VNU Journal o f Science, Mathematics - Physics 25 (2009) 185-189 Research, design and fabrication o f a high-power combiner using Wilkinson bridge o f L-band Dang Thi Thanh Thuy' *, Vu Tuan Anh^, Vu Duy Thong^, Bach Gia Duong^ Faculty o f Physics, College o f Science, Vietnam National University Hanoi ’Research Center Electronics and Telecommunication, College o f Technology, VNU D epartment o f Science and Technology, Ministry o f Defense, Hanoi, Vietnam Received 24 June 2009 Abstract In this paper, we are dealing with a L-band power combiner method using the Wilkinson bridge This is a modem power combination technique in the microwave technology The design and simuỉink o f the basic power moduls and Wilkinson bridge were performed using the ADS soflware We have researched, designed and fabricated the power combination from the basic 200W moduls The experimental results showed that power combination method using the Wilkinson bridge may be applicable in the L-band transmission Keyword: Microware, Wilkinson, power combination Ỉ Introductiun The assem ble o f the L-band high-pow er amplifier is usually difficult, therefore the search for the pow er com bination m etho ds is important The pow er com bination m ethod using the Wilkinson bridge IS one o f m eth ods that have been taken into account W e have studied and aplied this method ibr co m bin in g po w er from the basic modules W ilkinson p ow er divider was proposed by E J Wilkinson [ 1], as a m e th o d o f distributing pow er to attain equiphase and equiam plitude condition Theories The W ilkinson p o w e r divider can use as com biner or divider It is a simple pow er divider cannot simultaneously have all the properties o f lossless, reciprocal, and matched Hence, the W ilkinson power divider w as developed Here, an isolation resistor is placed betw een the output ports to help achieve the properties D issipation o f energy occurs only in isolation resistor w hen signal enters the network from any o u u t port H ow ever, it should not affect W ilkinson netw ork efficiency Besides, this isolation resistor provides perfect isolation to protect output ports at the operating frequency Correcsponding author E-mail: dangthuyhn@gmail.com 185 186 D T Thuy ei cil / VNU Journal o f Science Mathematics - Physics 25 (2009) ỈS5-Ỉ89 Generallv, W ilkinson p o w e r d iv id er can have anv nu m ber o f output ports A basic three por W ilkinson pow er divider o f p o rt characteristic impedance Zo is schem atically show n in Figure I Fig Schematic diagram of aWilkinson power divider [1] This IS a such netw ork that the lossless and resistive T-junction p ow er dividers have no isolation b etw e en the ou u ts o f p ort an d p ort 3, and the lo s s le s s d iv id er IS n ot m a tch ed at all p orts, and the resistive pow er divider is lossy T h e W ilkinson pow er divider has all ports m atch ed and has isolation between output ports, b u t is lossy [1] T he W ilkinson pow er divider is a 3-port device with a scattering matrix of: - J - j l ề ( 1) Note this device IS m atched at port (S n = 0), and we find that m agnitude o f colum n is: S oSp i l ’ S 21 ' 0s, “ (2) Ihus, ju s l like the lossless d iv id er the incident pow er on port IS evenly and cííicicnily divided between the outputs o f port and port But now look closer at the scattering matrix Wc also note that the ports and o f this d ev ice are matched It looks a lot like a lossless 3dB divider, only with an additional resistor b etw ee n p o rts and Design W ilkinson p o w e r d ivid er We simulate the W ilk inso n brigdc by ADS solfware (figure 2a), the frequency o f transmission signal is 1030 M Hz, w e retrieve the S-matrix param eter m agnitudes depicted in Figure 2b, 2c The 1030 M H z frequency w as studied because this frequency will application in our the next rescach for design and fabrication o f a tran sm itter system for the phase identification code D T Thuy el al / \'NIJ Journal o f Science, Maihemaiics - Physics 25 (2009) Ỉ 85-189 r— n mi ĨH Ũ TU WTo:_AO.S Su0st='MSucr Sut»t=*MSubr W=1 53303 rm {Q w = 96 3 rrm L=40 3207rTĩn{ạ n le fT s s Him =2 87 TifrrC z= 500hm L=10frm{-t) 1 T n-i - í TL1 Subsr^WSuCl* 0— V ^^29632XrTm Ĩwm1 L=lQfmi{-t} 2=50 Ohrr R1 ftiiOOOfvn SuDsp'fcejcr WM53rm W = ittti Subst^-MSdbt' ‘.I?i T112 Sutet^^-MSubl' V^lS33C3fTTTi{1} W=r2 96 3 m L 415207fiTn(ị L=10rrm{-t} 'A \ Ĩ1 I Terr T«rrM ^*ấI»=3 z=500m (a)Tlie Wilkinson by ADS solfware m2 ■freq=1 030GHz m1 ;freq=1 030GHz ỜB(S(2.1))=-3 011 ,dB(S(2,2))=-39 305 Ũ ml -1 - COfN*- -20- é ể i •30- •CT5T5 t y -40-50 • 02 04 06 10 12 14 16 18 freq GHz freq, GHz (b)S parameter mamiitude (c) s parameter magnitude FMg T h e s e m u lin k results Base on W ilkinson brigde niclhods, wc propose a com bination m e th o d s from the medium power mociul and the small pow er modul (Figure 3) 2()()W Fig The power combining use Wilkinson