Tunable Active Dual-Band Bandpass Filter Design Using MMIC Technology

Transcription

1 Interntionl Journl of Engineering & Technology IJET-IJENS Vol: 11 No: 1 11 Tunle Active Dul-Bnd Bndpss Filter Design Using MMIC Technology A. Alhyri 1, A.Hizdeh, M. Dousti 3 1 Islmic Azd University Broujerd Brnch, Broujerd Irn Islmic Azd University- Hshtgerd Brnch, Krj, Irn 3 Dept. of Electricl Engineering, Science nd Reserch rnch, Islmic Azd University, Tehrn, Irn Astrct The inductor-less designing of monolithic tunle ctive dul-nd ndpss filter is presented in this study. Bising voltges signify min role. They cn control the center frequency nd qulity fctor. Using four ising voltges nd cscding two similr filters leds to dul-nd ndpss filter. By keeping the gin constnt, the center frequency shift is MHz. Regrdless constnt gin, qulity fctor cn rnge from 6 to 18 t the center frequency. The proposed filter is designed using MMIC technology with the center frequency of GHz nd the power consumption of 4 mw. THE NEW APPROACH TO DESIGN BANDPASS FILTER The ctive filter consists of two lowpss filters in negtive feedck loop construction (fig.1.). The high frequency signls re trpped y lowpss filter1 (LPF1) nd these low frequency signls re fed ck y lowpss filter (LPF). Therefore, in some frequency rnge, the response will e like ndpss filter [4]. The resulted ndpss filter is shown in fig.1.. Index Term-- Monolithic integrted circuit technology (MMIC), lowpss filter (LPF), nd dul-nd ndpss filter. TRODUCTION Vrious pplictions of microwve frequencies hve found specil ttention in different criteri. In recent yers, in ddition to design in low frequency domin, designing the circuit nd high performnce equipments t microwve frequencies hs ecome possile. Amplifiers, oscilltors, nd mixers which their designs re sed on ctive nd pssive elements re some exmples. On the other hnd, wireless networks, which included dt communictions, re developing in the frequency rnge from MHz to 6GHz. Since, most of the electronic systems del with high frequency, frequency controlling is the min ide to use these systems. The well- known pssive elements re idel inductors tht do not generte noise; however in prctice their prsitic coil resistnce cuses noise. Inductor- less circuits cn relize low-size chips. In fct they provide lrge svings in re nd hve the dded dvntges of eing widend. To this end, we proposed inductor -less design in our work [1],[]. The new pproch in this study is the design of ndpss filter using two lowpss ones in negtive feedck loop. Cscding two similr ndpss filters leded to dulnd ndpss one. Four DC voltges re used to is vrctor diode in such wy tht the center frequency nd qulity fctor will e controlled using these voltges [3]. Fig. 1. ) digrm of ndpss filter using two lowpss filters ) resulted ndpss filter Assuming the trnsfer functions of filters 1 T1 (s) nd T (s) 1 s1 1 s, the overll trnsfer function, T(s), is defined s elow : H T(s) s s (1) Center frequency,, qulity fctor,, nd constnt vlue, H, re defined s elow : IJET-IJENS Ferury 11 IJENS

