Ultrabroadband Diode-Like Asymmetric Transmission and High-Efficiency Cross-Polarization Conversion Based on Composite Chiral Metamaterial

Transcription

1 Progress In lecromagnecs Research, Vol. 160, , 2017 Ulraroadand Dode-Le Asymmerc Transmsson and Hgh-cency Cross-Polarzaon Converson Based on Compose Chral Meamaeral Yongzh Cheng 1, *, Jngcheng Zhao 2, Xuesong Mao 1, and Rongzhou Gong 3 Asrac In hs paper, a hree layer compose chral meamaeral (CCMM) s proposed o acheve dode-le asymmerc ransmsson and hgh-ecency cross-polarzaon converson y 90 polarzaon roaon wh ulraroadand range n mcrowave regon, whch was vered y smulaon and expermen. Ths CCMM s composed o a ds-spl-rng (DSR) srucure sandwched eween wo wsed su-wavelengh meal grang srucures. The smulaon agrees well wh expermen n prncple. The smulaon resuls ndcae ha he ncden y(x)-polarzed wave propagaon along he z(+z) drecon hrough he CCMM sla s sll lnearly polarzed wave wh hgh pury, u he polarzaon drecon s roaed y ±90, and he polarzaon converson rao (PCR) s greaer han 90% n he requency range o GHz. In addon, n he aove requency range, he asymmerc ransmsson coecen (Δ ln ) and he oal ransmance (T x )orx-polarzed wave propagaon along he z axs drecon are oh over. Fnally, he aove expermen and smulaon resuls were urher vered y he elecrc eld dsruon characerscs o he CCMM un-cell srucure. Our desgn wll provde an mporan reerence or he praccal applcaons o he CCMM or polarzaon manpulaon. 1. INTRODUCTION Chral meamaeral (CMM) s an mporan suse o meamaerals (MMs), he un-cell srucure o whch canno e supermposed ono s mrror mage [1 8], resulng n a cross-couplng eec o he elecrc and magnec eld. Snce he mrror symmery o un-cell s roen eher n he perpendcular plane or n he propagaon drecon, numerous ousandng elecromagnec (M) properes o he CMMs can e acheved, such as negave reracon [3 8], gan opcal acvy [6, 7, 9] and crcular dchrosm [8, 10], asymmerc ransmsson (AT) eec [11 15], and polarzaon converson or roaon [16 19]. specally, manpulang and conrollng he polarzaon propery o M waves usng CMMs s o cenral neres, whch also aracs grea aenon ncreasngly [16 28]. The AT eec was rsly oserved and demonsraed y Fedoov e al. n 2006 [11], whch s one o he mos remarale applcaons o CMMs [29 46]. The AT eec, as a novel phenomenon or he CMMs, orgnaes rom he derence n oal cross-polarzed ransmsson waves propagang n wo oppose drecons [12]. I s smlar o elecronc dode eec ha can loc he elecrc curren n one drecon whle allowng o low hrough he dode n he oppose drecon. The AT eec s rrelevan o he nonrecprocy o he Faraday eecs, whch can happen n he asence o magneo-opcal meda [13 15]. ssenally, he AT eec rgorously oeys Lorenz s recprocy [33], whch can e explaned y de Hoop recprocy Receved 13 Sepemer 2017, Acceped 24 Novemer 2017, Scheduled 18 January 2018 * Correspondng auhor: Yongzh Cheng (chengyz@wus.edu.cn). 1 School o Inormaon Scence and ngneerng, Wuhan Unversy o Scence and Technology, Wuhan, Hue , Chna. 2 School o lecroncs and Inormaon ngneerng, Behang Unversy, Bejng , Chna. 3 School o Opcal and lecronc Inormaon, Huazhong Unversy o Scence and Technology, Wuhan , Chna.

