A Highly Linear LNA with Noise Cancellation for GHz UWB Receivers

Transcription

1 A Hihly inear NA with Noie Cancellation for GHz UWB Receiver R. Mirzalou*, A. Nabavi**, and G. Darvih* Abtract: Thi paper preent a new ultra-wideband NA which employ the complementary derivative uperpoition method in noie cancellation tructure. A pmo tranitor in weak inverion reion i utilized for imultaneou econd- and third-order ditortion cancellation. ource-deeneration technique and two hunt inductor are added to improve the performance at hih frequencie. The deeneration inductor reonate at f T / and realize a new input matchin technique that widen the bandwidth with decreain it quality factor and input capacitance, while flatten the input reitance and alo improve the db Compreion Point. The hunt inductor reonate at the center frequency of the band and improve the effective bandwidth of noie/ditortion cancellation technique. Thi NA ha been deined in a 0.8 μm CMO proce and conume 8. ma from.8 V power upply. The chip area i 0.55 mm. The noie fiure and voltae ain are db and db, repectively. i lower than -.5 db over GHz and IIP i 7.5 dbm, IIP i dbm. Thi technique improve IIP more than 9 db. Keyword: ultra-wideband (UWB, low-noie amplifier (NA, noie cancellation, ditortion cancellation, input matchin. Introduction Ultra wideband communication i of reat interet due to an endle demand for hih data rate portable device. The lare.-0. GHz bandwidth available for UWB tandard make a ood candidate for hih reolution poitionin ytem. ince a lare WiFi interferer in the middle of the UWB band (5 GHz exit, the band of operation i uually divided into lower-band ( GHz and upper-band ( GHz []. ince the lare interferer make it challenin to utilize the whole bandwidth in UWB ytem, deinin an NA a the firt block of each receiver for the whole bandwidth doen t eem to be the bet idea. imitin the dein to only upper band of UWB can relax the challene for 50Ω input matchin over the bandwidth, and may provide better noie and linearity performance while the power conumption i minimized. A the CMO technoloy cale down, the noie and the bandwidth of the NA can be improved []. However, the linearity will derade due to nonlinear Iranian Journal of Electrical & Electronic Enineerin, 0. Paper firt received 4 Dec. 0 and in revied form 8 Jan. 0. * The Author are with Department of Electrical Enineerin, cience and Reearch Branch, Ilamic Azad Univerity, Tehran, Iran. r.mirzalou@rbiau.ac.ir, darvih_h@rbiau.ac.ir. ** The Author i with Tarbiat Modare Univerity, Microelectronic aboratory, Tehran, Iran. abdoln@modare.ac.ir. output conductance, mobility deradation, velocity aturation, and poly-ate depletion. Therefore, uin a linearization technique i inevitable in NA circuit at hih data rate [], while noie cancellation cheme could be incorporated to achieve lower noie fiure. The noie cancellation technique in [, 4, 5] improve the NA noie fiure by cancellin the channel thermal noie of CG tranitor throuh addin Ctae band ubtractin the two output, while their IIP i lower than 0 dbm. Often for linearity improvement in UWB NA, the derivative uperpoition and potditortion cancellation technique employ additional tranitor nonlinearity [,, 7] or an active nonlinear reitor [, 8] to cancel out the nonlinearity term of the main device, while the additional tranitor derade the noie fiure and hrink the bandwidth. Alo, input matchin i deraded in derivative uperpoition method. A broadband NA topoloy i propoed in [] for imultaneou noie and ditortion cancellation which i uitable for improvin both noie fiure and linearity while the input matchin i deraded. In thi paper, a two-tae UWB noie and ditortion cancellation NA i introduced with new input matchin network. In the propoed NA a pmo tranitor in C-tae i employed for imultaneou econd- and third-order ditortion cancellation, imilar to complementary derivative uperpoition technique in C and CG topoloie. In addition, two additional 4 Iranian Journal of Electrical & Electronic Enineerin, Vol. 8, No., ep. 0

