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1 Chalmrs Publication Library An E-band Cylindrical Rflctor Antnna for Wirlss Communication Systms This documnt has bn downloadd from Chalmrs Publication Library (CPL. It is th author s vrsion of a work that was accptd for publication in: 7th Europan Confrnc on Antnnas and Propagation, EuCAP 2013, Gothnburg, Swdn, 8-12 April 2013 Citation for th publishd papr: Yang, J. ; Papagorgiou, I. ; Drnryd, A. (2013 "An E-band Cylindrical Rflctor Antnna for Wirlss Communication Systms". 7th Europan Confrnc on Antnnas and Propagation, EuCAP 2013, Gothnburg, Swdn, 8-12 April 2013 Downloadd from: Notic: Changs introducd as a rsult of publishing procsss such as copy-diting and formatting may not b rflctd in this documnt. For a dfinitiv vrsion of this work, plas rfr to th publishd sourc. Plas not that accss to th publishd vrsion might rquir a subscription. Chalmrs Publication Library (CPL offrs th possibility of rtriving rsarch publications producd at Chalmrs Univrsity of Tchnology. It covrs all typs of publications: articls, dissrtations, licntiat thss, mastrs thss, confrnc paprs, rports tc. Sinc 2006 it is th official tool for Chalmrs official publication statistics. To nsur that Chalmrs rsarch rsults ar dissminatd as widly as possibl, an Opn Accss Policy has bn adoptd. Th CPL srvic is administratd and maintaind by Chalmrs Library. (articl starts on nxt pag

2 An E-band Cylindrical Rflctor Antnna for Wirlss Communication Systms Ioannis Papagorgiou, Andrs Drnryd, Lars Manholm andjianyang Kongsbrg Norspac AS, Hortn, Norway Ericsson AB, Gothnburg, Swdn Chalmrs Univrsity of Tchnology, Gothnburg, Swdn Abstract Th incrasing dmand of radio links with high data rats is satisfid by th allocation of nw frquncy spctrum. A novl cylindrical rflctor antnna is dsignd to oprat in th E- band (71 86 GHz, which was alrady allocatd in 2003 for radio link applications. Prsntd simulation rsults ar prliminary and th dirctivity of th antnna at th cntr frquncy is calculatd to b 41.4 dbi with an aprtur fficincy of 60% or -2.2dB. 1 Indx Trms cylindrical rflctor antnna; hat fd; paralll plat; millimtr wavs; E-band I. INTRODUCTION During th last yars th nd of nw srvics and communication systms ld to an ovrcrowdd frquncy spctrum. Th allocation of th E-band (71 86 GHz nabls a nw frquncy spctrum that has a grat potntial for point-topoint wirlss links and wirlss backhaul applications. Ths wirlss links ar capabl of rplacing fibr optics, bcaus thy ar lss costly and asir to dploy [1]. Th E-band antnnas ar rquird to b mchanically small, of high gain and suitabl for intgration with th radio. Th ETSI standard rquirs a minimum antnna gain of 38 dbi, and radiation pattrn nvlop classs 2, 3 and 4 ar rlasd for diffrnt applications [2]. Svral typs of antnnas hav alrady bn dvlopd in th E-band and thy ar usd for diffrnt applications [3] [6]. Rflctor antnnas ar vry attractiv candidats for us at high frquncis, bcaus thy hav high gain and low loss. In this papr, a nw quadratical rflctor antnna is prsntd, which is partly inspird by hat-fd rflctor antnnas [7] [11]. Th main advantags of th nw antnna compard with th hat-fd rflctor antnna ar low manufactur cost sinc thr is no dilctric had involvd and highr gain. A prliminary dsign of th cylindrical rflctor antnna with a rctangular aprtur is prsntd in th following sctions. II. ANTENNA STRUCTURE Th configuration of th proposd cylindrical rflctor antnna is shown in Fig. 1. Th cylindrical rflctor is illuminatd by a corrugatd linar hat fd, which is fd by a paralll plat structur. Insid th paralll plat thr is an 1 This work was prformd at Ericsson AB in Gothnburg as a mastr thsis projct of Chalmrs mastr s program Wirlss and Photonics Enginring. Fig. 1. Cylindrical parabolic rflctor antnna on-dimnsional rflctor antnna, which is illuminatd by