2 90 Cheng e al. and descred usng he Jones marx [14, 15]. AT s very useul n realzng dode-le eec and M polarzaon manpulaon devces such as solaors and polarzaon converors [34 37]. Hence, he AT eec o crcular and lnear polarzaon waves has eng exensvely suded, and varous CMM srucures have een proposed and demonsraed rom mcrowave o opcal requency range [29 46]. A early sage, a -layered CMM n he near-nrared regon was proposed and demonsraed y Menzel e al., whch could acheve only a magnude o 5 or lnear polarzaon waves wh a sngle and [29]. Then, Kang e al. heorecally demonsraed ha a specal CMM reang he symmery n he propagaon drecon could realze he AT eec or lnear polarzaon wave, and he magnude o AT parameer could acheve 5 [30]. However, could only wor wh a sngle and. Susequenly, a hn CMM comned wh he M wave unnelng was proposed, whch could realze a near uny magnude o AT parameer wh a dual-and [33]. Aer ha, an ncreasng numer o CMM srucures or AT eecs o crcular and lnear polarzaon waves have een proposed [34 43], some o whch have enrched unconaly, such as hgh cross-polarzaon converson (CPC) ecency, muland and roadand operaon requency. However, mos o hese CMMs or AT eec do no have a road andwdh and hgh CPC smulaneously, whch resrcs her applcaons n many elds. More recenly, r-layer srucures ased on Fary-Pero-le resonance were proposed y Lu e al. [42], and he operaon andwdh could e exended o some degree [44 47]. However, up o now, he compose CMM wh ulraroadand as well as near uny CPC ecency (he relave andwdh o over 90% CPC ecency s greaer han 90%) has no een acheved. In addon, he hcness o hese compose CMM srucure samples s usually large, and he CPC ecency s relavely low, whch s nconvenen n some praccal applcaons, especally n rado and even mcrowave requency range. To ours es nowledge, nearly all o he proposed MM srucures wh he AT eec and CPC usually operae n a low magnude or a relave narrow requency range [14 20, 29 46]. Thus, he hgh magnude and roadand n MMs or cross-polarzaon converson and AT eec are sll desrale. In hs wor, ulra-roadand dode-le AT eec or lnear polarzaon waves and hgh-ecen CPC n a r-layer CCMM are proposed and demonsraed numercally and expermenally. The smulaon resuls show he CPC and dode-le AT eec or lnearly polarzed waves n an ulra-roadand requency range o GHz, where polarzaon converson rao (PCR) s greaer han 95%, whch agrees well wh expermen. The correspondng relave andwdh o our desgn can e exended exremely and up o %, whch s remarale compared wh he prevous CMM srucures [29 43]. 2. UNIT-CLL STRUCTUR DSIGN, SIMULATION AND XPRIMNT Fgure 1 shows he desgn schemacs o he CCMM, whch consss o a ds-spl-rng srucure (DSRs) sandwched wh wo wsed su-wavelengh meal grang srucure. As shown n Fg. 1(d), we decompose he un-cell srucure o he CCMM no hree unconal componens: layer A, layer B and layer C, and layers AB and BC are separaed y a delecrc spacer layer. Layer A and layer C can e unconed as a polarzaon selecor, and he specal polarzed (e.g., x-polarzed) wave can e allowed o pass hrough, u he oher polarzed (e.g., y-polarzed) wave wll e loced sgncanly [42, 46, 47]. Layer B can e served as a polarzaon converor. The DSRs o layer B have een proposed and nvesgaed [49, 50], whch ehave as a dpole resonaor and couple a specal elecrc eld componen o he ncden M wave, nally resulng n a paral polarzaon converson n a roadand range. Thus, gves us an dea usng he DSRs as he mddle layer resonaor srucure n desgn o he CCMM or roadand hgh-ecen CPC and AT eec. The ron (layer A) and ac (layer C) grang srucures are geomercally dencal u are wsed an angle o 90 n x-y plane o generae he srong chraly due o he near-eld elecrc and magnec cross-couplng eec. In hs desgn, he mddle spl drecon o he DSRs s roaed 45 along x(y) axs. Thus, an asymmery s nroduced n he un-cell srucure so ha has no lne o mrror symmery, enalng he AT eec only or lnear polarzaon wave. Smlar o prevous desgns [46, 47, 51], he mul-layered srucure o he proposed CCMM can orm a Fary-Pero-le cavy, whch could realze a mul-and or roadand AT eec due o he superposon o mulple relecons and ransmsson, and he mrror symmery reang along he propagaon drecon. The opmzed geomery parameers are as ollow: p x = p y = 9 mm, d =1.5mm, g 1 =0.9mm, r 1 =4.3mm, r 0 =1.3mm, w =1.2mm, g 2 =2.3mm, s =2.5mm, m =35µm. To sudy s ecency and gan nsgh no he physcal mechansm o he AT eec and CPC, he

3 Progress In lecromagnecs Research, Vol. 160, p x w g 2 p y d g 1 r 0 r 1 A (a) B () A B C y m C (c) z x s s (d) Fgure 1. The schemac dagram and poron phoograph o he esed sample o he desgned CCMM: (a), (), (c) are he schemes o he ron, mddle and oom layer srucure and he correspondng poron phoograph o he esed sample; (d) perspecve vew o he un-cell srucure. ne negraon echnque (FIT) smulaons are perormed y usng he requency doman solver o he CST Mcrowave Sudo. In smulaon, he perodc oundary condons were appled o he x and y drecons o he un-cell srucure whle he open oundary condons are se a z sdes. The meallc srucure layers were modeled as a copper lm wh an elecrc conducvy σ = S/m. We seleced low loss delecrc susrae Rogers RO4003 as he soropc spacer layer, and he relave permvy s ε r =2.75( ). To urher very s ecency expermenally, he desgned CCMM was arcaed no a un-cell sample y he convenonal prned crcu oard (PCB) process accordng o he opmzed geomerc parameers. In arcaon process, layer A and layer B meallc srucures were prned on oh sdes o he lan Rogers RO4003 oard, and layer C was prned on one sde o he lan Rogers RO4003 oard. Then, B plane and lan plane o C layer o he wo prned oards are glued closely ogeher usng an adhesve wh 3 mm hcness. Fnally, he oal dmenson o he arcaed CCMM sla s aou 198 mm 198 mm 5.1 mm. The measuremens o he arcaed CCMM sample were carred ou n an M anechoc chamer. The wo roadand horn anennas conneced o a vecor newor analyzer (Aglen PNA-X N5244A) y coaxal cale are used o measure he complex ransmsson coecens rom 3 o 17 GHz. In measuremen, he CCMM sla s placed n he mddle poson o he horn anennas, whch are dsrued y a dsance o 1.5 m o elmnae he near-eld eec [16, 18, 51]. The plane waves wh y- andx-polarzaons are generaed and receved y roang he orenaon o he wo horn anennas [52]. 