Tunable Slit Loaded Stacked Circular Microstrip Antenna for Multiband applications

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1 Intnational Jounal of Engining Rsac and Dvlomnt -ISSN: X, -ISSN: X,.ijd.com Volum 0, Issu 9 (Stmb 0, PP Tunabl Slit Loadd Stackd Cicula Micosti Antnna fo Multiband alications YUKTI ANAND and V K PANDEY Datmnt of Elctonics and Communication Engining, Noida Institut of Engining and Tcnology, Gat Noida Abstact:- In t snt ndavo a tunabl (fquncy agil stackd slit loadd cicula micosti antnna as bn sntd fo ilss systms. T fquncy agility as bn acivd by loading a vaacto diod. T antnna is abl to oat in fiv bands. On of ts bands os ov diffnt bands il ots a fixd at.96ghz,.79ghz,.308ghz and.603ghz. T bands a usful fo diffnt ilss alications. T matmatical modl sntd is vy accuat and givs cla ictu of facts aning in t antnna. Antnna aamts lik tun loss, sonant fquncy, gain, dictivity, co and coss ola attns av bn obtaind fom simulation and numically. T simulatd sults ag ll it t numical data. T gain of 6.78dBi and dictivity of 7.53 db as bn acivd fom t oosd tunabl stuctu. Kyods:- Stackd, slit, sonant fquncy, fquncy agil, cavity modl tc. I. INTRODUCTION Wit t advnt of diffnt svics, t nd fo multiband antnna is incasing day by day. Du to lo ofil, ligt igt, lo cost and intgation caability it MMICs, t micosti antnnas a bcoming oula fo ilss communication systms. But lo band idt and singl band of oation as bn innt oblm it tm. Also, ty suff fom lo gain and lo o andling caacity. Vaious tcniqus [-5] av bn volvd by sacs to nanc t bandidt. In [], to H-sa stackd micosti antnnas av bn analyzd using tansmission lin modl. In tis t stacking as bn lful to incas t adiation fficincy to 87% fom 3% and bandidt fom 0.% to 5.5%. An invtd-f antnna as bn sntd in [] it t gain of 5 dbi and bandidt of 5.8%. By soting t dgs of t stackd slot loadd ctangula micosti antnnas (RMSA, Boadband oation (imdanc bandidt of 76.5% is acivd [3]. In [] t auto movd coaxial fd in diffnt ositions to obtain cicula olaization in ctangula micosti antnna (RMSA. T antnna is usful fo satllit and tstial alication by o biasing of PIN diods. An E-sad atc is stackd in [5] on RMSA to imov t imdanc bandidt fom 33.8% to.9%. T a sval ot advantags of stackd micosti antnnas lik- stacking ovids many dgs of fdom lik ga btn lays fd oint, substat and sustat aamts. T coaxial fding tcniqu as bn xtnsivly usd in stackd atcs. T inductiv natu of t ob fd limits t bandidt of t antnna [6]. Rcntly t fquncy agil micosti antnnas av bn sn as solution to t lo bandidt [7-8]. Ty o ov diffnt fquncy bands at diffnt tim to cov a lag band. T to layd stackd micosti antnna as to sonant fquncis, by including an activ dvic btn gound lan and lo atc lo sonant fquncy could b vaid to o ov. A dual band oation is acivd in [8] by cutting to idntical notcs in RMSA. But loading of tunnl diod cass t u band of oation. Tis may b stod by using stakd stuctu. In t snt a, t vaacto loadd stackd cicula micosti antnna is analyzd and sntd fo multi band oation and may b vaid to ot bands fo ilss alication. T stuctu as fou bands of oation out of ic u t bands of t stuctu mains unaffctd il t lo band is agil in natu. T totical and simulatd tun loss, gain dictivity tc. a studid, t dtails of ic a givn in t folloing sctions. II. THEORETICAL CONSIDERATION In tis dsign t stackd atc as to lays of cicula micosti antnnas, lacd vtically and cnt alignd. T lo atc it adius a is suotd by a substat of dilctic constant ε and t u on it adius a siding on substat it dilctic constant ε. To ais of nao slits a cut diagonally in t u atc at 90 0 angls. T idt of ac slit is mm, t lngt of slit along oizontal axis is 5 mm and tat along vtical axis is 0 mm. T ticknss of t lo substat lay is and tat of t u is, bot.6 mm. In t snt dsign bot lays a filld it FR substat it lativ dilctic constant of 60

