Leaky Wave Antenna And Endfire Antenna Based On Spoof Surface Plasmon Polaritons

In recent years,surface plasmon polaritons has already achieved a great development,whose electromagnetic field is confined to the near vicinity of the dielectric–metal interface.Generally speaking,the SSPPs mode can be formed by the interaction between free electrons and EM waves around the spoof plasmonic metamaterials.For its advantages of high gain and low profile,the SSPPs TL has a wide application prospect in microwave and terahertz segments.Based on this structure,the traditional theory is applied to design the leaky-wave antenna and endfire antenna.The main research contents and innovations are summarized as follows:1)In this paper,we have a study on the symmetrical SSPPs TL with holes,which is fed by the coplanar waveguide.This conversion achieves a smooth change of the TM mode.It allows the control of EM field distributions by changing the geometrical parameters.At the same time,the proposed spoof SPPs TL is proved to achieve much better transmission performance than the traditional microstrip transmission line with the same geometry.Both the simulation and experiment reveals that the loss in the flexible SSPPs TL is small.2)A novel high gain endfire antenna based on the spoof surface plasmon polaritons(SSPPs)transmission line(TL)is proposed in this paper.The antenna is designed on a groundless single metal layer inherited the advantages of SSPPs.Combined with asymmetric radiation elements of SSPPs TL and an elliptical director,this antenna generates endfire radiation beams with 15.75–17.5 GHz.Although the aperture is small,it has obtained a high gain from 10.5 to 12.1 d Bi and a high efficiency of 95% overall the operating bandwidth.Measurement results agree well with the simulations.The advantages of single-layer,high gain and low profile make its valuable in wireless communications.3)In this part,characteristic mode analysis(CMA)is adopted to analyze and mitigate this novel high gain antenna array,which is based on the SSPPs TL.The mode significance and modal nearfield distributions are proposed to analyze the unit cell.The broadside antenna array is integrated with the SSPPs TL,whose cells are arranged along this transmission line.Both the simulation and experimental results show that this antenna obtains a high gain of 17 d Bi.3)A novel stereoscopic SSPPs leaky wave antenna is proposed in this part,which achieves frequency scanning radiation in the backward.Throughout the periodically-modulated SSPPs TL,the electric energy can be released to feed the metallic patch.As the experimental results,the SSPPs leaky wave antenna achieves the beam scan from 180? to 25?,whose gain keeps above 13 d Bi in the operating frequency of 13.5-18 GHz.