3. TH RSULTS AND DISCUSSIONS We rsly sudy he responses o he sngle layer B -layer AB and -layer BC, respecvely. Fg. 2(a) shows he smulaed ransmsson coecens o he sngle layer B or he normal ncden waves propagaon along acward ( z) drecon. I can e seen ha he wo cross-polarzaon ransmsson coecens ( and ) are he same, and he magnudes are up o maxmal values o 0.51 and 4 a GHz and GHz, respecvely. A he meanme, he wo co-polarzaon ransmsson coecens ( xx and yy ) are also he same, and he magnudes are decreased o 0.33 and 0.53 a 9.25 GHz and GHz, respecvely. I means ha he sngle DSR can conver a lnearly polarzed wave parally o s orhogonal componen whn a roadand requency range. To ge nsgh no

4 92 Cheng e al. Transmsson specra xx (a) yy y, u, u v, 45 o y () v Transmsson specra (c) xx yy Transmsson specra (d) yy xx Fgure 2. Smulaed ransmsson coecens o he (a) layer B, (c) -layer AB and (d) -layer BC, () surace curren dsruons o he DSRs or he ncden y-polarzed wave along acward ( z) drecon a GHz. s mechansm o hs polarzaon converson ehavor, we smulaed he surace curren dsruon o he DSRs or he ncden y-polarzed waves along acward ( z) drecon a GHz, as shown n Fg. 2(). We can nd ha he low drecon o surace curren s roaed 45 along x(y) axs, whch orms elecrc dpolar resonances. As shown n he nse o Fg. 2(), he ncden y-polarzed wave can e decomposed no wo perpendcular componens, u and v, respecvely. A resonances, egenmodes are exced only y v componen o he elecrc eld or u componen o he ncden y- polarzed wave [49, 50]. For example, a GHz, only v componen o he elecrc eld s exced y he ncden y-polarzed wave. Thus, he ncden lnearly polarzed wave can only parally e convered o s orhogonal componen a resonances. In ac, he DSRs wll exce a dpolar oscllaon along he spl drecon wh wo orhogonal componens. One s along he x(y)-drecon, and he oher s along he y(x) drecon, nally resulng n a paral polarzaon converson n ransmsson. Fgures 2(c) and (d) gve he smulaed ransmsson coecens o he -layer AB and -layer BC, respecvely, where he cross-polarzaon ransmsson and has een enhanced sgncanly n conras o sngle layer B. As shown n Fg. 2(c), when he normal ncden wave pass hrough he layer AB along he acward ( z) drecon, xx and are nearly he same and close o zero across he whole requency range, whle s greaer han and yy elow n a roadand requency range. I ndcaes ha only y-polarzed wave can pass hrough he -layer AB and parally convered no x- polarzed wave n ransmsson, whle he x-polarzed wave s loced exremely due o he polarzaon selecon o layer A and he polarzaon converson o layer B [44, 46, 47]. As shown n Fg. 2(d), when he normal ncden wave pass hrough he -layer BC along he orward (+z) drecon,onl- polarzed wave can pass hrough and parally convered no y-polarzed wave n ransmsson, whle he y-polarzed wave s loced exremely. The -layer srucures (AB and BC) can orm a Fary-

5 Progress In lecromagnecs Research, Vol. 160, pero-le cavy, where he waves ravelng ac and orh eween hem can gve rh o nererence eec wh he mulple polarzaon couplngs, nally resulng n an enhanced CPC n a roadand requency range [49 51]. From Fgs. 2(c) and (d), can e conjecured ha he AT eec or lnearly polarzed waves can happen comnng layers A, B and C. I should e noced ha alhough he -layer srucures (AB and BC) can realze he CPC n a roadand range, he ecency s relavely low (he magnude o he cross-polarzaon ransmsson s elow 0.9). Accordng o he aove analyss, he CPC ecency and operaon andwdh could e enhanced sgncanly y addng a layer C o -layer AB ormng a r-layer ABC as shown n Fg. 1(d). To demonsrae he perormance o he r-layer srucure o he CCMM, we presen he smulaed and measured ransmsson coecens, respecvely, as shown n Fg. 3. The expermen resuls are n qualave agreemen wh he smulaons, excep or he slgh dscrepances n he ransmsson magnudes. These undesred devaons could e caused y he possle reasons ncludng he arcaon mperecon and ny dsoron o he CCMM sla, and he ne dmensons o he sample n he expermen u no he smulaon. Fgs. 3(a) and (c) show he smulaed and measured ransmsson specra or he normal ncden waves propagaon along acward ( z) drecon, respecvely. I can e seen ha he co-polarzaon ransmsson coecens xx o ncden x-polarzed wave and yy o ncden y-polarzed wave are exacly he same wh each oher, and oh o hem are less han 37 n he requency range o GHz. Neverheless, he cross-polarzaon ransmsson coecens Smulaon Smulaon xx xx Transmsson specra yy yy (a) () xpermen xx xpermen xx Transmsson specra yy yy (c) (d) Fgure 3. (a), () Smulaed and (c), (d) expermenal resuls: ransmsson coecens ( () xx, (), () and () yy ) or he normal ncden waves passng hrough he CCMM along (a), (c) acward ( z) drecon (), (d) orward (+z) drecon.

