| Dual-beam leaky-wave antenna(LWA)based on Spoof Surface Plasmon Polaritons(SSPPs)in terahertz band is classified as a traveling wave antenna.Because it has the advantages of strong directivity,high radiation efficiency and miniaturization,it is widely used in the fields of high-resolution radar and real-time spectrum analysis,and has become a research hotspot in recent years.In this thesis,dual-beam leaky-wave antenna based on SSPPs in terahertz band is investigated.The major results of the research are as follows:Firstly,the basic characteristics of the traditional SSPPs unit structure are analyzed,and a double-sided U-slot structure in terahertz frequency band is given.Based on the unit structure,a SSPPs waveguide in terahertz frequency band is given.A novel dualbeam leaky-wave antenna is proposed by introducing a geometric inversion structure into the transmission line.The results show that the antenna successfully excites two beams in the frequency band of 0.23 THz to 0.29 THz.The scanning angle of the forward beam ranges from +16° to +57° and the scanning angle of the backward beam ranges from-64° to-8°.A total of 97° scanning angle and an average gain of about 10 dBi are achieved in the given operating frequency band.Secondly,in addition to the inversion modulation,through the study of H-slot in terahertz band,we introduce a sinusoidal modulation on the surface impedance,and propose a single-beam LWA in terahertz band.In the frequency band of 0.5THz to0.6THz,the beam sweeps through 60° to 84° with a total range of 22°.At the same time,the open stopband phenomenon occurs in the periodic structure.However,the open stopband can be effectively suppressed by/4 displacement,and the simulation results are consistent with the design theory.It was shown herein that the main beam of the LWA with open stopband suppression can be scanned from +7° to +94° with an average gain of 16.4dBi in the band of 0.58 THz to 0.66THzFinally,based on the sinusoidal modulation theory,we introduce two different periods of sinusoidal modulation on the upper and lower sides of the waveguide.Through the design of the depth of the two grooves,two beams are successfully excited in the far-field radiation of the antenna.In the frequency range from 0.45 Thz to 0.55 Thz,the scanning angle of the forward beam ranges from +39° to +70° and the scanning angle of the backward beam ranges from 105° to 122°.By changing the period length or groove depth of sinusoidal modulation,the two beams can be controlled separately,which provides a new possibility for the design of dual-beam leaky-wave antenna. |
PDF Full Text Request