Aalborg Universitet. Published in: Microwave & Optical Technology Letters. DOI (link to publication from Publisher): /mop.

Transcription

1 Alborg Universitet A Compct UWB Bndpss Filter With WLAN Rejection Using Slot Ring Resontor Shen, Ming; Tong, Tin; Jensen, Ole Kiel; Mikkelsen, Jn Hvolgrd; Lrsen, Torben Published in: Microwve & Opticl Technology Letters DOI (link to publiction from Publisher): /mop Publiction dte: 2010 Document Version Erly version, lso known s pre-print Link to publiction from Alborg University Cittion for published version (APA): Shen, M., Tong, T., Jensen, O. K., Mikkelsen, J. H., & Lrsen, T. (2010). A Compct UWB Bndpss Filter With WLAN Rejection Using Slot Ring Resontor. Microwve & Opticl Technology Letters, 52(9), DOI: /mop Generl rights Copyright nd morl rights for the publictions mde ccessible in the public portl re retined by the uthors nd/or other copyright owners nd it is condition of ccessing publictions tht users recognise nd bide by the legl requirements ssocited with these rights.? Users my downlod nd print one copy of ny publiction from the public portl for the purpose of privte study or reserch.? You my not further distribute the mteril or use it for ny profit-mking ctivity or commercil gin? You my freely distribute the URL identifying the publiction in the public portl? Tke down policy If you believe tht this document breches copyright plese contct us t vbn@ub.u.dk providing detils, nd we will remove ccess to the work immeditely nd investigte your clim. Downloded from vbn.u.dk on: oktober 01, 2018

2 previous simultion results. The first nd the lst bits in the dropped chnnel hve slightly higher power level thn others due to the pttern effect in SOA. The mesured signl-to-noise rtios (SNR) re 11.4 db nd 10.2 db for dropped chnnel nd remined chnnel, respectively. Due to the limit of experimentl conditions, the dding function ws not demonstrted in this experiment. However, it could be found tht the vcnt time slots on the remined chnnel re clen enough for dding new chnnel by using pssive coupler nd n pproprite time dely. Further simultions (not shown) suggest tht the proposed OADM function could operte t higher bit rtes, which is depended on the performnce of the SOA, especilly the crrier recovery time. On the whole, FWM will not limit the working speed of the module, since it is dominted by ultr-fst crrier dynmics. But the slow crrier recovery time is n obstcle in the XGM process. Fortuntely, severl opertionl prmeters cn be djusted to reduce the crrier recovery time, such s incresing the injection current, incresing the opticl power or using ssist light. Though fine-tuning these prmeters, this module is ble to work t significntly higher bit rtes. 4. CONCLUSIONS We hve proposed simple nd compct OADM configurtion by using only single SOA. FWM nd XGM effects in SOA re employed to generte dropping nd clering chnnel. Good performnce is shown by both simultion nd experiment t 10 Gbit/s. In ddition, the module cn be scled to higher bit rtes by utilizing better device or optimizing some prmeters. ACKNOWLEDGMENTS This work ws supported in prt by the Funds for Interntionl Coopertion Foundtion of Guizhou Province of Chin under Grnt No. (2009) , specil fund for technology nd eduction tlents of Guizhou Province of Chin under Grnt No. (2009) 98, nd the Funds for import of tlents of Guizhou university Grnt No. (2008) 010. REFERENCES 1. C. Schubert, C. Schmidt, S. Ferber, R. Ludwig, nd H.G. Weber, Error-free ll-opticl dd-drop multiplexing t 160 Gbit/s, Electron Lett 39 (2003), S. Diez, R. Ludwig, nd H.G. Weber, Gin-trnsprent SOA-switch for high-bit rte OTDM dd/drop multiplexing, IEEE Photon Technol Lett 11 (1999), A.M. de Melo, S. Rndel, nd K. Petermnn, Mch-Zehnder interferometer-bsed high-speed OTDM dd-drop multiplexing, J Lightwve Technol 25 (2007), J. Li, B.