2 Tunabl Slit Loadd Stackd Cicula Micosti Antnna fo Multiband alications.. A vaacto diod is mbddd btn lo cicula atc (LCP and gound lan. T cnt conducto of coaxial ob is lctically connctd to t u cicula atc (UCP toug a ol in t lo atc as son in fig.. T 3D vi of t stuctu fom full av lctomagntic simulation softa ADS is son in figu. T numical analysis of antnna is sntd in fiv ats. Fist at dscibs dsign of u cavity it lo atc as gound lan. Scondly, an analysis is givn to incooat t fou slits in t u atc.. In t tid at, t lo cavity as bn analyzd it sustat, nglcting ffct of u atc. In t fout at t combind ffct of lo and u cavity i.. stackd antnna is invstigatd. Lastly, vaacto diod loadd stackd cicula micosti antnna as bn invstigatd. T totical and simulatd sults a found and t is good agmnt btn tm. a UCP a LCP UCP ρ LCP Vaacto Diod Gound Pob fd Fig. : Stuctu of oosd antnna Fig : 3D vi fom ADS Analysis of u atc T sonant fquncy of u atc is dtmind by taking substat igt [9], sinc lo atc acts as gound lan fo u atc. T siz of lo atc is small and acts as finit gound lan. Tis assumtion causs o in t modl, sinc lo atc dos not ovid sufficint gound. T inut imdanc of u cavity is givn as 6

3 Tunabl Slit Loadd Stackd Cicula Micosti Antnna fo Multiband alications Zin ( jc R 6 jl W sistanc R, caacitanc C and inductanc L a quivalnt cicuit comonnts fo cicula micosti antnna xssd as aalll combination fo TM n mod. T sonanc sistanc (R is givn by [0] R G T J ( k n J ( ka n ( W ρ is ob osition fom cnt, J n is t fist kind of Bssl function of od n it agumnt kρ o ka, G T is total conductanc fo u cavity associatd it dilctic loss, adiation loss, and conduction loss. T caacitanc associatd it u cavity atc is givn by and inductanc L of u lay is givn as L C Q T f sr R fsqt ( W Q T is total quality facto [] of u cavity, ic includs adiation loss, dilctic loss and conductanc loss. Tn sonant fquncy (f s of u cavity cicula micosti antnna is givn [] by f s c mn (5 a ff ff W c is vlocity of ligt in f sac, α mn is m t zo of fist kind Bssl function of od n, a ff is ffctiv adius of t u atc and ε ff is ffctiv mittivity [] of u substat considing finging ffct of u atc. Analysis of slit loadd Cicula micosti antnna T ffct of slits may b incooatd in t dsign by taking t multil adius of t cicula micosti atc. Du diffnt lngts of t slits, t ould b t sonant fquncis [3] T i t sonant fquncy may b givn as W P is ffctiv cicumfnc du to slits and is govnd by f i P Pi a.8c P ff ( (3 (6 a ln.776 In t abov quation Pi is ysical cicumfnc associatd to diffnt sonant fquncy and is givn by a a Pi a a... fo i l x... fo i l... 3 y fo i l lx... fo i y Fo ac valu of sonant fquncis givn in quation (6 t associatd ysical adius is calculatd by dividing quation (8 by. Analysis of lo atc Lo cicula atc is analyzd as cicula micosti antnna it sustat and nglcting t ffct of u atc. On o mo dilctic lay abov adiating atc distubs finging filds tus canging t ffctiv adius of lo atc. Rsonant fquncy of ctangula micosti antnna it sustat as bn calculatd in [] taking filling faction into considation. In tis, an antnna systm it on o mo / (7 (8

4 Tunabl Slit Loadd Stackd Cicula Micosti Antnna fo Multiband alications 63 sustat is sntd as antnna it on substat it sam adiation caactistics. Moov, t fomulation ovidd in [] along it analysis caid out in [5] is usd to analyz t snt oblm mo accuatly. T ffctiv dilctic constant of quivalnt substat is givn as ] ( { ( ( ][ ( { [ ( ff (9 W ln( (0 3 ( 3 sin (0.5 cos ln g g g g ( ln (3 actan g ( ln ( ( ff ( ff (6 ( a (7 T aamts and ε a calculatd by itation mtod [] it initial valu ε = ε and ε ff = ε. In t abov quation (7 is idt of RMSA quivalnt to CMSA it sam adiation caactistics [6]. Ts quations may b calculatd by assuming qual finging fild fo bot stuctus. Wn t lativ dilctic constant of sustat is gat tan tat of substat, t sufac av may b ducd to a ctain xtnt by coosing aoiat ticknss. To accommodat tis, a n dilctic constant is dfind as ff (8 No ffctiv adius of LCP is calculatd as ( q a a ff (9