6 94 Cheng e al. o ncden y-polarzed wave and o ncden x-polarzed wave are deren remaraly. When he waves propagae along he acward ( z) drecon, s near zero across he whole requency range whle or he y-polarzed wave s greaer han 0.9 whn he requency range o GHz correspondng o a relave andwdh o aou %. In addon, he maxmal values o are up o 0.99 a 4.67 GHz, 7.24 GHz, and GHz, respecvely. Smlar o he Fary-Pero-le resonances, he near uny ransmsson o he cross-polarzed wave can e acheved owng o he nererence eec eween he mulple polarzaon couplngs o he waves ransmsson and relecon n he r-layer srucure [42 47, 49 51]. I ndcaes ha he proposed CCMM can only realze a hghecency CPC or he ncden y-polarzed waves propagaon along acward ( z) drecon. Fgs. 3() and (d) presen he ransmsson specra or he orward (+z) propagang waves. and o crosspolarzaon nerchange wh each oher, and xx, yy, xx and yy o co-polarzaon are conssen when he propagaon drecon s reversed. In conrary o he resuls n Fgs. 3(a) and (c), he proposed CCMM can only accomplsh a hgh-ecency CPC or he ncden x-polarzed waves (see Fgs. 3(), (d)). Compared wh he sngle layer B, -layer AB and BC srucures, he operaon andwdh and CPC ecency have een mproved sgncanly hrough hs r-layer srucure o he proposed CCMM. Thus, can e expeced ha he proposed CCMM sla can e used as a ransparen ulra-roadand cross-polarzaon converor. Ths dsnc hgh-ecen CPC or he reversed propagaon drecons va remarale AT eec s manly arued o he specal srucure chraly o he CCMM [51 53]. These resuls mply ha he proposed CCMM can acheve gan AT eec or normal ncden lnearly polarzed waves. To clearly characerze he AT eec, he AT coecens (Δ ln ) or smulaon and measuremen were calculaed as shown n Fg. 4, and he calculaon equaons are dealed n [15, 16]. To guaranee he gan AT eec o he normal ncden lnearly polarzed waves or he proposed CCMM, he crosspolarzaon ransmsson coecens ( () and () ) propagaon along he oppose drecon are also deren whch should e sased as [15, 16]: Δ x,() ln = () 2 () 2 = Δ y,() ln 0. Isoserved clearly ha wo curves o Δ x ln and Δy ln are exacly he oppose, and her asolue values are equal and greaer han n an ulraroadand range rom 4.36 o GHz. In addon, he magnudes o he AT coecens are greaer han 0.95 a resonance requences. The measuremens agree well wh he smulaons n prncple. I should e noced ha he AT coecens or crcular polarzaon are ep o zero (no shown). Thus, he proposed CCMM only exhs sgncan AT eec or he lnearly polarzed waves, u no or he crcular polarzaons. I s also noeworhy ha he AT eec wh smulaneous hgh amplude and ulraroadand has een realzed expermenally usng he r-layer srucure CCMM, whch s very comparale wh prevous repored CMMs [29 38, 42 48]. To urher characerze he AT eec, we calculaed he oal ransmance (T y ) o ransmed Asymmerc ransmsson/δ Δ Δ y ln x ln (a) Δ Δ y ln x ln () Fgure 4. The (a) smulaed and () expermenal AT coecens (Δ ln ).

