Research On Circular Polarized Dielectric Resonator Antenna And Substrate Integrated Waveguide Array Antenna

With the rapid development of wireless communication,radar navigation,satellite meteorology and other systems,the application scenarios of antennas have also increased,so higher requirements are put forward for the performance of antenna such as circular polarization,frequency band width,and gain,and the trend of low-profile,miniaturization and easy integration is developed under the premise of ensuring antenna bandwidth,radiation power and efficiency.Circularly polarized antennas are less affected by antenna offset and propagation effects,have strong anti-interference ability,and have important applications in electronic countermeasures and detection.Compared with microstrip patch antennas,dielectric resonator antennas have the advantages of high dielectric constant,low loss,high radiation efficiency,and diverse shapes.For the current Internet era,the frequency band resources of microwave frequency bands（less than 30 GHz）are tight,and millimeter wave frequency bands（30-300 GHz）with more spectrum resources have attracted widespread attention from today’s scholars,and many popular application systems,such as satellite communications,vehicle radar,electromagnetic imaging,etc.,have turned to millimeter wave frequency bands.In the potential millimeter wave band,Q-band communication has been the focus of research as one of the research bands for developing 5G mobile communication.Substrate integrated waveguide（SIW）has the characteristics of low loss and easy integration,and is widely used in the research of microwave and millimeter wave array antennas.Therefore,it is of great application value to study the broadband circularly polarized dielectric resonator antenna and the circularly polarized array antenna fed by the Q-band substrate integrated waveguide.In this thesis,the research on the above two items has been implemented,and the achievements are as follows:（1）A novel circularly polarized antenna with a chamfered and stair-shaped dielectric resonator（CSDRA）is presented,which introduces a chamfer in the stair-shaped resonator structure.This antenna uses a dielectric resonator as a radiation unit and uses a microstrip slot coupling feed method.By slotting on the floor to obtain more modes suppressed by the floor,a second axial ratio resonance point is excited,expanding the bandwidth.By adjusting the relative position of microstrip line and stepped dielectric resonator,the broadband circular polarization characteristics can be realized.By choosing the appropriate position and adjusting the size of the tangent angle,the bandwidth of circular polarization can be expanded.The electromagnetic simulation software HFSS is used for simulation analysis.Simulated results show that the CSDRA has 10 d B return loss of 69.7%（3.91-8.10 GHz）and 3 d B axis ratio（AR）bandwidths of51.4%（3.87-6.55 GHz）,respectively,and thus useable bandwidth of 50.4%（3.91-6.55GHz）is obtained.The achieved gain in the working frequency band is 3.35-3.85 d Bic.The antenna has the advantages of simple structure,high degree of integration,easy manufacture and good radiation performance,and thus can be applied to the field of wireless communication.（2）A low-profile right-handed circularly polarized（RHCP）array antenna operating in Q-band is designed,which is fed by substrate integrated waveguide（SIW）.The antenna adopts a double-layer printed circuit board structure,which consists of a substrate integrated waveguide feed unit at the lower part and a dielectric substrate in the middle,and a radiation unit composed of 16 hollow square patches（HSPs）at the top.The radiating units are divided into four groups and evenly distributed in a square array.The right-handed circularly polarized wave is generated by the annular microstrip radiation patch unit with the top corner cut;the four connected patches get the same power through the I-shaped power divider,and the impedance matching is adjusted by the Y-shaped impedance matcher.By adjusting the tangent angle,the return loss bandwidth and the axial ratio bandwidth can be matched.The simulated results by using HFSS and CST show that the relative impedance bandwidth of the antenna is 41.2 GHz-42.1 GHz,and the circular polarization bandwidth is also 41.2 GHz-42.1 GHz.The gain in the working frequency band exceeds 16.1 d Bic,and the radiation efficiency is not lower than 91%.The antenna has the advantages of simple structure,easy fabrication,low profile（less than 0.1λ₀）and good orthogonal polarization discrimination,and has potential application value for 5G wireless communication systems.