brigde Experim ents result We have designed and fabricated the 200W amplifier m od ules from the smaller ones The basic modules w ere designed by using the microtrip technology [4], w hich are small and portable (figure 4a) After simulink modelling, the W ilkinson bridge was designed usin g the modern accurate circuit imprint technology [2,3](figure 4b) 88 D T Thỉiy et a! / Ỉ'NU Journal o f Science, Mathematics - PhysiCs 25 (2009} ỉiS5~ỈS9 (a) (b) Fig T h e 0 W p o w e r am p lifie r (a) T h e W ilk in so n bridize (b) From the basic amplifier m o d u ls and Wilkinson bridge divider we have fabricated the hiuh-pow cr combination circuit as illustrated in figures hig i he integration 0Í the Ircquency combinanon circuit The amplifier m odules w ere carefully chccked to assure the com patibility so that the risk o f malfuction after the integration is minimal Obscr\Mim the working o f the 200W am p lin cr by the network analyzer (Rolde &L S ch w arz ESPi, K llz -3 G llz, lest receiver), we r c \c a le d tliat the band width was quite wide and the am plify ing coefficient has achieved the high value within tlic trequencN ranee 90 5M H z-1060M lỈ7 (F'ig 6a)[4] The signal at 1030 M H z was inputcd iiilo tlie am plifying module and observed on the spcctrum analvzcr (Advanlcsl R3765CG (300 K lIz-3.8 G Hz)), the result showed that at 1030 M llz the an iplifying cocfUcicnt readied high value, tlie input am plitude was set a t-lO d B and the output one w as above 16dB The adjustment o f current regim e m av increase the amplifying coefficient even more We have also investigated tlie S il factor o f the power divider Wilkinson on network a n a ly /x r, the result was relatively similar to that o f the simulink model Aftcrthal we have measured the characteristics o f the pow er com biner using the W inkinson bridge The input am plitude from the g enerator was set at -lOdB and was directed to the am plifier module before the divider This pow er a m p lifier was com posed from the three m odules having the pow er IW, 45W and 200W The output am p litu d e reached 29dB The signal was then transm itted to the divider, the two outputs also reached 6dB and were synchronized The outputs w ere inputed to the 200W amplifier modules These m o d u les were set to work in the AB regim e with am plifying D T Thuy et al / \ ’NU Journal o f Science, Mathematics - Physics 25 (2009) 185-189 189 coefficient G =27 aiid the output am plitude reached 53dB A fterthat w e utilized the Wilkinson bridge to com bine the tw o output signals The final amplitude was 56dB w h e n m easured with the Watt Meter Model -S ^ : : , ', ! j ' * \ 11, 'C T Í0 C (a) :0;C 5i ; (b) Fiu (a) T h e f re q u en cy characteristics; (b) S p e c t r u m at M H z C onclusion \Vc have designed, successfully fcibricated and tested the p o w e r com bination unit using the Wilkinson bridge, i'he expcrimtMital results demonstrated the efficiency o f this method in manuiacluring the larger m odules from the smaller ones and w e anticipate to applicate this method for ilie o i il pn t p o w e r in n e a r f u t u r e Ackncm n lc g m cn t riie results o f this work belong to the research project K C.01.12/06-10 from State Prouranis on Scientific Research o f Vietnam One o f these au th ors would like to thank the support tVom llie research proJcct Ọ T 09-13, V ietnam National University, Hanoi References 11| !)aviij M l*o/ar, X iicrow ave E ngineering 2"*^ E-^dition John Wilcv & Sons, inc., New york United Slate o f Amcrica, [2] '.i Mchran C'AI) ofM icroslrip i'iltcrs considering dispersion loss aiid discontinuity cITccls, IE E E Trans S n J - Mar ;1979) 239 |3 ] Mchran, A method o f analysis and dcsiiin o f microslrip directional couplers considering dispersion and discontinuity ciiocls, Proc oj ih e 1970 in fo rm a tio n a l Sym posiu m on C o m p u ter-A id ed D esig n o f the E lectrics f o r Space A pplication Bol 0i;na (Italy) ( 1979) 7A [4] 3ang I hi Thanh Thuy, !*ham Van Thanh, Nguyen Anh Tuan, Bach Gia Duong, Research, Design And Fabrication O f 1he 45W And I hc 2{)()W, I,-Band Power Amplifier Using The Modem Microstrip Technology For Application In The National Sovereignly Identification Coding System, J o u rn a l o f Science, VN U , Vol XXI!, N o 2AP (2008) 210 ... 0i;na (Italy) ( 1979) 7A [4] 3ang I hi Thanh Thuy, !*ham Van Thanh, Nguyen Anh Tuan, Bach Gia Duong, Research, Design And Fabrication O f 1he 45W And I hc 2{)()W, I,-Band Power Amplifier Using. .. port and port But now look closer at the scattering matrix Wc also note that the ports and o f this d ev ice are matched It looks a lot like a lossless 3dB divider, only with an additional resistor... unit using the Wilkinson bridge, i'he expcrimtMital results demonstrated the efficiency o f this method in manuiacluring the larger m odules from the smaller ones and w e anticipate to applicate