a hat fd. This hat fd is fd by a standard WR-12 rctangular wavguid, oprating in th E-band. Th antnna has a squar aprtur and th lngth of th sid is d = mm. Th focal lngth for both rflctors is st as F =32.3 mm, and th antnna dpth is Δz = mm. Thrfor, th half subtndd angl is 105. Th hat insid th paralll plat has no corrugations and dos not nd any dilctric support, bcaus it is alrady supportd by th paralll plats. Th dominant TE 10 mod propagats in th WR-12 wavguid. Th spacing btwn th hat and th opn nd of th wavguid should b qual to or largr than half a wavlngth, in ordr to avoid th propagation mod bing cut-off. Th corrugatd cylindrical hat fd that is locatd on top of th paralll plat is dsignd in ordr to achiv low sidlobs in th radiation pattrn. Th dpth of ach corrugation is slctd to b λ 0 /4, whr λ 0 is th wavlngth at th cntr frquncy, and thr ar thr corrugations on ach sid of th hat. III. THEORY AND FORMULATIONS Th far-fild function of a rctangular cylindrical rflctor can b calculatd analytically, assuming that th aprtur

3 distribution is th truncatd Gaussian. Th gnral xprssion of th far-fild function of an aprtur distribution can b writtn on its Fourir transform as [12] G(θ, φ = 2C k cos 2 ( θ 2 (cosφˆθ sinφˆφ Eax 2C k cos 2 ( θ 2 (sinφˆθ cosφˆφ Eay, (1 whr C k = jk/(4π. For y-polarizd antnna, th far-fild function is proportional to E ay (ksinθcosφ, ksinθsinφ = Eay (kˆx ˆr,kˆy ˆr = A(kˆx ˆr B(kˆy ˆr with A(kˆx ˆr = B(kˆy ˆr = d/2 d/2 (x/ρα2 (jkxˆx ˆr dx (y/ρα2 (jkyˆy ˆr dy whr ρ α = d/(2 0.4ln10, for 10 db of illumination tapr. Th maximum of th absolut of th far-fild is proportional to th maximum of th on dimnsional Fourir transforms and this occurs whn θ =0, i.., G max = Eay (kˆx ˆr,kˆy ˆr max = A(0 B(0 = πρ 2 αrf 2 ( d whr rf(x = 2 x π dx is th rror function. 0 t2 Th total powr of th far-fild function is qual to th squar of th aprtur intgral function, P = = d/2 d/2 E ay (x, y 2 dxdy d/2 d/2 x 2( ρα 2 2( y ρα 2 dxdy = π 2 ρ2 αrf 2 ( 2d. Thrfor, th dirctivity of a rctangular aprtur can b calculatd by D = 4π G 2 max = 4π rf 4 ( d P λ 2 rf 2 ( (6 2d IV. BLOCKAGE OF THE CYLINDRICAL REFLECTOR Th total blockag loss of th cylindrical rflctor is th rsult of th blockag from both hat fds that illuminat th rflctors, which lads to a highr blockag loss than that of a typical hat fd. Th blockag at th first dimnsion occurs from th hat fd insid th paralll plat and th blockag at th scond dimnsion occurs from th linar hat fd that is xtndd (2 (3 (4 (5 Fig. 2. Blockag in th rctangular aprtur of th cylindrical rflctor (a is th total ara of th aprtur, b is th ara that is blockd along th two dimnsions and corrsponds to th gry ara of th figur and c is th black common blockd ara at th cntr along th aprtur of th paralll plat. A schmatic of th blockag in th rctangular aprtur is shown in Fig. 2, whr a squar aprtur and th sam siz of hat fds ar assumd for simplicity. Th dirctivity of th antnna including only th blockag loss can b calculatd approximatly by th dirctivity of th antnna without th blockag minus th dirctivity from th ara which is blockd. Th dirctivity from th common ara in th cntr should b addd, bcaus othrwis it would b subtractd twic in Eq. (12. whr D b = 4π G a 2G b + G c 2 max P a 2P b + P c (7 G a = πρ 2 αrf 2 ( d (8 G b = E ay (kˆx ˆr,kˆy ˆr max = A(kˆx ˆrB(kˆy ˆr = d/2 h/2 h/2 x ( = πρ 2 αrf( d rf( h G c = A(kˆx ˆrB(kˆy ˆr = ρα 2 y ( ρα 2 dxdy h/2 h/2 ( h ρα 2 y ( ρα 2 dxdy h/2 h/2 = πρ 2 αrf 2 ( h (9 (10 In a similar way th powr of ach aprtur ara is calculatd and it is found to b

