Research Of Leaky Wave Antenna Based On Substrate Integrated Waveguide For 2D Beamforming

In recent years,with the rapid development of mobile communication,beamforming antenna which can achieve uniform coverage of wireless signal has been widely concerned.Substrate integrated waveguide leaky wave antenna is widely used in the research of beam forming antenna because of its low profile and easy integration.However,the current beamforming antenna is mainly one-dimensional beamforming,which is only suitable for one-dimensional long straight confined space.In order to achieve uniform radio wave coverage in indoor and other two-dimensional space,it is necessary to design two-dimensional beamforming antenna.In this paper,according to the practical application requirements of two-dimensional beamforming antenna,the radiation characteristics of annular substrate integrated waveguide leaky wave antenna and its array are studied.On this basis,its application in two-dimensional beamforming is explored.The main innovation of this paper are as follows:1.An annular substrate integrated waveguide leaky wave antenna is studied,which radiates the-1st harmonic and etches rectangular slots.The results show that the circular substrate integrated leaky wave antenna can generate conical beam under-1st harmonic radiation;The slot size affects the omnidirectivity of the azimuth plane of the tapered beam,the slot period affects the pitch angle of the tapered beam,and the slot period and the waveguide size jointly determine the axial ratio characteristics of the azimuth plane of the tapered beam;It is difficult to achieve omni-directional circularly polarized coverage in the azimuth plane for the annular substrate integrated waveguide leaky wave antenna with rectangular slot.2.A new structure of leaky wave antenna based on-1st harmonic radiation and etched circular slot is proposed and designed.Firstly,the radiation characteristics of the antenna radiation layer are studied under the condition of ideal waveguide feeding,and then the feeding layer is designed with coaxial probe feeding and slot coupling feeding.The results show that the size,offset and period of the circular slot affect the radiation beam and polarization characteristics of the antenna;The slot coupling feeding method is more suitable for the annular leaky wave antenna studied in this paper.The test results are in good agreement with the simulation results,which shows the effectiveness of the design and lays a foundation for further research on the double ring substrate integrated waveguide leaky wave antenna array.3.The radiation characteristics of annular traveling wave slot array are studied by using single slot surface field continuation and far-field integration method.Firstly,the theoretical modeling and analysis of the single ring traveling wave slot array are carried out,and the effects of slot period,offset and waveguide size(waveguide radius or number of transmission waveguide wavelengths)on the radiation characteristics of the single ring substrate integrated waveguide leaky wave antenna are studied.Then,the radiation characteristics of the double ring traveling wave slot array are analyzed by combining with the beam weighted superposition method,Finally,the two-dimensional beamforming design method is summarized.The research results show that the twodimensional beamforming types of dual annular traveling wave slot array are: single polarization tapered beam switching,multi polarization tapered beam switching,lobe separation and scanning,single polarization two-dimensional cosecant beamforming,multi polarization two-dimensional cosecant beamforming.4.A leaky wave antenna array based on double annular substrate integrated waveguide is proposed and designed,which can realize two-dimensional beamforming.According to the summarized two-dimensional beamforming design method,five kinds of beamforming effects of the double annular substrate integrated waveguide leaky wave antenna array are realized.Two kinds of antennas which can realize the single cone beam switching and lobe separation are processed and tested,and the effectiveness of the twodimensional beamforming design method is verified.