5 Tunabl Slit Loadd Stackd Cicula Micosti Antnna fo Multiband alications In tis q is calculatd as givn in [] in quations (9-( t sult of abov quation (7 is usd. Using a ff as calculatd in quation (6, t inut imdanc of LCP Z in is calculatd. T antnna is assumd to b dg fd in abov calculation. Stakd Cicula Patc T is no vaiation of lctic fild in z diction so total lctic fild is sum of t lctic filds in LCP and UCP. Moov, LCP is sntd as aalll combination of a sistanc (R, an inductanc (L and a caacitanc (C. T quivalnt cicuit of stackd micosti antnna may b sntd as sis combination of inut imdancs of t to antnnas i.. LCP and UCP as son in fig. 3. Hnc Z Z Z (0 in in in Vaacto Diod Intgatd Stackd Micosti Patc: T vaacto diod is connctd btn LCP and gound lan and is ositiond oosit to coaxial fd. T diod is kt at t dg of t antnna. T quivalnt cicuit of vaacto diod is son in fig.. It contains a sis sistanc (R s du to smiconducto matial, inductanc (L s du to connction fom xtnal tminal, a junction caacitanc (C j du to sac cag in dltion gion and ackaging caacitanc (C. T junction caacitanc of vaacto diod vais it vs bias as C j C C j0 is zo bias junction caacitanc, v is bias voltag, V T is built in voltag (tsold voltag and n is a constant (tuning slo ic dnds uon doing ty. Fo abut junction t valu of n is lss tan 0.5 and fo y-abut junction its valu is takn mo tan 0.5. T imdanc of diod is calculatd fom fig. as Z Z jc Z ( Z s d s j0 v V T n /( s ( R jl / jc (3 s s ( j Hnc total inut imdanc of vaacto loadd stackd cicula micosti antnna as son in fig. 5 is givn as Z Z Z Z Z Z ( and tun loss is givn as int in in d /( in d RL 0log (5 W flction cofficint (Γ fo coaxial ob of 50 oms caactistic imdanc is givn as ( Z int 50 ( Z int 50 (6 Z in LCP Z in R L C UCP Z in R L C Fig. 3: Equivalnt cicuit of stackd CMSA 6

6 Tunabl Slit Loadd Stackd Cicula Micosti Antnna fo Multiband alications R s C C j Z d L s Fig. : Equivalnt cicuit of Vaacto diod Z d R L C Z int R L C Fig. 5: Equivalnt cicuit of stackd CMSA loadd it vaacto diod III. DESIGN PARAMETERS T stackd cicula micosti antnna is dsignd to oat on to sonant fquncis -. GHz and 3.5 GHz itout any slit in t u atc. T motiv is to dsign an antnna tat could oat fo WiMAX as ll as on of PCS, DCS and UTMS bands. Fo ts oating fquncis t antnna dsign aamts a givn in Tabl I. T adius fo UCP is calculatd assuming LCP as gound lan. Commcially availabl vaacto diod (MA 673 is takn to simulat t antnna. Fo calculation, t valus of quivalnt disct comonnts ic a givn in tabl II a usd. Tabl I Stackd CMSA Scification Paamts Valu Radius of LCP (a 6mm Radius of UCP (a 6.5mm Higt of LCP(.6mm Higt of UCP(.6mm Rlativ dilctic constant of. (FR substat & sustat (ε = ε Widt of slit ( mm Lngt of slits (lx, ly 5mm, 0mm Loss Tangnt (tan δ

7 Tunabl Slit Loadd Stackd Cicula Micosti Antnna fo Multiband alications Tabl II Vaacto diod scification Paamts Valu Modl MA673 Matial GaAs Junction Ty Hy abut Sis Rsistanc (R s 0.om Sis inductanc (L s 0.nH Pak Junction caacitanc(c 0 6f Tsold voltag (V T.Volts Packag caacitanc (C 0.3f IV. RESULTS AND DISCUSSIONS Fig. 6: vaiation of al and imaginay at of inut imdanc it fquncy fom MATLAB fo SLSCMSA Fig. 6 sos comutd al and imaginay at of inut imdanc fom MATLAB fo slit loadd stackd cicula micosti antnna (SLSCMSA itout loading any vaacto diod. T figu sos tat t a fiv sonanc fquncis in t stackd antnna at.6339ghz,.96ghz,.79ghz,.308ghz and.603ghz. T lost sonant fquncy cosonds to lo CMSA il igst on cosonds to CMSA xcluding all t fou slits. Figu 7 sos imdanc vaiation it fquncy fom simulation softa. T sonant fquncis fom t ga a.5ghz,.06ghz,.ghz and.56ghz. It is noticabl tat t to lo sonant fquncis coincid at.5ghz. T calculatd and simulatd sonant fquncis a vy clos to ac ot. 66