7 Progress In lecromagnecs Research, Vol. 160, x-polarzed waves or oh x-polarzed and y-polarzed ncden waves along he orward (+z) and acward (z) drecons. The oal ransmance o wave propagaon along he orward and acward = () xx 2 + () 2 and 2, respecvely. Fgs. 5(a), () presen he calculaed oal ransmance (T x )o drecons or x polarzaon and y polarzaon can e dened as [47]: Tx () = () 2 + () Ty () yy smulaon and measuremen, respecvely. I s ovous ha he oal ransmance (T x )ohewaves propagaon along he acward ( z) drecon s exremely deren rom ha along he orward (+z) drecon. In oh smulaon and expermen, he oal ransmance (T x )ohex-polarzed wave s greaer han or he acward ( z) drecon n an ulraroadand range rom 4.36 o GHz, whle s near zero or he orward (+z) drecon. Thereore, s urher conrmed ha he CCMM can realze AT eec, whch s smlar o a dode-le eec n an ulraroadand range. Furhermore, we calculaed he PCR o x-polarzed wave propagaon along he orward (+z) drecon and y-polarzed wave propagaon along he acward ( z) drecon, respecvely, and he calculaon equaons are dealed n [47]. Fgs. 6(a), () dsplay he calculaed PCRs or smulaon x Toal ransmance/t Smulaon +z -z xpermen +z -z (a) () Fgure 5. (a) The smulaed and () expermenal oal ransmance (T y ) o ransmed x-polarzed waves or oh he x-polarzed and y-polarzed ncden waves propagaon along orward (+z) and acward ( z) drecon. Sm. Sm. PCR x xp. PCR y xp. 2 2 (a) Fgure 6. The smulaed and measured resuls: PCR or (a) he x-polarzed wave propagaon along he orward (+z) drecon, and () he y-polarzed wave propagaon along he acward ( z) drecon. ()

8 96 Cheng e al. and measuremen, respecvely. I can e seen ha he PCR o x-polarzed wave propagaon along he orward (+z) andy-polarzed wave propagaon along he acward ( z) drecon are conssen, and oh o hem always eep hgh magnude o aou 0.99 n an ulraroadand requency range. I should e noced ha he PCRs o y-polarzed wave along +z drecon and x-polarzed wave along z drecon are also conssen, u oh o hem wll always e ep near zero across he whole requency range (no shown). Thus, our desgned CCMM sla has a nearly perec CPC capaly n an ulraroadand requency range. The converson eween x-polarzed and y-polarzed waves plays an mporan role n enhancng he hgh CPC eec. Thereore, o gan eer nsgh no he lnear polarzaon roaon or converson o he proposed CCMM sla, he polarzaon azmuh angle (θ) and ellpcy (η) oray-polarzed wave along he acward ( z) drecon were calculaed, respecvely, and he calculaon equaons are dealed n [52]. Fg. 7 gves he smulaed polarzaon azmuh angle and ellpcy. I can e seen ha he value o θ s close o 90 n requency ranges o GHz and GHz, and close o 90 n requency range o GHz, mplyng ha he ncden y-polarzed wave s mosly ransmed o he x-polarzed wave wh deren roaon drecons ( x and +x drecons). I means ha wh respec o he ncden wave propagaon along he acward ( z) drecon, he polarzaon plane o he ransmed wave has a near 90 roaon n requency ranges o GHz and GHz, and +90 roaon n requency range o GHz. I should e noced ha he θ o x-polarzed wave along he acward ( z) drecon wll e close o zero (no shown). Therey, can e appled o realze he approxmae ulraroadand 90 polarzaon roaor or he ncden specal polarzaon wave. In addon, he asolue value o η s elow 3 n he enre requency range, ndcang ha he ransmed waves have a relavely hgh pury o lnear polarzaon. These resuls urher llusrae ha he CCMM can conver a lnearly polarzed wave o s cross-polarzaon whn an ulraroadand requency range. θ (degree) θ η η (degree) Fgure 7. The smulaed polarzaon azmuh roaon angle (θ) and polarzaon ellpcy angle (η) or he normal ncden y-polarzed wave propagaon along he acward ( z) drecon. In order o urher llusrae he hgh-ecency cross-polarzaon converson and dode-le AT eec o he proposed CCMM, we also smulaed and analyzed he elecrc elds dsruons a deren resonance requences. The AT eec and CPC eec can e vsualzed y elecrcal eld dsruons clearly. Fg. 8 presen he vsualzed evoluon process o elecrc elds n he x-z plane o he mddle o un-cell srucure ncludng ncomng regme, susrae and he ougong regme a 1 =4.67 GHz, 2 =7.24 GHz, and 3 =11.57 GHz, respecvely. As shown n Fgs. 8(a1), (a3) and (c1), (c3), a 4.67 GHz and GHz, he ncden y-polarzed (+y drecon) and x-polarzed (+x drecon) waves propagaon along acward ( z)andorward(+z) drecons rom he ron and ac meallc srucures exce he guded resonan modes o he uncell srucure and are nally perecly convered o he ransmed x-polarzed ( x drecon) and y- polarzed ( y drecon) waves, respecvely. A 7.24 GHz, as shown n Fgs. 8(a2) and (c2), he ncden