-E. Olsson, M. Krlsson, nd P.A. Andrekson, OTDM dddrop multiplexer bsed on XPM-induced wvelength shifting in highly nonliner fiber, J Lightwve Technol 23 (2005), E.J.M. Verdurmen, Y. Zho, E. Tngdiongg, J.P. Turkiewicz, et l., Error-free ll-opticl dd-drop multiplexing using HNLF in NOLM t 160 Gbit/s, Electron Lett 41 (2005), P.-M. Gong, J.-T. Hsieh, S.-L. Lee, nd J. Wu, Theoreticl nlysis of wvelength conversion bsed on four-wve mixing in light-holding SOAs, IEEE J Quntum Electron 40 (2004), N.C. Kothri nd D.J. Blumenthl, Influence of gin sturtion, gin symmetry nd pump/probe depletion on wvelength conversion efficiency of FWM in semiconductor opticl mplifiers, IEEE J Quntum Electron 32 (1996), VC 2010 Wiley Periodicls, Inc. A COMPACT UWB BANDPASS FILTER WITH WLAN REJECTION USING A SLOT RING RESONATOR Ming Shen, Tin Tong, Ole K. Jensen, Jn H. Mikkelsen, nd Torben Lrsen Technology Pltforms Section, Deprtment of Electronic Systems, Alborg University, Denmrk; Corresponding uthor: mish@es.u.dk Received 27 November 2009 ABSTRACT: This rticle presents novel ultr-widebnd bndpss filter with controllble notched bnds, compct size, nd relxed fbriction requirements. Its implementtion is bsed on rectngulr slot ring resontor with n embedded S-shped slotline. The behvior of the rectngulr slot ring resontor is chrcterized nd subsequently dopted to build the wide pssbnd. The notched bnd necessry for rejecting wireless locl-re network (WLAN) signls is implemented by the S-shped slotline. A prototype filter is implemented bsed on the proposed structure nd good greement is found between simultions nd mesurements. VC 2010 Wiley Periodicls, Inc. Microwve Opt Technol Lett 52: , 2010; Published online in Wiley InterScience ( DOI /mop Key words: ultr-widebnd; bndpss filter; notched-bnd; slot line; stopbnd ttenution 1. INTRODUCTION In 2002, the Federl Communiction Committee (FCC) uthorized the unlicensed use of the ultr-widebnd (UWB) frequency bnd from 3.1 to 10.6 GHz for indoor nd hnd-held systems [1]. Since then, considerble effort hs been put into the development of devices suitble for UWB pplictions [2]. As one of the essentil components, UWB bndpss filters (BPF) hve ttrcted significnt reserch interest nd vrious pproches to the design of UWB BPFs hve been proposed [3 9]. Bsed on the fct tht the WLAN signls (MMAC HiSWAN: GHz, GHz; ETSI HiperLAN2: GHz, GHz; IEEE : GHz, GHz) re locted within the UWB frequency bnd, s shown in Figure 1, UWB systems should expect interferences originting from ny one of these WLAN signl bnds [2]. To reduce WLAN relted interference problems one option is to introduce stop bnd in the UWB BPF s response t corresponding frequencies. It could be either 5 6 GHz stop bnd for the rejection of ll the WLAN bnds or nrrow stop bnd to reject one of the sub bnds. UWB bndpss filters following this pproch hve previously been reported; In one cse, filter bsed on five shortcircuited stubs hs been proposed, nd embedded open-circuited stubs were used to introduce notched bnd [4]. Another filter combines conventionl bndpss chrcteristic nd negtive permittivity metmteril to estblish n UWB response nd notch [5]. However, these designs hve comprtively lrge sizes. A compct filter using trilyer structures hs the dvntge of miniturized size [6], but it is unsuitble for conventionl double lyer PCBs. Using modified multiple mode resontor fed by interdigitl coupled lines, n UWB BPF hs been built, nd notch bnd ws creted by extending nd folding one of the two rms in the coupled-line section [7]. A filter bsed on stubloded modified stepped impednce resontor nd two identicl interdigitl feed-lines hs lso been proposed [8]. However, usully nrrow strip/slot widths re preferred in the interdigitl coupled lines used in these designs (min. gp width of 0.05 mm in [7]), which require tight control of fbriction tolernces MICROWAVE AND OPTICAL TECHNOLOGY LETTERS / Vol. 52, No. 9, September 2010 DOI /mop