2 db(s(,1)) Interntionl Journl of Engineering & Technology IJET-IJENS Vol: 11 No: , () 1 And 1 H (3) 1 The mplifier gin cn e used insted of T 1 nd T : A A( ) (4) 1 j c A nd c will e chnged using cpcitors nd vrious resistors. To chieve tunle filter, we cn use two ising voltges connected to the cpcitors nd resistor. In the next sessions we will explin the steps to design the dul-nd ndpss filter. THE STRUCTURE OF ONE- STAGE BANDPASS FILTER The lowpss filters in negtive feedck loop re relized using p-hemt trnsistors. Fig., shows the filter nd the scttering prmeter S1. As cse for comprison, differentil mplifier with unit gin is used etween two lowpss filters (Fig. 3). Common gte nd common drin structures re used to relize input nd output impednce mtching respectively (Fig.4,). Using this structure gives good input nd output impednce mtching. Eqution () yields the clculted gm = ms. Fig. 3. the circuit of differentil mplifier in ndpss filter gm (Re ly(1,1)) (Im gy(1,1 )) () Fig.. ) the circuit of lowpss filter ) gin prmeter Fig. 4. ) common gte ) common-drin structure for input nd output impednce mtching nd V in Fig. ised the vrctor diode nd the cpcity would chnge due to the pplied voltge. Also these voltges sweep the frequency. shifts the center frequency nd V controls the mplitude in order to keep the gin constnt. Fig. shows the lock digrm of the desired filter nd the input nd output dpttion prmeters re depicted in Fig.6,. The power consumption is 13mW IJET-IJENS Ferury 11 IJENS

3 db(s(,)) db(s(,1)) Interntionl Journl of Engineering & Technology IJET-IJENS Vol: 11 No: 1 13 LPF1. V Differentil mplifier LPF Fig.. The circuit of one-stge ndpss filter Tle.1 notes ising voltges nd qulity fctor for ech center frequency. TABLE.1 vlue of V,,, frequency vrition, nd qulity fctor of One -stge ndpss filter f (GHz) V Fig. 6 ) frequency displcement of 7MHz of one stge filter ) input nd output dpttion prmeters nd frequency displcement IV. TWO-STAGE BANDPASS FILTER To increse the qulity fctor, we connect two similr filters in cscded form. As result of this, the qulity fctor nd gin will improve. Only two vrctor diodes re used in the second stge. Fig.7 depicts the two-stge filter circuit. The power consumption of the filter is 4mW. The ising voltges re listed in tle. II. We demonstrted the frequency displcement in Fig.8, T ABLE II ising voltges, qulity fctor nd frequency vrition of two -stge Bndpss filter f (GHz) V IJET-IJENS Ferury 11 IJENS

4 db(s(,1)) db(s(,1)) db(s(,)) Interntionl Journl of Engineering & Technology IJET-IJENS Vol: 11 No: 1 14 Second stge First stge V Fig. 7. The circuit of two-stge ndpss filter -1 V is devoted to increse the qulity fctor significntly in constnt frequency. It improves the qulity fctor form to 1 (Fig. 9) V. DUAL -BAND TWO STAGE BANDPASS FILETR The filter structure is similr to two-stge ndpss one, ut we used four vrctor diodes nd four ising voltges (, V in first stge nd 1, V 1 in the second stge) in this cse[]. At first we djust the center frequency of filters t 1.7 GHz nd.16 GHz respectively. In oth filters, the gin is 4dB nd the distnce etween two frequencies is 41 MHz (Fig.1) freq= 1.7GHz db(s(,1))=4.14 m freq=.16ghz db(s(,1))=4.49 m Fig. 8. ) input nd output dpttion prmeters ) gin prmeter nd frequency displcement of 68MHz in two- stge ndpss filter Fig. 1. dul- nd ndpss filter IJET-IJENS Ferury 11 IJENS