9 Progress In lecromagnecs Research, Vol. 160, (a1) = 4.67 GHz = 7.24 GHz = GHz (a2) (a3) (1) (2) (3) (c1) (c2) (c3) (d1) (d2) (d3) Fgure 8. Smulaed elecrc eld dsruons o he CCMM un-cell srucure n he x-z plane n case o he ncden (a1) (a3) y-polarzed and (1) (3) x-polarzed wave along acward ( z) drecon, and (c1) (c3) x-polarzed and (d1) (d3) y-polarzed wave along orward (+z) drecon a deren resonance requences: (a1) (d1) 1 =4.67 GHz, (a2) (d2) 2 =7.24 GHz, (a3) (d3) 3 =11.57 GHz. y-polarzed (+y drecon) and x-polarzed (+x drecon) waves propagaon along acward ( z) and orward (+z) drecon are nally perecly convered o he ransmed x-polarzed (+x drecon) and y-polarzed (+y drecon) waves, respecvely. As shown n Fgs. 8(1) (3) and (d1) (d3), he ncden x-polarzed (+x drecon) waves and y-polarzed (+y drecon) waves propagaon along acward ( z) and orward (+z) drecon are suppressed exremely a he enrances a aove resonance requences, resulng n a very low ransmsson whou polarzaon converson. These resuls urher mply ha when he waves are propagang along he acward ( z) drecon, only he y-polarzed waves can e seleced o pass hrough he CCMM sla and nally convered o he ransmed x-polarzed waves whle he x-polarzed waves canno allow o e ransmed. When propagaon drecon o he ncden

10 98 Cheng e al. wave s reversed, only he x-polarzed waves can e seleced and convered o he y-polarzed waves, and he y-polarzed waves canno. In eec, all he elds paerns wll e wsed nsde he un-cell srucure as a consequence o nerlayer nererence couplng eec a hese resonance requences [42 47, 49 51]. These elecrc eld dsruons pcures o un-cell srucure are n excellen conssency wh he resuls n Fgs The eld dsruons explcly ndcae ha he excaon o local resonan modes and nerlayer couplng n he r-layer ABC srucure are crucal o he ulraroadand AT eec and CPC unconaly, whch s smlar o he prevous desgned srucures [42 47, 49 51]. These eaures o elecrc eld dsruons o un-cell srucure also urher conrm ha he CCMM could e served as an ulraroadand 90 polarzaon roaor or cross-polarzaon converor. 4. CONCLUSION In concluson, we propose a CCMM wh he DSRs sandwched eween wo layers o wsed suwavelengh meal grang, whch can realze an ulraroadand AT eec and hgh-ecen CPC n mcrowave regon. Boh smulaon and expermen reveal ha he cross-polarzaon ransmsson coecens ( and ) over 0.9 o he proposed CCMM can e realzed rom GHz, correspondng o a relave andwdh o aou %, whch are much larger han prevous CMMs [29 38, 42 48]. Meanwhle, also exhs CPC wh nearly 99% ecency and approxmaely ±90 polarzaon roaon a aove requency range. Thus, our desgn can e unconed as an ulraroadand lnear polarzaon converor or roaor. The whole hcness our desgn s aou 5.1 mm, whch s hnner han he prevous proposed CMMs converor or roaor [42 44]. The enhanced AT eec and hgh-ecen CPC o he proposed CCMM can e arued o he Fary-Péro-le nererence eec o cross couplng or he elecrc and magnec elds [49 51]. In addon, owng o he geomery scalaly, he proposed srucure could operae well a eraherz and even opcal regon y scalng down he geomerc dmensons. Wh he remarale properes o ulraroadand and hgh-ecency, we eleve ha our proposed CCMM wll e enecal or desgnng crculaor, solaor and polarzaon converor or roaor. ACKNOWLDGMNT Ths wor s suppored y he Naonal Naural Scence Foundaon o Chna (Gran Nos. U and ), he Youh scence and echnology acone culvaon plan projec o he Wuhan Unversy o Scence and Technology (Gran No. 2016xz010), and he Naural Scence Foundaon o Hue Chna (Gran No. 2017CFB588). RFRNCS 1. Lndell, V., A. Shvola, S. Treyaov, e al., lecromagnec Waves n Chral and B-soropc Meda, Arech House, London, Pendry, J. B., A chral roue o negave reracon, Scence, Vol. 306, , Plum,., J. Zhou, J. Dong, V. A. Fedoov, T. Koschny, C. M. Sououls, and N. I. Zheludev, Meamaeral wh negave ndex due o chraly, Phys. Rev. B, Vol. 79, No. 3, , Monzon, C. and D. W. Foreser, Negave reracon and ocusng o crcularly polarze waves n opcally acve meda, Phys. Rev. Le., Vol. 95, , L, J., F.-Q. Yang, and J.-F. Dong, Desgn and smulaon o L-shaped chral negave reracve ndex srucure, Progress In lecromagnecs Research, Vol. 116, , L, Z., K. B. Alc,. Cola, and. Ozay, Complemenary chral meamaerals wh gan opcal acvy and negave reracve ndex, Appl. Phys. Le., Vol. 98, , Cheng, Y., Y. Ne, and R. Z. Gong, Gan opcal acvy and negave reracve ndex usng complemenary U-shaped srucure assemly, Progress In lecromagnecs Research M, Vol. 25, , 2012.

