Reciprocity is ubiquitous in antennas for receiving and radiating electromagnetic(EM)waves,i.e.,if an antenna has good receiving performance at a given direction,it also has good radiation performance in that direction.Inspired by this,we propose a method of designing a quasi-ominibearing retro-reflective metagrating(RRMG)protected by the reciprocity of antennas.Based on the second-order mode around 15.0 GHz of a short-circuited structured patch antenna(SPA),incident transverse magnetic waves can be received,channeled into the coaxial lines,reflected by the shortened end,and finally re-radiated into free space with a reversed wave vector.RRMGs are contrived consisting of this identical SPA,with a grating constant allowing±2nd-,±1st-,and zeroth-order diffractions.Oblique incidence,plus the tilted nulls of the re-radiation pattern,can eliminate-1st,zeroth,+lst,and+2nd orders,and only the-2nd order is left to achieve retro-reflections.Prototypes were fabri-cated and measured.Simulated and measured results show that the RRMGs maintain only-2nd-order diffraction for incident angles 32.2°≤θi＜90.0° in four quadrants,and that RRMGs can achieve quasi-omnibearing retro-reflections for θi = 50.0°.The use of higher-order diffraction brings more degrees of freedom in manipu-lating EM waves,and this strategy can be readily extended to millimeter waves,THz wave,or even optical regimes.

YUXIANG JIA;JIAFU WANG;YAJUAN HAN;RUICHAO ZHU;ZHONGTAO ZHANG;JIE YANG;YUEYU MENG;YONGFENG LI;SHAOBO QU

Department of Basic Sciences,Air Force Engineering University,Xi'an 710051,China;Shaanxi Key Laboratory of Artificially-Structured Functional Materials and Devices,Xi'an 710051,China

光子学研究（英文）

[1]YUXIANG JIA;JIAFU WANG;YAJUAN HAN;RUICHAO ZHU;ZHONGTAO ZHANG;JIE YANG;YUEYU MENG;YONGFENG LI;SHAOBO QU-.Quasi-omnibearing retro-reflective metagrating protected by reciprocity)[J].光子学研究（英文）,2022(04):843-854

omnibearing,metagrating,Reciprocity,ominibearing,RRMG,channeled,RRMGs,contrived,diffractions,+lst,and+2nd,Prototypes

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