3 re relted to the resonnt frequencies of the resontor [11], which cn be determined by 2ðL 1 þ L 2 Þ¼nk s ; (1) Figure 1 The FCC UWB EIRP msk, nd the WLAN bnds of different stndrds where k s is the slotline wvelength, nd n is the mode number. Using Eq. (1), the first three resonnt frequencies cn be clculted to 4, 8, nd 12 GHz for this design. The simulted S 21 - mgnitudes of the resontor for three different vlues of L 3 re shown in Figure 2(b). The first three resonnt modes cn be clerly seen t 4.3, 8, nd 11.7 GHz when L 3 ¼ 0.1 mm, which is in good greement with Eq. (1). As L 3 increses to 2.9 mm (round one-qurter of the microstrip wvelength t 6.85 GHz), Moreover, lthough upper stop bnd (>10.6 GHz) ttenution is importnt for upper bnd interference nd noise suppression, only few UWB BPFs with notched bnd nd stisfctory upper stop bnd performnce hve been reported [7, 9]. This rticle proposes novel ultr-widebnd bndpss filter tht offers compct size, controllble notched bnds, nd relxed fbriction requirements. The topology is bsed on rectngulr slot ring resontor with n S-shped slotline. In this study, the multimode resonnt behvior of the rectngulr slot ring is dopted to chieve the ultr-wide pssbnd. The notched bnd for rejecting WLAN signls is implemented by embedding the S-shped slotline, while mintining the smll circuit size of mm 2. The S-shped slotline plys role of hlf wvelength resontor, so tht trnsmission zero cn be introduced t the resonnt frequency. It is lso shown tht n upper stopbnd ttenution of 28 db cn be esily chieved by connecting two low-pss filters (LPF) t both ends of the proposed UWB BPF. A prototype filter is fbricted to verify the design. Simulted nd mesured results re shown nd comprison with previous work is provided. 2. DESIGN OF THE UWB BPF WITH A NOTCHED BAND Figure 2() shows the proposed rectngulr slot ring resontor for the implementtion of UWB BPFs with notched bnds. It consists of two 50 X microstrip feed lines with open stubs (solid lines) on one metl lyer of two-metl-lyer substrte, nd rectngulr slot ring resontor with n embedded S-shped slotline (white strips) etched on the other metl lyer (shded re). To clerly explin the principles of this coupling structure, the multimode resonnt behvior of the originl rectngulr slot ring resontor without the S-shped slotline is studied first. The study is conducted by simultion using the Agilent ADS Momentum simultor with the substrte RT/Duriod 6010 hving reltive dielectric constnt of e r ¼ 10.2, loss tngent of tn d ¼ nd thickness of t ¼ mm. The originl resontor is shown in the embedded figure in Figure 2(b). The equivlent circuit of the originl resontor is shown in Figure 2(c), where Z 0s nd h s re the chrcteristic impednce nd hlf of the electricl length of the slot ring, respectively. Z 0mo nd h mo re the chrcteristic impednce nd electricl length of the microstrip open stub, respectively. C oc represents the prsitic cpcitnce t the end of the open stub, nd N is the turns rtio of the trnsformer modeling the coupling between the microstrip nd the slotline. The width of the slotline is set to 0.9 mm to hve chrcteristic impednce of round 100 X for impednce mtching, nd the width of the open stubs is set reltively wider, to 1.8 mm, for bndwidth improvement [10]. L 1 nd L 2 re set to 6.9 nd 8.5 mm, respectively. They Figure 2 () Schemtic of the proposed rectngulr slot ring resontor, (b) simulted S21-mgnitudes versus frequency of the resontor without S-shped slotline, nd (c) the equivlent circuit for the resontor without S-shped slotline. The prmeters for this figure re: L 1 ¼ 6.9 mm, L 2 ¼ 8.5 mm, W 1 ¼1.8 mm, W 2 ¼ 0.9 mm nd vried L 3. [Color figure cn be viewed in the online issue, which is vilble t wiley.com] DOI /mop MICROWAVE AND OPTICAL TECHNOLOGY LETTERS / Vol. 52, No. 9, September