11 Progress In lecromagnecs Research, Vol. 160, Cheng, Y., Y. Ne, L. Wu, and R. Z. Gong, Gan crcular dchrosm and negave reracve ndex o chral meamaeral ased on spl-rng resonaors, Progress In lecromagnecs Research, Vol. 138, , Decer, M., R. Zhao, C. M. Sououls, S. Lnden, and M. Wegener, Twsed spl-rng-resonaor phoonc meamaeral wh huge opcal acvy, Op. Le., Vol. 35, No. 10, , Kwon, D. H., P. L. Werner, and D. H. Werner, Opcal planar chral meamaeral desgns or srong crcular dchrosm and polarzaon roaon, Op. xpress, Vol. 16, No. 16, , Fedoov, V. A., P. L. Mladyonov, S. L. Prosvrnn, A. V. Rogacheva, Y. Chen, and N. I. Zheludev, Asymmerc propagaon o elecromagnec waves hrough a planar chral srucure, Phys. Rev. Le., Vol. 97, No. 16, , Fedoov, V. A., A. S. Schwanece, N. I. Zheludev, V. V. Khardov, and S. L. Prosvrnn, Asymmerc ransmsson o lgh and enanomercally sensve plasmon resonance n planar chral nanosrucures, Nano Le., Vol. 7, No. 7, , Sngh, R.,. Plum, C. Menzel, C. Rocsuhl, A. K. Azad, R. A. Chevlle, F. Lederer, W. Zhang, and N. I. Zheludev, Teraherz meamaeral wh asymmerc ransmsson, Phys. Rev. B, Vol. 80, No. 15, (5), Menzel, C., C. Rocsuhl, and F. Lederer, Advanced Jones calculus or he classcaon o perodc meamaerals, Phys. Rev. A, Vol. 82, , Huang, C., Y. Feng, J. Zhao, Z. Wang, and T. Jang, Asymmerc elecromagnec wave ransmsson o lnear polarzaon va polarzaon converson hrough chral meamaeral srucures, Phys. Rev. B, Vol. 85, No. 19, , Cheng, Y., Y. Ne, X. Wang, and R. Gong, An ulrahn ransparen meamaeral polarzaon ransormer ased on a ws-spl-rng resonaor, Appl. Phys. A, Vol. 111, , Cong, L., W. Cao, X. Zhang, Z. Tan, J. Gu, R. Sngh, J. Han, and W. Zhang, A perec meamaeral polarzaon roaor, Appl. Phys. Le., Vol. 103, No. 17, , Cheng, Y. Z., Y. Ne, Z. Z. Cheng, L. Wu, X. Wang, and R. Z. Gong, Broadand ransparen meamaeral lnear polarzaon ransormer ased on rple-spl-rng resonaors, Journal o lecromagnec Waves and Applcaons, Vol. 27, , We, Z., Y. Cao, Y. Fan, X. Yu, and H. L, Broadand polarzaon ransormaon va enhanced asymmerc ransmsson hrough arrays o wsed complemenary spl-rng resonaors, Appl. Phys. Le., Vol. 99, No. 22, , Han, J., H. L, Y. Fan, Z. We, C. Wu, Y. Cao, X. Yu, F. L, and Z. Wang, An ulrahn wssrucure polarzaon ransormer ased on sh-scale meallc wres, Appl. Phys. Le., Vol. 98, No. 15, , Ma, X., C. Huang, M. Pu, C. Hu, Q. Feng, and X. Luo, Mul-and crcular polarzer usng planar spral meamaeral srucure, Op. xpress, Vol. 20, No. 14, , Song, K., X. Zhao, Y. Lu, Q. Fu, and C. Luo, A requency-unale 90-polarzaon roaon devce usng compose chral meamaerals, Appl. Phys. Le., Vol. 103, , Xu, H.-X., G.-M. Wang, M.-Q. Q, and T. Ca, Dual-and crcular polarzer and asymmerc specrum ler usng ulrahn compac chral meamaeral, Progress In lecromagnecs Research, Vol. 143, , Wu, L., Z. Yang, Y. Cheng, R. Gong, M. Zhao, Y. Zheng, J. Duan, and X. Yuan, Crcular polarzaon converers ased on -layered asymmercal spl rng meamaerals, Appl. Phys. A, Vol. 116, No. 2, , Yogesh, N. F., T. Lan, and F. Ouyang, Far-nrared crcular polarzaon and polarzaon lerng ased on Ferma s spral chral meamaeral, I Phooncs Journal, Vol. 7, No. 3, 1 12, Ma, X., Z. Xao, and D. Lu, Dual-and cross polarzaon converer n layered complemenary chral meamaeral, Journal o Modern Opcs, Vol. 63, No. 10, , Tang, J., Z. Xao, K. Xu, X. Ma, D. Lu, and Z. Wang, Cross polarzaon converson ased on a new chral spral slo srucure n THz regon, Op. Quan. lecron., Vol. 48, 111, 2016.

