不同形状单贴片单层微带贴片天线的扩展带宽技术_英文_

1、2004年4月第27卷第2期北京邮电大学学报Jou rnal of Beijing U n iversity of Po sts and T elecomm un icati on s A p r .2004V o l .27N o.2文章编号:100725321(2004022*Bandw idth Enhancem en t Techn iques forD ifferen t Shapes of Si ngle -Pa tchSi ngle -Layer M icrostr ip Pa tch An tennaABDALLA H A .S .,M O HAMM ED Y .E .,L I

2、 U Y .A .(T elecomm unicati on Engineering Schoo l ,Beijing U niversity of Po sts and T elecomm unicati ons ,Beijing 100876,Ch ina Abstract :Several techn iques of bandw idth enhancem en t are adop ted in th is p ap er fo r differen t shap es of single 2layer single 2p atch an tenna .T hey are m ain

3、 ly :thep robe 2fed square p atch an tenna w ith sho rting p in s ,and the p robe 2fed rectangu lar p atch an tenna w ith a p air of w ide slits (E 2shap ed p atch .T he analyses w ere carried ou t u sing m ethod of m om en ts softw are p ackage .It is show n that the p robe 2fed square p atch an te

4、nna can be m ade resonate at th ree differen t frequencies of 1183GH z ,2116GH z and 2174GH z resp ectively w ith a p eak gain of 914dB .T he E 2shap ed p atch is designed to resonate at tw o differen t frequencies of 2113GH z and215GH z w ith overall i m p edance bandw idth of abou t 33133%(retu rn

5、 lo ss -10dB w ith resp ect to a cen ter frequency of 214GH z.T he p eak gain is abou t 9125dB .Key words :m icro stri p p atch an tenna ;bandw idth enhancem en t ;b road 2band an ten 2naCLC nu m ber :TN 82011D ocu m en t code :A不同形状单贴片单层微带贴片天线的扩展带宽技术阿朴杜拉A .S .,穆罕默德Y .E .,刘元安(北京邮电大学电信工程学院,北京100876摘要

6、:采用多种带宽改进技术,应用于不同形状的单层片状天线,主要包括:短路销钉,双宽缝(E形等同时,采用基于M OM 的软件包分析了天线性能,证明方形天线可以工作在3个频率点,即1183GH z 、2116GH z 和2174GH z ,其最大的增益达到914dB ;E 形天线工作在2113GH z 和215GH z ,当中心频率为214GH z 时,带宽达到33133%(反射损耗-10dB ,其最大增益为9125dB 关键词:微带天线;带宽改进;广带天线收稿日期:2002207210作者简介:A bdallah A .S .(1958-,Iraqi ,男,博士生E 2m ail :kareem _

7、rn ho tm M icro stri p p atch an tennas have a num ber of u sefu l p rop erties such as ligh t w eigh t ,con 2fo rm ab ility ,low co sts ,and the fact that they are si m p le to m anufactu re .How ever ,one of theseri ou s li m itati on s of these an tennas has been their narrow bandw idth c

8、haracteristics.T he i m p edance bandw idth of a typ ical m icro stri p p atch an tenna is less than1%to several p er2 cen ts fo r th in sub strates satisfying the criteria h o<01023fo rr10to h o<0107fo rr2131.T h is is in con trast to15%to50%bandw idth of comm on ly u sed an tenna elem en ts

9、such as di po le,slo ts,and w avegu ide ho rn s.It is concluded from R ef.1that the increase in (hand decrease in(rcan be u sed to increase the i m p edance bandw idth of the m icro stri p p atch an tenna.How ever,th is app roach is u sefu l up to h o<0102on ly.T he disadvan tage of u sing th ick

10、 and h igh dielectric con stan t sub strates are m any including the poo r radiati on effi2 ciency due to su rface w ave generati on,the sp u ri ou s radiati on from m icro stri op step2in2w idth and o ther discon tinu ities,the generati on of h igher o rder m odes along the th ickness.W ith the rap

11、 id developm en t of w ireless comm un icati on s,single p atch single2layer w ide band an tennas have attracted m any atten ti on s224.In th is p ap er,differen t tech2 n iques are u sed in o rder to increase the bandw idth o r in troducing m u lti2band op erati on of m i2 cro stri p p atch an tenn

