Research On Millimeter Wave Beam Scanning Flat Array Antenna Based On Continuous Transverse Stub

With the rapid development of modern radar and wireless communication technologies,electronic devices are moving toward miniaturization and integration.For instance,with the commercialization of the 5G technology in the near future,the low-cost,low profile and high performance antennas at 6-43 GHz,V-and E-bands are become an urgent issue.Continuous transverse stub(CTS)array antennas are a good candidate for advanced antenna systems,especially for millimeter wave applications.This thesis proposes some designs of CTS array antenna,including high-gain,low-sidelobe and beam-scan array antennas.The main contents of this thesis can be summarized as follows:(1)A CTS array antenna with high gain,low sidelobes and cross-polarization characteristics is proposed.The antenna consists of a full-corporate feed 32-slot CTS array covered with a 45° linear polarizer.A multiple-aperture excited parallel-plate waveguide(PPW)structure works as the linear source generator(LSG)to generate the quasi-TEM wave with uniform amplitude distribution over the whole operating band from 71 to 86 GHz.The 45°linear polarizer contains two layers of slots,the array antenna achieved the low cross-polarization and side-lobe level(SLL),while maintaining high aperture efficiency.For demonstration,one prototype is designed,fabricated and measured.Measurement results show that the far-field SLLs nearly satisfy the ETSI class-IV envelope standard.The antenna has an aperture efficiency of over 74% with the peak gains of better than 37.9d Bi.Over the entire frequency band,the cross-polarization is suppressed to below-41 d B.(2)A frequency-scanned antenna based on CTSs for beam steering applications is presented.The hollow-waveguide CTS radiation slots are fed by a wideband quasi-TEM LSG.In order to increase the scanning angle,a non-uniform zigzag line slow-wave structure is employed underneath the radiation slots to control the phase distributions.The beam direction is tunable with varying frequency.To validate the design,a prototype array is designed and simulated.The simulation results show that hat the proposed array has an impedance bandwidth of-15 d B from 26 to 34 GHz.The peak gain is 25.1-26.2d Bi and the radiation angle can be scanned from-30° to 30°.Over the entire frequency band,the first sidelobe is suppressed to below-12 d B.(3)A multi-beam CTS antenna based on butler matrix(BM)is proposed.The multibeam beamforming network is realized with a BM.The CTS array radiates energy into free space through four radiating slots.Combined with these structures,the CTS multi-beam antenna based on BM is designed and simulated.The simulation results show that the reflection coefficients of ports 1,2,3 and 4 are all lower than-12 d B from 28 to32 GHz,and the isolation is close to-15.d B,the simulated gain of each port at 28 GHz is 15.6,12.1,12.0,and15.8d Bi,respectively.The proposed antenna also possesses wide angle coverage of ±40° with good steerable radiation.