4 50 30 H plan ETSI class 3 ETSI class E plan Dirctivity (dbi Dirctivity (dbi θ (dg ETSI class 3 ETSI class θ (dg Fig. 3. Calculatd H-plan of th cylindrical rflctor for f = 78.5 GHz Fig. 4. Calculatd E-plan of th cylindrical rflctor for f = 78.5 GHz P a = π 2d 2 ρ2 αrf 2 ( P b = π 2d 2h 2 ρ2 αrf( rf( P c = π 2h 2 ρ2 αrf 2 ( (11 Thrfor, th total dirctivity of th antnna including th blockag can b approximatd by Dirctivity (dbi D plan ETSI class 3 ETSI class 2 D b = 8π2 ρ 2 α λ 2 Finally, th blockag fficincy is rf( d rf( h 4 (rf( 2d rf( 2h 2. (12 b = D b D. (13 V. SIMULATION RESULTS Th radiation pattrns of th cylindrical antnna wr simulatd by using both HFSS [13] and G2DMULT [14]. G2DMULT is a gnral algorithm basd on th S2DS tchniqu that calculats th spctral Grns functions of 2-D multirgion structurs by using th mthod of momnt (MoM. G2DMULT maks us of th Fourir transform of th 3-D xcitations in th uniform dirction of th 2-D structur to arriv into a spctral domain problm that can b solvd by 2- D spatial tchniqus. Thrfor, instad of solving a vry larg 3-D problm dirctly, G2DMULT provids a vry fficint simulation for 2-D cylindrical gomtry problms [15] [19], such as also in th cas of this work. Th simulatd radiation pattrns in H, E and 45 plans of th antnna at th cntr frquncy of 78.5 GHz, using G2DMULT, ar plottd in Figs. 3 5, rspctivly. It can b sn that th H plan pattrn almost satisfis th ETSI class 2 rquirmnt, whil th E plan pattrn dos not, and th 45 plan pattrn satisfis vn th ETSI class 3 rquirmnt. Fig. 5. G2DMULT gomtry for th cross sction of th 1D rflctor (E- Fig. 6. plan θ (dg Calculatd 45 -plan of th cylindrical rflctor for f = 78.5 GHz Th gomtry of th antnna in G2DMULT is shown in Figs. 6 7 for th E and H plan rspctivly. Th 45 plan radiation pattrn in Fig. 5 is calculatd basd on th simulatd radiation pattrns in E and H plans. Th complt cylindrical rflctor antnna could not b simulatd as a whol in th softwars, bcaus of th complxity of th dsign and computr mmory limitations. Thrfor, th

5 Fig. 7. G2DMULT gomtry for th cross sction of th cylindrical rflctor (H-plan Fig. 9. E, H and 45 -plan of cylindrical rflctor for f = 78.5 GHz 42 Fig. 8. On quartr of th cylindrical rflctor as simulatd in HFSS 41.5 rsults wr calculatd by two diffrnt mthods. Th first mthod was to simulat th cross sction of th on-dimnsional cylindrical rflctor and th cros sction of th cylindrical rflctor, thus th E and H plan, rspctivly, by using G2DMULT. Thn, th 45 -plan is calculatd. Th othr mthod was to dsign on quartr of th antnna as it is shown in Fig. 8 in HFSS by xploiting th symmtry in E and H plans. In that way all th plans could b simulatd and thy ar plottd in Fig. 9. Th simulation rsults from both mthods sm to agr with ach othr and th 45 plan is th only on that satisfis both class 2 and class 3 ETSI rquirmnts. Thrfor, th antnna should b mountd in such a way that th 45 plan is in th horizontal plan. Finally, th dirctivity of th antnna has bn obtaind by two mthods: 1 simulation in both softwars; 2 calculation by subtracting its sub-fficincis from th thortical maximum dirctivity. Th rsults ovr th E-band ar plottd in Fig. 10, and thy diffr with up to 1dB. Th total aprtur fficincy is calculatd by: ap = sp ill φ b pol (14 whr, sp =0.987, ill =0.74, φ =0.953, b =0.866 and pol =1for th cntr frquncy and it is found to b ap =0.6. Dirctivity (dbi 41.5 Calculatd by sub fficincis Frquncy (GHz Fig. 10. Dirctivity ovr th E-band obtaind by two mthods: 1 simulation; 2 D = D max sp φ b ill,whr sp is th spillovr loss, φ th phas loss, b th blockag loss and ill th illumination loss. Apart from th blockag fficincy that is alrady dfind in a prvious sction th rst of th sub fficincis ar calculatd by quations from [20]. VI. CONCLUSION A nw E-band antnna concpt has bn proposd for wirlss backhaul solution to high data rat links. This cylindrical rflctor antnna is compact, provids high gain and it is asir and chapr to manufactur in comparison with circular rflctor antnnas. Both th dirctivity and th sidlob lvl satisfy th ETSI rquirmnts, thus this antnna has a grat potntial to b usd in th th nxt gnration of mobil ntworks.