12、a.T he analyses w ere based on m ethod of m om en ts w ith the aid of the electrom agnetic softw are“En sem b le SV”.In Secti on22,a p robe2fed single2layer single p atch m icro stri p an tenna w ith one edge sho rted by th ree symm etrical sho rting p in s is p resen ted. T he b roadband featu re o

13、f th is an tenna is m ain ly realized by exciting th ree resonan t m odes in a single p atch and m ak ing them sufficien tly clo se to one ano ther.In Secti on23,a p robe2fed single2layer single2p atch w ith a p air of w ide slits is in troduced,designed and analyzed to ach ieve b roadband op erati

14、on.Conclu si on is p resen ted in Secti on24.1Probe-fed Si ngle-Layer Si ngle-Pa tch An tennaIt is w ell know n that a si m p le rectangu lar p atch can be regarded as a cavity w ith m ag2 netic w alls on its radiating edges5.Tw o o rthogonal resonan t m odes can be excited u sing one si m p le p ro

15、be feed that is su itab ly attached to the p atch6.A lternatively,tw o discrete reso2 nan t m odes can also be excited if the p robe feed is disp laced p rop erly from bo th p rinci p al axes of the rectangu lar p atch and one edge of the rectangu lar is sho rted by the u se of several sho rting p i

16、n s.F ig.1dep icts the configu rati on of the p ropo sed b roadband p atch an tenna that is com po sed of square p atch,th ree sho rting p in s,one p robe feed and air2filled sub strate.T he self2inductance of sho rting p in o r the p robe feed becom es m o re critical as the frequency of in2 terest

17、 increases.It can be determ ined from the fo llow ing equati on7L si=010046l lg4ld-0175(1w here,L si2the self2inductance in(H;l2the length of sho rting p in o r p robe2feed in(c m; d2the diam eter of sho rting p in o r p robe2feed in(c m.How ever,a square m icro stri p p atch w ith its ground p lane

18、 sep arated by an air2filled sub2 strate exh ib its cap acitive behavi ou r to som e ex ten t,as there is a po ten tial difference betw een bo th conducto rs.T he cap acitance can be si m p ly calcu lated byC=0r Ah(255第2期ABDAL I A H A S et al.Bandw idth Enhancem en t T echn iques fo r D ifferen t Sh

19、apes ofF ig .1Single 2patch single 2layer patch an tenna w ith th ree sho rting p in s W here ,(o is the free 2sp ace p erm ittivity ;(r is the relative dielectric con stan t of thesub strate ;(A is the p atch area ;and (h isthe sub strate th ickness.T he equ ivalen t circu it of th is an tenna issh

20、ow n in F ig .2,w here (L 1,(L 2,and (L 3rep resen t the inductances of the sho rting p in s ,and (L P rep resen ts the inductance of thep robe feed .(C rep resen ts the cap acitance be 2tw een the p atch and the ground p lane .It isw o rth m en ti on ing that the resistances of thep robe feed ,the

21、sho rting p in s ,and the squarep atch can be neglected since their resistancesare very s m all com p ared w ith their reactancesat the frequency of in terest 7.T he p atch is cho sen to be a square oneF ig .2Equ ivalen t C ircu it of Single 2patch Single layer an tenna w ith th ree sho rting p in s

22、w ith length (L equals to R ef .5:L =12f 0e 00-2L (3W here ,(f o is the p atch resonan t frequency ;(o is the free 2sp ace p erm eab ility ;(e is theeffective dielectric con stan t given bye =r +12+r -121+12h L-1 2(4and (L is the line ex ten si on of the p atchgiven byL =01412h (e +013(L h +01264(e

23、-01258(L h +018(5T he disp lacem en t of p robe feed from the tw o p rinci p al axes of the square p atch help in exciting TM m n m ode as R ef .8:f m n =c 2r m L 2+n W 2(6W here ,(c is the velocity of ligh t ;(L is the effective p atch length given by Eqn .(3;and (W is the effective p atch w idth g