8 Tunabl Slit Loadd Stackd Cicula Micosti Antnna fo Multiband alications Fig. 7: vaiation of al and imaginay at of inut imdanc it fquncy fom ADS fo SLSCMSA Fig. 8: Rtun loss vaiation it fquncy fom MATLAB fo SLSCMSA Fig. 9: Rtun loss vaiation it fquncy fom ADS fo SLSCMSA Figus 8 and 9 so comutd and simulatd tun loss vaiation it fquncy. 67

9 Tunabl Slit Loadd Stackd Cicula Micosti Antnna fo Multiband alications Rvs Bias Voltag, volts Figu 0: Vaiation of Junction caacitanc it vs bias voltag Figu 0 sos vaiation of junction caacitanc it vs bias of vaacto diod. A st vaiation in t junction caacitanc is obsvd aound V and t ak valu of junction caacitanc is 6f. Fig. : Imdanc vaiation it fquncy fo Vaacto loadd antnna at 0V fom MATLAB Fig. : Imdanc vaiation it fquncy fo Vaacto loadd antnna at 0V fom ADS 68

10 Tunabl Slit Loadd Stackd Cicula Micosti Antnna fo Multiband alications Figu and so t vaiation of inut imdanc of vaacto diod loadd antnna at 0V vs bias. T lost sonant fquncy ic is associatd it lo atc is siftd toads lo sid at.7ghz (simulatd and.7ghz (calculatd. Figu 3: Rtun loss vaiation of vaacto diod loadd micosti antnna at 0 V fom MATLAB Figu : Rtun Loss vaiation of Vaacto diod loadd micosti antnna at 0 V fom ADS Figus 3 and so tuns loss vaiation of t Vaacto loadd SLSCMSA at 0V vs bias. Hig od mod may b obsvd na GHz ic is associatd it lo atc. Tis mod also movs toads lo sid of t fquncy sctum as vs bias is vaid. Figu 5 and 6 so t vaiation of inut imdanc of vaacto diod loadd antnna at 0.5V vs bias. T lost sonant fquncy ic is associatd it lo atc is siftd toads lo sid at.39ghz (simulatd and.55ghz (calculatd. It is noticabl tat t ot bands main fixd. 69

11 Tunabl Slit Loadd Stackd Cicula Micosti Antnna fo Multiband alications Figu 5: Inut imdanc vaiation of vaacto diod loadd micosti Antnna at 0.5 V fom MATLAB Fig. 6: Inut imdanc vaiation of Vaacto diod loadd micosti antnna at 0.5 V fom ADS\ Figus 7 and 8 so tuns loss vaiation of t Vaacto loadd SLSCMSA at 0.5 V vs bias. Hig od mod may b obsvd na. GHz ic is associatd it lo atc. T movmnt of ig od mod may b sn again toads ig sid of t fquncy sctum as vs bias is incasd. Fig. 7: Vaiation of comutd tun loss it fquncy at 0.5V fo Vaacto diod loadd SLSCMSA 70

12 Tunabl Slit Loadd Stackd Cicula Micosti Antnna fo Multiband alications Fig. 8: Vaiation of simulatd tun loss it fquncy at 0.5V fo Vaacto diod loadd SLSCMSA Fig. 9: Dictivity and gain vaiation at at.ghz Fig. 0: Co and coss ola adiation attn at.ghz 7

