| Spoof Surface Plasmon Polaritons(spoof SPPs)are an extension of the optical band surface plasma excitons(SPPs)in the microwave and terahertz bands,which have similar dispersion characteristics.Spoof SPPs have the advantages of dispersion characteristics and the ability of the constrained electromagnetic field to be easily controlled by structural parameters.Spoof SPPs has been widely used in microwave and terahertz band passive devices since its inception.This thesis investigates the two-dimensional planar spoof SPPs structure with small structure size,easy processing and integration,and applies the planar structure-based spoof SPPs in antenna design.The main research contents and innovative results of the thesis are as follows:1.A sawtooth endfire antenna based on spoof SPPs is proposed.The dispersion characteristics of the spoof SPPs structure and the influence of its structural parameters on the cutoff frequency are analyzed,and the way in which the surface waves in the two-dimensional planar spoof SPPs transmission line are converted to radiate into free space by a gradient conical structure is studied.Based on this,a sawtooth endfire antenna based on spoof SPPs is proposed,which achieves an average radiation efficiency of 85%in 6-13GHz,can cover the entire X-band,has stable far-field radiation characteristics,and has a gain of up to 12.4dBi.The antenna has performance advantages such as simple feeder structure,compact size and easy integration.2.A dual-band frequency scanning antenna based on spoof SPPs transmission line is proposed.The effect of each parameter in the rectangular holes of spoof SPPs on the dispersion characteristics and the frequency band of the spoof SPPs transmission line application was analyzed.The results show that the depths of rectangular hole has a large effect on the cutoff frequency,and etching two rectangular holes of different depths in a metal strip can generate standing waves in the transmission line.Based on this structure,a dual-band frequency scanning antenna is designed by combining magnetic coupling with the principle of leakage radiation.Loading two sets of circular patches of different sizes on both sides of the spoof SPPs transmission line achieves a dual-band frequency sweep of 90°-196°in the 4-9 GHz and 126°-192° in the 16-32 GHz,with sweep angles of 106°and 66°.The antenna achieves a gain of between 10-12 dBi in the operating band with an average radiation efficiency about 90%.The antenna was subjected to processing and tests,the experimental results verified the good frequency scanning characteristics.3.A broadband leaky wave antenna based on spoof SPPs and SRRs was proposed.The performance of spoof SPPs transmission lines with double side notches was analyzed and the high efficiency conversion of the broadband between microstrip lines and spoof SPPs transmission lines was studied.Based on the principle of leakage radiation,the composite right-and left-hand transmission characteristics realized by loading SRR arrays and the broadband characteristics of spoof SPPs slow-wave transmission lines are combined to design a broadband leaky wave antenna with an operating frequency band of 5-14 GHz and a scanning width of 110°.The antenna has a compact construction,good radiation performance and broadband frequency scanning capability. |
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