6 REFERENCES [1] V. Dyadyuk, Y. J. Guo, and J. D. Bunton, Multi gigabit wirlss communication tchnology in th E band, in IEEE Wirlss VITAE 2009, pp , [2] ETSI EN , Fixd radio systms; Charactristics and rquirmnts for point-to-point quipmnt and antnnas; Part 4-2: Antnnas; Harmonizd EN covring th ssntial rquirmnts of arcticl 3.2 of R&TTE dirctiv, pp. 2 35, [3] M. Guy, H. Ouslimani, S. Burokur, A. Priou, Y. Ltstu, and A. Bayon, Antnna array for point-to-point communications in E-band frquncy rang, IEEE, pp , [4] D. Nculoiu, S. I. En, A. A. Mullr, and C. Buiculscu, Elctromagntic modling and dsign of 77 GHz antnnas in LTCC tchnology, 2009 IEEE, pp , [5] Y. Kimura, K. Fukazawa, and J. Hirokawa, Low sidlob singl-layr slottd wavguid arrays at 76 GHz band, IEICE transactions on communications, vol. 84, no. 9, pp , [6] F. Schafr, F. Gall, G. Landrac, and M. Ny, Optimum rflctor shaps for anticollision radar at 76 GHz, Microwav and Optical tchnology lttrs, vol. Vol. 24, No. 6, pp. 0 4, March [7] P.-S. Kildal, Th hat-fd: A dual-mod rar-radiating wavguid antnna having low cross polarization, IEEE Transactions on Antnnas and Propagation, vol. 35, no. 9, pp , [8] P.-S. Kildal and J. Yang, FDTD optimizations of th bandwidth of th hat fd for MM-wav rflctor antnnas, IEEE Antnnas and Propagation Socity Intrnational Symposium, vol. 4, pp , [9] M. Dnstd, T. Ostling, J. Yang, and P. S. Kildal, Tripling bandwidth of hat fd by gntic algorithm optimization, in 2007 IEEE Antnnas and Propagation Socity Intrnational Symposium, pp , [10] W. Wi, J. Yang, T. Ostling, and T. Schafr, A nw hat fd for rflctor antnnas ralizd without dilctrics for rducing manufacturing cost and improving rflction cofficint, IET Microwavs, Antnnas & Propagation, vol. 5, no. 7, pp , July, [11] G. E. Gtrud, J. Yang, T. Ostling, and P. Brgmark, Dsign and optimization of a compact widband hat-fd rflctor antnna for satllit communications, IEEE Transactions on Antnnas and Propagation, vol. 61, no. 1, pp , Jan [12] P.-S. Kildal, Foundations of Antnnas - A unifid approach for lin-ofsight and multipath. Studntlitratur, [13] htttp:// [14] P.-S. Kildal, Dsctiption of G2DMULT momnt mthod algorithm for calculating spctral Grn s functions of cylindrical multiconductor stucturs of arbitary cross sction, in 1999 IEEE Antnnas and Propagation Socity Intrnational Symposium, vol. 4, pp , [15] J. Yang, B. Lindmark, and P.-S. Kildal, Studis of cylindrical bas station antnnas for futur communication systms by using G2DMULT, in 9th COST mting and workshop on smart antnnas, Gothnburg, Swdn, May 2001, [16] J. Yang and P.-S. Kildal, Prsntation of th spctral lctric and magntic fild intgral quations usd in G2DMULT for analyzing cylindrical structurs of multi-matrial rgions, Microwav Opt. Tch. Ltt., vol. 34, no. 2, pp , 20 July [17] J. Yang, J. Carlsson, P.-S. Kildal, and C. Carlsson, Calculation of slf impdanc and radiation fficincy of a dipol nar a lossy cylindr with arbitrary cross sction by using th momnt mthod and a spctrum of two-dimnsional solutions, Microwav Opt. Tch. Ltt., vol. 32, no. 2, pp , 20 Jan [18] J. Yang and P.-S. Kildal, A fast algorithm for calculating th radiation pattrn in th longitudinal plan of antnnas with cylindrical structur by applying asymptotic wavform valuation in a spctrum of twodimnsional solutions, IEEE Trans. on Antnnas Propagat., vol. 52, no. 7, pp , July, [19] J. Yang, U. Caldbrg, P.-S. Kildal, and M. Ng, A fast mod analysis for wavguids of arbitrary cross sction with multipl rgions by using a spctrum of two-dimnsional solutions and asymptotic wavform valuation, IEEE Trans. on MTT, vol. 52, no. 6, pp , Jun [20] P.-S. Kildal, Aprtur fficincy and linar phas cntr of parabolic cylindrical rflctor antnna, IEEE Transactions on Antnnas and Propagation, vol. 32, no. 6, pp , Jun 1984.