5 db(s(,1)) db(s(,)) db(s(,1)) db(s(,1)) Interntionl Journl of Engineering & Technology IJET-IJENS Vol: 11 No: 1 1 Agin we use 1 nd in order to sweep the frequency. A two-stge monolithic vrctor-tuned ndpss filter hs tunle insertion gin using FET device which is suitle within this ppliction s it cn hve vrctor-controlled negtive resistnce component[6]. In this work we pply V 1 nd V to mintin constnt gin. The simultion results re shown in Fig.11,. Four ising voltges nd qulity fctors re noted in Tle.III freq= 1.74GHz db(s(,1))=4.31 v1=.8 m m freq= 1.74GHz db(s(,1))=.84 v1= () Fig. 1. qulity fctor increment in the first filter from 7 to 17 VI. CREASG T HE UALITY FACTOR DUAL-BAND BANDPASS FILTER We demonstrted tht V 1 nd V cn control the qulity fctors of first nd second filter respectively. For instnce, in fig.1 we improved the qulity fctor of the first filter form 7 to 17 t 1.74GHz. Also the gin rised 1dB. The frequency shift of MHz is ignored. Fig.13 shows the qulity fctor in the second filter incresed form to 9 t.16ghz. The gin improvement is 7dB nd the frequency shift is 1MHz. The stility of this filter hs een studied y Rollett coefficient (K). This coefficient is lwys greter thn one [7] freq=.17ghz db(s(,1))= v1=-1. m freq=.16ghz db(s(,1))=41.87 v1=-.9 () Fig. 11. ) frequency displcement of dul-nd ndpss filter ) input nd output dpttion prmeters 4 4 m T ABLE III The ising voltges of vrctor diodes, frequency vrition, nd qulity fctors in dul-nd ndpss filter 3 1 f 1 f (GHz) (GHz) 1 V 1 V Fig. 13. qulity fctor increment in the second filter from to 9 VII. STATISTICAL RESULTS The effect of elements vrition on two-stge nd dulnd ndpss filters hs een studied. In this section we simultneously exerted % tolernce on the vlue of 3 elements including resistor, cpcitor, nd trnsistor width in oth two-stge nd dul-nd ndpss filter. These IJET-IJENS Ferury 11 IJENS

6 db(s(,1)) db(s(,)) db(s(,1)) db(s(,)) Interntionl Journl of Engineering & Technology IJET-IJENS Vol: 11 No: 1 16 vritions were completely rndom. Fig.14, shows simultion results of comintion of fifteen different situtions in which the filter is not sensitive S Fig. 1. ) gin ) input nd output dpttion prmeters s result of % tolernce in dul-nd ndpss filter S Fig. 14. ) gin ) input nd output dpttion prmeters s result of % tolernce in two- stge ndpss filter The simultion results of dul-nd ndpss filter re illustrted in fig.1, VIII. CONCLUSIONS We hve presented the design of tunle ctive filter tht does not rely on the use of inductors. The filter structure consists of two ndpss filters. Cscding these filters long with ising voltges leds to dul-nd ndpss filter. Controlling the center frequency nd qulity fctor is investigted nd hs een done using four ising voltges. It is culminted tht the frequency displcement in EDAH technology used in our work is higher thn RFCMOS or BiCMOS s result of identicl voltge vritions on vrctor diodes. The filter hs good stility fctor nd it is not sensitive to element vritions. In future work, we re going to use neurl network to estimte the center frequency nd qulity fctor. REFERENCES [1] M.J.Schindler nd Y.Tjim, A Novel MMIC Active Filter with lumpednd Trnsversl Elements, IEEE Trns. Microwve Theory Tech., Dec.1989,pp [] Km weng Tm,Pedro Viter nd Rui P Mrtins, MMIC Active Filte with Tuned Trnsversl Element, IEEE Trnsctions on circuits nd Systems -My [3] Hideo Suwki nd Tkshi Ohir, A Very Smll MMIC Vrile Filter Bsed on New Active Filter Design Concept, IEEE [4] Roerto Gomez-Grci, Cesr Briso-Rodrigez, Mustgf Mhfoudi nd Josei Alonso, MMIC Tunle Trnsversl Bndpss Active Filter t 9-1 GHz, symposium-munich 3. [] Yu Cheng, chung-yu Wx, Jeng Gong, The Design of -V 9MHz CMOS Bndpss Amplifier, Anlog Integrted Circuits nd Signl Procesing, volume 7, Numer 3, 19-8, DOI:1.131A: [6] Krcoglu, Ulun, Roertson, In D A MMIC Active Bndpss Filte With FET Negtive Resistnce Elements,Microwve Journl, 1July. [7] M. Dousti nd P. Lngri, A Tunle Active Recursive Filter ForCommuniction Systems in SiGe BiCMOS, AICT IEEE conference, Bku IJET-IJENS Ferury 11 IJENS