation interference,easy processing and easy integration with circuits.Based on the substrate integrated waveguide structure,taking the cavity mode,low-frequency cut-off characteristics and surface current distribution of the structure as the design bases,and taking the excitation cavity mode,form of loading slot,bending branch and printing gradual transition structure as the main design means,the design methods of broadband,dual-band,circular polarization and high-gain of the antenna is studied in this dissertation.In the novel measurement system requiring the lightweight probe antenna,the feasibility of using the substrate integrated waveguide horn antenna to replace the traditional metal horn antenna is explored,and its application performance in the actual scene is compared and analyzed,expanding the applicable field of the substrate integrated waveguide antenna.The main works and the research contents of this dissertation include the following four aspects:1.The design method of the high-performance cavity-backed slot antennas based on the combination of the substrate integrated waveguide cavity mode and the slot structure is explored.In the design,the cavity mode is analyzed first,then the slot structure is used to excite the resonance based on the mode characteristics,and finally the required cavitybacked slot antenna is realized.Based on the above design ideas,two cavity-backed slot antennas are designed in this dissertation.For the broadband cavity-backed slot antenna,the modified dumbbell-shaped slot and the grounded coplanar waveguide feeding structure are used to make the various resonant modes(TE310 even mode,TE310 odd mode,TE310 and TE120 hybrid mode,TE320 and TE120 hybrid mode)close to each other,so as to broaden the impedance bandwidth of the antenna.The measured results show that the proposed antenna obtains an impedance bandwidth of 26.7% and a peak gain of 9.5 d Bi.For the dual-band cavity-backed slot antenna array,through the analysis of the cavity modes(TE110 and TE120modes),a pair of C-shaped and rectangular slots are introduced,and the arrangement of slots is optimized,so as to realize impedance matching in the frequency bands near 28 GHz and38 GHz.Finally,the design of compact 2×2 element dual-band antenna array is realized.The measured results show that the antenna array obtains a peak gain of 12.3 d Bi and 13.6 d Bi in two operating bandwidths respectively.2.The design method of the broadband circularly polarized radiation performance of the substrate integrated waveguide cavity-backed antenna using bending strips is studied.The bending strips contribute the orthogonal polarization field components,which is helpful to produce a circularly polarized radiation beam.For the dual-band dual-polarized sharedaperture antenna,a 24.25-27.5 GHz circularly polarized antenna array based on the bending strips is designed first.Secondly,based on the concept of structural reuse,the low-frequency(3.3-3.6 GHz)line polarization antenna is designed by using the slot coupled microstrip antenna loaded with the parasitic strips.By optimizing the position of antenna and radiation structure,and relying on the approximate closed structure and low-frequency cut-off characteristics of substrate integrated waveguide,the isolation between the two antennas is improved,the interaction between the two antennas is reduced,and the design of dual-band dual-polarized shared-aperture antenna suitable for 5G equipment is realized.In the design of the low-profile circularly polarized antenna array,the application scenario of the bending strips is further expanded.Two circularly polarized resonant frequency points are introduced through the four bending strips,so as to complete the design of the low profile broadband circularly polarized antenna element.The design of the antenna array is realized based on the sequential rotating feeding network to further improve the circular polarization radiation performance.The measurement results show that the antenna array achieves an operating bandwidth of 11.9% and a peak gain of 14.2 d Bic.3.The design method of the broadband high-gain end-fire antenna based on the printed gradual transition structure is studied,and two antenna arrays are designed.The current phase difference between the upper and lower surfaces of the opened-end of the substrate integrated waveguide is 180°,so it can be regarded as a broadband balun structure.While the printed gradual transition structure can gradually improve the impedance matching characteristics with the free space,which lays the foundation for the wide impedance bandwidth of the end-fire antenna.For the end-fire circularly polarized antenna,the printed gradual metal strips which can radiate the vertical polarization wave and adjust the amplitude ratio and phase difference of two orthogonal polarization field components are introduced between the substrate integrated waveguide feeding structure and the horizontal polarization antenna,so as to realize the broadband circular polarization end-fire radiation characteristics.Based on the substrate integrated waveguide feeding network with low insertion loss and radiated interference,a 1×8 high-gain antenna array is realized.The measured results show that the proposed antenna array achieves an operating bandwidth of 14% and a peak gain of16.3 d Bic.For the high-gain end-fire antenna,the structural form of the traditional printed transition element is improved,and the high refractive index metamaterial slabs are loaded on both sides of the antenna element to further improve the gain.Finally,the 1×4 antenna array is designed.The antenna and array have achieved excellent performance such as broadband,high-gain,low cross-polarization and stable patterns.4.A new measurement system based on the substrate integrated waveguide horn antenna is designed.Based on the requirements of the measurement system for lightweight,miniaturization and high-performance of probe antenna,this dissertation focuses on the design of the substrate integrated waveguide horn antenna with broadband,wide-beam and low cross polarization by using multi-layer stepped flared groove structure.On this basis,through the design of electromagnetic protection,instrument control and sampling solutions of the system,a new measurement system based on the substrate integrated waveguide horn antenna and suitable for the pattern measurement of large antenna array is finally built.Furthermore,the application performance of the proposed horn antenna and the traditional metal horn antenna in the new measurement system is compared.Finally,the advantages of the proposed measurement system and the substrate integrated waveguide horn antenna are verified,the application range of the substrate integrated waveguide antenna is expanded,and the design and research of a novel measurement system is realized.