Research And Design On Millimeter Wave Antenna Based On Substrate Integrated Waveguide

With the rapid development of the mobile Internet and the Internet of Things,the traditional mobile communication systems have become increasingly unable to meet people's requirements,so the 5G mobile communication system has been put on the agenda.The 5G mobile communication system has new characteristics such as theoretical transmission rate of 10Gbits/s,extremely high channel capacity and power capacity,and transmission delay lower than 1ms,which promote the birth of numerous new technologies for 5G.The millimeter-wave technology is the most effective and innovative technology among the many 5G technologies.The traditional mobile communication bands below 3GHz are becoming crowded increasingly,while millimeter-wave band resources are far from being fully exploited.Moreover,the devices working in millimeter-wave band have the advantages of light weight and small volume,which promote the development of the millimeter-wave systems toward miniaturization and modularization.The millimeter-wave has many advantages in communication,but the high path loss of the millimeter wave limits the practical applications.So the array with high gain is the firstly recommendation in the design of the millimeter-wave antenna.Furthermore,the millimeter-wave has multiple frequency bands assigned to 5G communication,and the Ka-band can be allocated for frequency division duplex communication,so the dual-band antenna is one of the research hotspots of the 5G millimeter-wave antenna.In addition,the millimeter-wave possesses the characteristics of short wavelength and many reflection components,which leads to serious"multipath effect".The circularly polarized antenna has the advantages of anti-multipath effect and polarization match,which has become a research hotspot.The microstrip antenna is easy to realize the characteristics of dual-band and circular polarization,but the loss of the microstrip in the millimeter-wave band is too large,so it does not meet the practical requirements of millimeter-wave communication.The SIW is the first choice for millimeter wave antenna because it retains most of the merits of the metal waveguide and the characteristics of low profile.In the thesis,a dual-band cavity-backed slot array based on SIW is proposed to cover the bands of 28GHz and 38GHz in 5G communication.The TM₀₂₀ mode and the TM₁₂₀ mode in the SIW circular cavity are excited by proximity-coupled slot,which solves the key issues of"multi-frequency resonance"and"proper frequency ratio".Moreover,the proximity-coupled slot can suppress the polarization degeneracy mode in the circular cavity.Finally,a power division network based on SIW is designed to form a 2×2 array.The measured results show that the operating frequency range of the array is 26.3GHz-32.3GHz and 37.4GHz-38.4GHz,which covers 28GHz and 38GHz frequency bands.The measured gains at the28GHz and 38GHz are 13.2dBi and 14.6dBi,which are suitable for 5G applications.In addition,the proposed antenna provides a guiding idea for the multi-frequency implementation principle of the same type of antenna.For the issues of“multipath effect”and“polarization mismatch”in millimeter-wave,a 4×4 cavity-back slot array working at 28GHz is proposed.The circular polarization characteristics are realized by using a SIW-based two layers sequential rotating feed structure excitation 2×2 subarray.In order to verify the radiation effects of large array expanded by the subarray,it is expanded into a 4×4 array.The measured results show that the array antenna has an AR impedance of 14.5%?25.6-29.6GHz?.Moreover,the peak gain is 20.5dBic at 28GHz and the radiation efficiency of the proposed array is greater than 88%in the operating bands.The array has advantages of low profile,compact structure,simple design,high radiation efficiency and wide axial bandwidth,which is suitable for high gain circularly polarization applications in 5G millimeter waves.