13 Tunabl Slit Loadd Stackd Cicula Micosti Antnna fo Multiband alications Figu 9 sos gain dictivity otis of t tunabl oosd antnna. T ga sos ts aamts it sct to lvation tta. It may b obsvd tat t ak occus at 0 0 indicating a boadsid adiation attn. Maximum dictivity of t antnna is found to b 7.533dB and maximum gain is 6.78dBi. Ts aamts a simila to an odinay stackd micosti antnna i.. no ffct of loading of vaacto diod is sn. Figu 0 sos co-ola and coss ola adiation attn of t oosd antnna. Again a boadsid adiation attn is confimd. T coss ola attn sussion of mo tan db is acivd in t antnna suggsting a linaly olaizd adiation attn. Tabl III sos comaison of sonant fquncis fom MATLAB and ADS. T sults a in clos agmnt. Tabl III: Comaison of sonant fquncis fom MATLAB and ADS itout vaacto diod f f f3 f f5 MATLAB ADS it vaacto at 0V bias MATLAB ADS it vaacto at 0.5V MATLAB ADS V. CONCLUSION A vaacto diod and slit loadd stackd cicula micosti antnna as bn dsignd and analyzd using xtndd cavity modl. Fou slit on t u atc ovid multiband oation to t antnna. Tuning oty as bn acivd using vaacto diod ic maks antnna suitabl fo ilss communication lik WiMAX, UTMS and PCS bands. T gain, dictivity, fficincy tc. av bn lik any nomal stackd cicula micosti antnna i.. t fquncy agility as bn acivd itout any significant loss in its ot adiation otis. T antnna may oat at all bands simultanously vn aft vaacto loading. REFERENCES []. Jaum Angua, Lluis Boada, Cals Punt, Camn Boja and Jodi Sola. (00. Stackd H-Sad Micosti Patc Antnna. IEEE Tans. on Antnna and Poag. Vol. 5 (, []. Moammod Ali, Abu T. M. Saym and Vijay K. Kunda. (007. A Rconfiguabl Stackd Micosti Antnna fo Satllit and Tistial Link. IEEE Tans. on Vicula Tcnology. Vol. 56 (, [3]. P. K. Singal, Baana Daniam and Smita Banj. (003. A stackd Squa Patc Slottd Boadband Micosti Antnna. Jounal of Micoavs and Otolctonics. Vol. 3 (, []. Nasimuddin. (007. Dsign of Wid band Ciculaly Polaizd Stackd Micosti Antnna it Dilctic Cov using Singl Fd. Micoav and Otical tcnology Ltts. Vol. 9 (, [5]. Ban-Long Ooi, Sn Qin and Mook-Sg Long. (00. Novl Dsign of Boad Band Stackd Patc Antnna. IEEE Tans. on Antnna and Po. Vol. 50 (0, [6]. K. M. Luk, K.F. L and Y. L. Co. (998. Poximity-could stackd cicula-disc micosti antnna it slots. Elctonics Ltts. Vol. 3 (5, [7]. Ganga Pasad Pandy, Binod Kuma Kanaujia and Sunda K. Guta Doubl MOS Loadd Cicula Micosti Antnna fo Fquncy Agil. Poc. IEEE Int. Conf. Alid Elctomagntic Confnc. Kolkata, India. [8]. Ganga Pasad Pandy, Binod Kuma Kanaujia, Sunda K. Guta and S. Jain. 0. Analysis of tunnl Diod Loadd H-sad Micosti Antnna. Intnational Jounal of Radio Fquncy Idntification Tcnology and Alication. Vol. 3 (,.-59. [9]. Javi G omz-tagl and Cistos G. Cistodoulou. (997. Extndd Cavity Modl Analysis of Stackd Micosti Ring Antnnas. IEEE Tansactions on Antnnas and Po. Vol. 5(, [0]. I. J. Bal and P. Batia, Micosti Antnnas, Atc Hous, Ddam, MA, 980. []. F. Abboud, J. P. Damiano and A. Painik. (990. A n modl fo calculating t inut imdanc of coax-fd cicula micosti antnnas it and itout ai gas. IEEE Tansaction on Antnna and Poagation. Vol. 38(,

14 Tunabl Slit Loadd Stackd Cicula Micosti Antnna fo Multiband alications []. Dbatos Gua. (00. Rsonant Fquncy of Cicula Micosti Antnnas it and itout Ai Gas. IEEE Tansaction on Antnna and Poagation. Vol. 9(, [3]. D. D. Kisna, M. Goikisna, C. K. Aanandan, P. Moanan and K. Vasudvan. (008. Comact Dual Band Slot Loadd Cicula Micosti Antnna it a Sustat. Pogss In Elctomagntics Rsac (PIER, Vol. 83, []. Jnif T. Bnad and Caolyn J. Tousgnant. (999. Rsonant Fquncis of Rctangula Micosti Antnnas it flus and Sacd dilctic Sustats. IEEE Tansaction on Antnna and Poagation, Vol. 7(, [5]. Dbatos Gua and Jaad Y. Siddiqui. (003. Rsonant Fquncy of Micosti antnna Covd it Dilctic Sustat. IEEE Tansaction on Antnna and Poagation, Vol. 5 (7, [6]. J. R. Jams and P. S. Hall, Handbook of Micosti Antnnas, Pt Pginus, London, UK, 989. [7]. ADS Simulation softa v0. 73

School of Electrical Engineering. Lecture 2: Wire Antennas

School of Electrical Engineering. Lecture 2: Wire Antennas School of lctical ngining Lctu : Wi Antnnas Wi antnna It is an antnna which mak us of mtallic wis to poduc a adiation. KT School of lctical ngining www..kth.s Dipol λ/ Th most common adiato: λ Dipol 3λ/