12 100 Cheng e al. 28. Xu, K.-K., Z.-Y. Xao, J.-Y. Tang, D.-J. Lu, and Z.-H. Wang, Ulra-road and and dual-and hghly ecen polarzaon converson ased on he hree-layered chral srucure, Physca, Vol. 81, , Menzel, C., C. Helger, C. Rocsuhl,.-B. Kley, A. Tunnermann, T. Persch, and F. Lederer, Asymmerc ransmsson o lnearly polarzed lgh a opcal meamaerals, Phys. Rev. Le., Vol. 104, , Kang, M., J. Chen, H. Cu, Y. L, and H. Wang, Asymmerc ransmsson or lnearly polarzed elecromagnec radaon, Op. xpress, Vol. 19, 8347, Mulu, M., A.. Aosman, A.. Sereryannov, and. Ozay, Asymmerc ransmsson o lnearly polarzed waves and polarzaon angle dependen wave roaon usng a chral meamaeral, Op. xpress, Vol. 19, , Novsy, A. V., V. M. Galynsy, e al., Asymmerc ransmsson n planar chral spl-rng meamaerals: Mcroscopc Lorenz-heory approach, Phys. Rev. B, Vol. 86, No. 7, , Mulu, M., A.. Aosman, A.. Sereryannov, and. Ozay, Dodele asymmerc ransmsson o lnearly polarzed waves usng magneoelecrc couplng and elecromagnec wave unnelng, Phys. Rev. Le., Vol. 108, , Sh, J. H., X. C. Lu, S. W. Yu, T. T. Lv, Z. Zhu, H. F. Ma, and T. J. Cu, Dual-and asymmerc ransmsson o lnear polarzaon n layered chral meamaeral, Appl. Phys. Le., Vol. 102, , Xu, Y., Q. Sh, Z. Zhu, and J. Sh, Muual converson and asymmerc ransmsson o lnearly polarzed lgh n layered chral meamaeral, Op. xpress, Vol. 22, No. 21, , Han, S., H. Yang, L. Guo, X. Huang, and B. Xao, Manpulang lnearly polarzed elecromagnec waves usng he asymmerc ransmsson eec o planar chral meamaerals, J. Op., Vol. 16, No. 3, , Zhou, Z. and H. Yang, Trple-and asymmerc ransmsson o lnear polarzaon wh deormed S-shape layer chral meamaeral, Appl. Phys. A, Vol. 119, No. 1, , Wang, Y. H., J. Shao, J. L, Z. Lu, J. L, Z. G. Dong, and Y. Zha, Broadand hgh-ecency ransmsson asymmery y a chral layer ar measrucure, J. Appl. Phys., Vol. 117, No. 17, , Lu, D., Z. Xao, X. Ma, and Z. Wang, Asymmerc ransmsson o lnearly and crcularly polarzed waves n meamaeral due o symmery-reang, Appl. Phys. xpress, Vol. 8, No. 5, , Wang, C., D. F. Tang, J. F. Dong, M. H. L, and W. K. Pan, Broad dual-and asymmerc ransmsson o crcular polarzed waves n near-nrared communcaon and, Op. xpress, Vol. 25, No. 10, , J, R., S. W. Wang, X. Lu, and W. Lu, Gan and roadand crcular asymmerc ransmsson ased on wo cascadng polarzaon converson caves, Nanoscale, Vol. 8, No. 15, , Lu, D. Y., M. H. L, X. M. Zha, L. F. Yao, and J. F. Dong, nhanced asymmerc ransmsson due o ary-pero-le cavy, Op. xpress, Vol. 22, , Xao, Z.-Y., D.-J. Lu, X.-L. Ma, and Z.-H. Wang, Mul-and ransmssons o chral meamaerals ased on Fary-Pero le resonaors, Op. xpress, Vol. 23, No. 6, , Lu, Y., S. Xa, H. Sh, A. Zhang, and Z. Xu, cen dual-and asymmerc ransmsson o lnearly polarzed wave usng a chral meamaeral, Progress In lecromagnecs Research C, Vol. 73, 55 64, Shang, X.-J., X. Zha, L.-L. Wang, M.-D. He, Q. L, X. Luo, and H.-G. Duan, Asymmerc ransmsson and polarzaon converson o lnearly polarzed waves wh layer L-shaped measuraces, Appl. Phys. xpress, Vol. 10, , Wang, H.-B., X. Zhou, D.-F. Tang, and J.-F. Dong, Dode-le roadand asymmerc ransmsson o lnearly polarzed waves ased on Fary-Pero-le resonaors, Journal o Modern Opcs, Vol. 7, 1 10, 2017.

13 Progress In lecromagnecs Research, Vol. 160, Cheng, Y., R. Gong, and L. Wu, Ulra-roadand lnear polarzaon converson va dode-le asymmerc ransmsson wh compose meamaeral or eraherz waves, Plasmoncs, Vol. 12, , Huang, X., B. Xao, D. Yang, and H. Yang, Ulra-roadand 90 polarzaon roaor ased on -ansoropc meamaeral, Opcs Communcaons, Vol. 338, , Mar. 1, Cheng, Y., W. Whayachumnanul, A. Upadhyay, H. Danel, Y. Ne, R. Gong, M. Bhasaran, S. Srram, and D. Ao, Ulra-roadand relecve polarzaon converor or eraherz waves, Appl. Phys. Le., Vol. 105, No. 19, , Zhao, J. and Y. Cheng, A hgh-ecency and roadand relecve 90 lnear polarzaon roaor ased on ansoropc meamaeral, Appl. Phys. B, Vol. 122, No. 10, 255, Grady,N.K.,J..Heyes,D.R.Chowdhury,Y.Zeng,M.T.Reen,A.K.Azad,A.J.Taylor, D. A. Dalv, and H. T. Chen, Teraherz meamaerals or lnear polarzaon converson and anomalous reracon, Scence, Vol. 340, No. 6138, , Cheng, Y., C. Wu, Z. Z. Cheng, and R. Z. Gong, Ulra-compac mul-and chral meamaeral crcular polarzer ased on rple wsed spl-rng resonaor, Progress In lecromagnecs Research, Vol. 155, , Song, K., Y. Lu, C. Luo, and X. Zhao, Hgh-ecency roadand and muland crosspolarzaon converson usng chral meamaeral, J. Phys. D: Appl. Phys., Vol. 47, , 2014.