4 Figure 4 Simulted S21-mgnitudes versus frequency of the UWB BPF without the S shped slotline (without notch), with the S shped slotline (with notch) nd with the S shped slotline nd LPFs. [Color figure cn be viewed in the online issue, which is vilble t Figure 3 () The equivlent circuit for the proposed resontor in the UWB pssbnd, (b) simulted rejection bnd versus frequency with vried L 5 (L 4 ¼ 1.5 mm) nd (c) simulted rejection bndwidth versus frequency with vried L 5 nd L 4. The prmeters for this figure re: W 1 ¼ 1.8 mm, W 2 ¼ 0.9 mm, W 3 ¼ 0.3 mm, W 4 ¼ 1 mm, L 1 ¼ 6.9 mm, L 2 ¼ 8.5 mm, L 3 ¼ 2.9 mm. [Color figure cn be viewed in the online issue, which is vilble t the microstrip open stub cn be pproximted s short circuit with neglectble end effects, nd the turns rtio N is close to 1. As result the significnce of the resonnces is reduced, nd 3-dB ultr-wide pssbnd from 2.8 to 10.9 GHz is chieved. An extr slotline is further integrted into the slot ring resontor s shown in Figure 2() to introduce notch into the pss bnd of the UWB BPF. The extr slotline is implemented s n S shpe for esily embedding into the originl circuit, while mintining the originl circuit size. The S-shped slot line plys role of hlf wvelength resontor, nd it introduces trnsmission zeros t the resonnt frequencies. A prllel resonnt circuit s shown in Figure 3() is used to model the behvior of the circuit including the S-shped slotline by simplifying the originl microstrip fed slot ring resontor to 50 X trnsmission line within the UWB pss bnd. In the circuit, L r, C r, nd R r cn be extrcted from simultions [12]. By modifying the structurl prmeters of the S-shped slotline, the loction nd bndwidth of the notch cn be controlled, which cn be modeled by vrying L r, C r, nd R r. Figure 3(b) shows the simulted S 21 -mgnitudes of the proposed structure for fixed L 4 ¼ Figure 5 Schemtic of the proposed UWB BPF (W 1 ¼ 1.8 mm, W 2 ¼ 0.9 mm, W 3 ¼ 0.3 mm, W 4 ¼ 1.0 mm, L 1 ¼ 6.9 mm, L 2 ¼ 8.5 mm, L 3 ¼ 2.9 mm, L 4 ¼ 1.45 mm, L 5 ¼ 1.4 mm). Only one of the LPFs is shown in detils MICROWAVE AND OPTICAL TECHNOLOGY LETTERS / Vol. 52, No. 9, September 2010 DOI /mop

5 1.5 mm nd three different vlues of L5. It cn be seen tht the notched bnd is moved to lower frequencies when the S-shped slotline is extended by incresing L5. Simulted S21-mgnitudes with vried L4 nd L5 re shown in Figure 3(c). It cn be seen tht the 3-dB notched bndwidth cn be djusted from 250 MHz (L5 ¼ 1.4 mm, L4 ¼ 1.5 mm) to 1 GHz (L5 ¼ 1.7 mm, L4 ¼ 0.4 mm) by modifying L5 nd L4. This is minly due to the vrying of the cpcitnce Cr by chnging the distnce between the bended slot lines. By doing so, the notched bnd cn be djusted to reject interfering signls of one (for exmple GHz) or ll WLAN bnds mentioned in section 1. In this study, L4 nd L5 re set s 1.45 nd 1.4 mm, respectively, to build notched bnd t round the centrl frequency of GHz, i.e., GHz s demonstrtion. To void the undesired impct of the second notch t GHz on the UWB pss bnd, stepped slotlines with width of 0.3 (W3) nd 1 mm (W4) re used to move the second notch to 11.7 GHz (see Fig. 4). The simulted S21-mgnitudes of the UWB BPF with nd without notched bnd re shown in Figure 4. From Figure 4 it is pprent tht