24、iven by R ef .9:W =2h lnhF W +1+(2h W 2(7W here ,(F is given by :F =6+(2-6exp (-42 3(h W 3 4(8W here ,(W rep resen ts the p atch w idth that is equal to the p atch length .To realize the exci 265北京邮电大学学报第27卷tati on of h igher resonan t m ode ,it is necessary to op ti m ize the po siti on of the p ro

25、be feed .T he design si m u lati on show s that the distance betw een the sho rted edge and the p robe feed shou ld be sufficien tly w ide to reduce the influence of the inp u t i m p edance cau sed by the ex is 2tence of the sho rting p in s w h ile the p robe feed po in t shou ld be disp laced fro

26、m the tw o p rinci 2p al axes of the square p atch to excite ex tra resonan t m odes.T he radiu s of the p robe shou ld be larger than that of the sho rting p in s to satisfacto rily m atch the inp u t i m p edance of the an 2tenna .T he design p aram eters of th is an tenna are as fo llow s :L =80m

27、m ,h =8mm ,sho rting p in radiu s =011mm ,locati on of the p robe 2feed w ith resp ect to the tw o p rinci p al axes =(72,17168mm ,and the locati on s of the th ree sho rting p in s w ith resp ect to the tw o p rinci p al ax 2es =(011,-38,(011,0,and (011,38mm resp ectively .F ig .3show s its retu rn

28、 lo ss again st frequency ,from w h ich it is clear that there are th ree resonan t frequencies f o 1=1183GH z ,f o 2=2116GH z ,f o 3=2174GH z w ith retu rn lo ss values of -16,-1413and -27123dB resp ec 2tively .F ig .4show s the inp u t gain again st frequency sp ectrum of in terest .T he p eak gai

29、n is 914dB at the first tw o resonan t frequencies .How ever ,it is on ly 012dB at the th ird resonan t frequency ,from w h ich it is concluded that at th is frequency the an tenna acts as an om n idirec 2ti onal one .T he E 2p lane and H 2p lane radiati on p attern s at the above th ree resonan t f

30、requen 2cies are show n in F ig .5.T he p eak cro ss po larizati on radiati on s are relatively h igh due to u s 2ing th ick sub strate th ickness and long p robe p in in the sub strate layer .How ever ,it is still app licab le fo r som e comm un icati on app licati on s such as m ob ile hand p hone

31、 an tennas ,since m o st electric fields w ill m o re o r less diffract off the fin ite ground 2p lane edges of the term i 2nals 10 .F ig .3R etu rn lo ss fo r the p robe 2fed single 2layersingle 2patch an tenna F ig .4Gain of p robe 2fed single layer single 2patch an tenna2Probe -Fed Si ngle -Pa tc

32、h W ith A Pa ir of W ide Sl itsR ecen tly ,it has show n that ,by em bedding a U 2shap ed slo t in the rectangu lar p atch ,an i m p edance bandw idth greater than 20%can be easily ach ieved fo r a m icro stri p an tenna w ith a p robe feed 11212.In th is p ap er ,a novel single p atch w ide 2band m

33、 icro stri p rectangu lar p atchan tenna w ith a p air of w ide slits is adop ted .T he topo logical shap e of the p atch resem b les the letter “E ”,hence som eti m es called E 2shap ed p atch an tenna 13.T he tw o w ide slits as show n75第2期ABDAL I A H A S et al .Bandw idth Enhancem en t T echn iqu

34、es fo r D ifferen t Shapes of F ig .5H 2p lane and E 2p lane radiati on pattern s fo r a p rob 2fed single layer single 2patch an tenna in F ig .6are in serted at one of theradiating edges of the rectangu larp atch .T he rectangu lar p atch itself hasdi m en si on s of (L ×W .A ir sub strateof

35、th ickness (h sep arates the p atchfrom the ground p lane .T he tw o w ideslits are of the sam e length (l andw idth (W 1.T he sep arati on of thetw o slits is (W 2and they are p lacedsymm etrically w ith resp ect to thep atchs cen ter line (Y 2ax is .T hep robe 2feed is located at a distance (d p f

36、rom the p atchs bo ttom edge .F ig .7show s the equ ivalen t circu it of th is an 2tenna .In the m iddle p art of the p atch ,the cu rren t flow s like in no rm al p atchso it is rep resen ted by L C circu it andresonated at the in itial frequency .How ever ,at the edge p art of thep atch ,the cu rr