the UWB BPF shows limited ttenution in the upper stopbnd. To show tht this drwbck cn be esily eliminted, two identicl low-pss filters bsed on cpcitively loded trnsmission lines re connected t two ends of the UWB BPF to improve the upper stopbnd ttenution. The complete lyout of the designed UWB BPF is shown in Figure 5. The simulted S21-mgnitude of the UWB BPF with upper stop bnd improvement is shown in Figure 4. It Figure 7 Simulted S21-mgnitudes with two different dielectric constnts, nd the mesured S21-mgnitudes versus frequency. [Color figure cn be viewed in the online issue, which is vilble t www. interscience.wiley.com] cn be seen tht the upper stop bnd ttenution is drsticlly improved while the desired UWB BPF response is mintined. 3. EXPERIMENTS AND RESULTS The UWB BPF fbricted using RT/Duriod 6010 substrte hs compct size of 7.8 by 26.7 mm. Both the top nd the bottom lyers of the BPF cn be seen from Figure 6(). The simulted nd mesured mgnitudes of S-prmeters re shown in Figure 6(b). Here n excellent greement is found between simulted nd mesured results. The mesured results show 3-dB frequency bnd of GHz. The insertion loss is 0.75 nd 1.3 db t 3.9 nd 8 GHz, respectively. The return loss is better thn 9 db in both pss bnds of GHz nd GHz. Figure 7 shows the simulted nd mesured S21-mgnitudes in 5 6 GHz, where shrp 3-dB notched bnd with mximl ttenution of 21 db cn be observed in the frequency bnd of GHz. It lso cn be seen tht there is difference of bout 100 MHz between the simulted nd mesured Figure 6 () Fbricted UWB BPF, nd (b) simulted nd mesured mgnitudes of S-prmeters versus frequency of the UWB BPF with notched bnd. [Color figure cn be viewed in the online issue, which is vilble t DOI /mop Figure 8 Simulted nd mesured group delys versus frequency of the UWB BPF. [Color figure cn be viewed in the online issue, which is vilble t MICROWAVE AND OPTICAL TECHNOLOGY LETTERS / Vol. 52, No. 9, September

6 TABLE 1 Items [Unit] [4] [5] [6] Comprison of UWB BPFS with Notched Bnd USB/Atten. [GHz]/[dB] MSSW [mm] NBW [%] MNBR [db] Size [mm 2 ] b [7] 11 26/ < [8] [9] 10 20/ This work 12 20/ c USB, upper stop bnd; MSSW, miniml strip/slot width; MNBR, mximl notched bnd rejection; NBW, notched bnd width. Unknown. b 10 db. c with LPF section. notch frequencies. This is ttributed to the tolernces in the lyout nd dielectric constnt. When the dielectric constnt in the simultion is chnged to 10.6 while using the sme lyout, the simulted S 21 -mgnitude mtches the mesured result very well (see Fig. 7). The simulted nd experimentl group delys re shown in Figure 8. The mesured group dely vries from 0.4 to 0.7 ns, nd 0 to 0.65 ns in the frequency bnd of GHz nd GHz, respectively. It is lso cler tht the ttenution is more thn 28 db in the upper-stopbnd from 12 to 20 GHz. Aprt from the good in-bnd performnce, comprison of physicl size, miniml strip/slot width, upper stop bnd ttenution, 3-dB frctionl notched bndwidth nd mximl notched bnd rejection between this work nd previous work is shown in Tble 1. From this comprison it cn be seen tht this work hs the dvntge of superior upper stopbnd ttenution, while providing rejection of WLAN signl comprble to previous work. This is chieved while mintining relxed fbriction constrints nd compct size. 4. CONCLUSION A compct UWB BPF with notched bnd for rejection of in bnd WLAN signls is presented. The design mkes use of novel rectngulr slot ring resontor structure to implement the required WLAN rejection. The novel rectngulr slot ring resontor consists of rectngulr slot ring nd n S-shped slot line, nd the size of the structure is only mm 2 (i.e k 0.55 k, where k is the guided wvelength of 6.85 GHz). Aprt from the good in-bnd performnce shown by mesurement results of prototype filter, the proposed BPF with LPF sections hs compct size of mm 2, relxed fbriction requirement (0.25 mm minimum strip width) nd superior ttenution (better thn 28 db from 12 to 20 GHz) in the upper stopbnd compred with previous work. ACKNOWLEDGMENT This work is supported by the Dnish Reserch Council for Technology nd Production Sciences under the Grnt REFERENCES 1. FCC, Revision of Prt 15 of the Commissions Rules Regrding Ultr-Wide-Bnd Trnsmission System, ET Docket , R. Roovers, D.M.W. Leenerts, J. Bergervoet, K.S. Hrish, R.C.H. vn de Beek, G. vn der Weide, H. Wite, Y. Zhng, S. Aggrwl, nd C. Rzzell, An interference-robust receiver for ultr-widebnd rdio in SiGe BiCMOS technology, IEEE J Solid-Stte Circuits 40 (2005), VC 3. H. Shmn nd J. Hong, A novel ultr-widebnd (UWB) bndpss filter (BPF) with pirs of trnsmission zeroes, IEEE Microwve Wireless Compon Lett 17 (2007), H. Shmn nd J.S. Hong, Ultr-widebnd (UWB) bndpss filter with embedded bnd notch structures, IEEE Microwve Wireless Compon Lett 17 (2007), A. Ali nd Z. Hu, Metmteril resontor bsed wve propgtion notch for ultrwidebnd filter pplictions, IEEE Antenns Wireless Propg Lett 7 (2008), P.-Y. Hsio nd R.-M. Weng, A compct ultr-widebnd bndpss filter with WLAN notch bnd, Microwve Opt Technol Lett 51 (2009), S. Wong nd L. Zhu, Implementtion of compct UWB bndpss filter with notch-bnd, IEEE Microwve Wireless Compon Lett 18 (2008), S.-S. Go, S.-Q. Xio, nd B.-Z. Wng, Ultrwidebnd bndpss filter with controllble notched bnd, Microwve Opt Technol Lett 51 (2009), M.-H. Weng, H. Kun, W.-L. Chen, C.-S. Ye, nd Y.-K. Su, Design of stopbnd-improved UWB filter using pir of shunt nd embedded open stubs, Microwve Opt Technol Lett 51 (2009), K. Gupt, R. Grg, I. Bhl, nd P. Bhrti, Microstrip lines nd slotlines, Artech House Norwood, Msschusetts, C. Ho, L. Fn, nd K. Chng, Slotline nnulr ring elements nd their pplictions to resontor, filter nd coupler design, IEEE Trns Microwve Theory Tech 41 (1993), J. Hong nd B. Krympudi, A generl circuit model for defected ground structures in plnr trnsmission lines, IEEE Microwve Wireless Compon Lett 15 (2005), Wiley Periodicls, Inc. ADDING MICROSTRIP LINE AT THE BOTTOM OF PCB FOR ENHANCING ANTENNA BANDWIDTH B.-G. Cho, K.-M. Lee, nd Y.-S. Kim Deprtment of Rdio Sciences nd Engineering, The Grdute School, Kore University, Kore; Corresponding uthor: bkcho264@kore.c.kr Received 4 December 2009 ABSTRACT: In this rticle, dded microstrip line t the bottom re of printed circuit bord (PCB) is proposed for improving the bndwidth of GSM900, DCS1800, nd PCS1900. By printing the microstrip line t the bottom re of PCB, frequency bndwidth of slim-type cellulr phone which hs low-profile monopole ntenn is improved. Dimension of the microstrip line is 45 mm 9 mm. The width nd length of the microstrip line is modified for good bndwidth. The mesured return loss of the ntenn is better thn 7.3 db for low nd high bnd. Mesured pek gins of the proposed ntenn present 3.41, 5.48, nd 5.95 dbi in ech bnd, respectively. Detils of the ntenn design re described. Its performnces re lso presented. VC 2010 Wiley Periodicls, Inc. Microwve Opt Technol Lett 52: , 2010; Published online in Wiley InterScience ( wiley.com). DOI /mop Key words: monopole ntenn; mobile ntenn 1. INTRODUCTION A cellulr phone is developed to hve smll volume for good design nd to include lot of prts for multifunctions. This mkes the llocted volume of ntenn smll. A cellulr service provider enforces specifictions of ntenn performnce to sve cost nd reduce the customer s complins for bd connection in wek 1984 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS / Vol. 52, No. 9, September 2010 DOI /mop