37、en t has to flow aroundthe slo ts and the length of the cu rren tp ath is increased .T h is effect can bem odeled as an additi onal series induc 2tance (L s 14,so the equ ivalen t cir 2cu it of the edge p art resonates at alow er frequency .T herefo re ,the an ten 2na changes from a single L C reson

38、an tcircu it to a dual resonan t circu it .T hese tw o resonan t circu its coup le together and fo rm a w ide bandw idth .Fo r ach ieving good i m p edance m atch ing over a w ide bandw idth ,the slit length (l is found to be abou t 018L ,and the slit w idth is abou t 0106W .T he sub strate th ickne

39、ss is tak 2en to be 11%of the w avelength of the cen ter frequency of 214GH z .T he design p aram eters of th is an tenna are as fo llow s :L =50mm ,W =105mm ,h =14mm ,l =40mm ,W 1=613mm ,W 2=1513mm ,d p =10mm .F ig .8show s the calcu lated retu rn lo ss fo r th is an tenna a 2gain st frequency ,it

40、is seen that tw o adjacen t resonan t m odes are excited at f o 1=2113GH z ,f o 2=215GH z .T he overall i m p edance bandw idth (fo r retu rn lo ss -10dB is abou t 800M H z con stitu ting abou t 33133%w ith resp ect to a cen ter frequency at 214GH z.T he an tenna gain p lo t fo r frequencies w ith i

41、n the i m p edance bandw idth is p resen ted in F ig .9,the p eak gain show n to be equal to 9125dB w ith a gain variati on less then 0134dB .F ig .10p lo ts the E 285北京邮电大学学报第27卷第 2 期 ABDAL I H A S et a l B andw id th Enhancem en t T echn iques fo r D ifferen t Shap es of . A 59 . m any w ireless c

42、omm un ica t ion sy stem s T he first configu ra t ion is designed fo r t rip le 2frequen 2 cy op era t ion a t 1183 GH z, 2116 GH z and 2174 GH z. T he second configu ra t ion ha s dua l2fre2 quency op era t ion a t 2113 GH z and 215 GH z w ith a to ta l bandw id th of 33133% cen tered . a round 21

43、4 GH z p lane and H 2 lane rad ia t ion p a t tern s a t the tw o resonan t frequencies. p - 20 dB in the H 2 lane p a t tern s . p p eak cro ss po la riza t ion rad ia t ion s a re less than - 40 dB in the E 2 lane p a t tern s, and less than p 3Conclus ion p robe 2fed sing le 2 a tch w ith a p a i

44、r of w ide slit s. T hese tw o configu ra t ion s can be app lied in p cro st rip an tenna s a re p resen ted, the p robe 2fed sing le 2 a tch w ith th ree sho rt ing p in s, and the p F ig. 8R etu rn lo ss fo r the E 2shap ed p a tch an tenna In th is p ap er, tw o d ifferen t techn iques fo r the

45、design of sing le 2 a tch sing le 2layer m i2 p F ig. 6P robe 2fed E 2shap ed p a tch an tenna F ig. 7Equ iva len t C ircu it of P rob 2fed E 2shap ed p a tch an tenna F ig. 9Ga in of E 2shap ed p a tch an tenna It is show n tha t the 60 北 京 邮 电 大 学 学 报 第 27 卷 References: 1 Poza r D M. M icro strip

46、an tenna s J . 2 V irga K L , R ahm a tt 2sam ii Y. p ackag ing J . 4 H erscovici N. P rop aga tion, 1998, 46: 8072812. 1980. 2002. 144 ( 5 : 3542358. 1995, 31: 1 31021 312. 1997, 45: 1 87921 888. J . P roceed ing of IEEE, 1992, 80: 79291. and P rop aga tion, 1998, 46: 2782283. L ow M icrow ave T heo ry and T echno logy, 3 Pap ao lym erou s I, D rayton R F , Ka teh i L P B. M icrom ach ined p a tch an tenna s IEEE T ran saction on A n tenna s N ew con sidera tion s in 5 B ah l I J , B ha rtia B. M icro strip an tenna s F ig. 10 H 2 lane and E 2 lane rad ia tion p a ttern s fo r