2 inductor are ued, which extend the effective bandwidth for input matchin and noie/ditortion cancellation. The reminder of thi paper i oranized a follow. ection preent the new input matchin technique which i appropriate for noie cancellation topoloie. ection decribe the noie cancellation criteria and the method for olvin the problem of paraitic in hih frequency. ection 4 ive an analytical decription of the ain and ditortion cancellation by uin frequency dependent analyi. Finally, ection 5 preent the imulation reult and ection conclude the paper. UWB Input Matchin Analyi Two typical topoloie for NA input matchin are preented in Fi. (a and Fi. (b, namely inductor deeneration common-ource NA (C-NA and common-ate NA (CG-NA, repectively. In Table, in (ω, the input impedance een from R, and the input matchin network quality factor, Q match, are lited. For implicity all paraitic and body effect, except ate-to-ource paraitic capacitor, are inored. Coniderin the invere relationhip between Q match and bandwidth, the relatively hih Q match of ordinary C-NA lead to impractical UWB matchin requirement and maller NF compared to that of CG- NA [8]. In CG-NA the parallel reonant network reult in low Q match which i proportional to C. Thi capacitor decreae a technoloy cale, leadin to wider bandwidth. The CG-NA ha alo better linearity and lower power conumption [8, 9]. A new input matchin technique for noie cancellation topoloie i propoed in Fi. (c. Thi technique employ the propertie of C-NA and CG- NA to expand the bandwidth of input matchin. In thi topoloy, in reonate in center frequency of band, reonatin out paraitic capacitor. For proper cancellation of paraitic capacitor, the inductor new reonate in the half of tranit frequency (f T /. Hence, C decreae with the frequency dependent factor A (a defined in Table, which lead to lower capacitance and better input matchin. The calculated Q match in Table i low enouh for UWB application. For example, C +C p =0. pf and C /A=0.4 pf yield Q match (f = 8 GHz = 0. and BW = GHz (all parameter like C, C p, and etc. defined in Fi. (c. For ordinary noie cancellation and NA input matchin dein, R =/ m but in new technique, R =/ m ( m new /C +R(ω. Coniderin thi equation, the required m i reduced. Therefore, the mean-quared channel thermal noie current, which i iven by Eq. ( and the bia current, are decreaed. With low bia current, the load reitor can be larer, which in turn compenate the ain deradation due to m decrement in propoed NA. γ ind = 4kTγ d 0Δ f = 4kT m Δ f ( α R in =/ m ( m new /C +R(ω i the implified equation for input reitance. A frequency increae, m i deraded and hence / m acend. R(ω i a decreain function of frequency and hence it compenate the bad effect of hiher frequency on m. V in R in (a C V b M V in R V b in (b C (c Fi. (a Typical inductor deeneration common-ource NA, (b Typical common-ate NA, (c Noie cancellation NA with new input matchin technique. M Table C-NA and CG- NA veru noie cancellation NA with new input matchin technique Topoloy in (ω een from R Q match m C-NA + jω + C jωc ωc R CG- NA Noie cancellation NA with new input matchin technique jω m jωc mnew in ( + jω + jω( C + C C jωc m p ω ωc R C ( + + C Cp A R A, > Mirzalou et al: A Hihly inear NA with Noie Cancellation for GHz UWB Receiver 5

3 F M γ 4KT m = α (5 R ( F M γ 4KT m = α ( R ( Fi. Complete NA chematic. UWB Noie Cancellation Analyi Noie cancellation in broadband NA i an effective technique to improve the NF [4,, 5, 0].The complete chematic of the propoed NA, with additional and new inductor, i depicted in Fi. which i imilar to that in [, 5]. Accurate noie analyi at hih frequency require takin into account the paraitic capacitance at variou node. The power pectral denity of output noie voltae due to R i: m + mro R ( =4KT + m new C + m + + ro R + X ( m m X ( where N = new +(/C + m new /C, =R +, X =(/C X in N, =R +(/C, =R (/C +, T = (/ m (r o /( + N and alo refer to Fi. for definition of paraitic capacitor, C X. The noie factor i the noie contributed by the element normalized to the noie contributed by R, F=V n,out/ R (. By inorin r o, and coniderin only thermal noie of reitor and channel thermal noie current of MOFET, we have: 4KT m R F = R ( F ( R γ T M = 4KT m α X m m- ( X new C + m + R ( ( ( (4 where the noie parameter in MOFET i γ, α= m / d0 and d0 m + mb [, ]. The effect of the CG tranitor M 4 and load reitor on the noie and frequency repone i nelected [9]. The noie factor of circuit i ummarized by F=+F R +F M +F M +F M. At frequencie well below f T, the noie factor of NA i revealed in Eq. (7, coniderin only thermal noie of reitor and channel thermal noie current of MOFET. m R F= (7 R R ( R R in Av γ mnew ( m( ( Rm-( R C m + m + R +R m α + mr + ro - - R R R R A ( in v R r R = and + o m new in + m r o c + ( ( m r o v m + m r A = - R + o R (8 The Noie Fiure contour are plotted by varyin m and m in Fi. 4, uin Eq. (7.The dah line tand for 8 ma contant current conumption of M and M, aumin 0. V for overdrive voltae. Intercept point of dah line and NF contour repreent the optimum bia point with minimum current conumption for a iven NF. Fi. Common-ate chematic for ditortion and noie analyi. Iranian Journal of Electrical & Electronic Enineerin, Vol. 8, No., ep. 0

4 m m Fi. 4 NF contour with different m, m at m =0 ma/v, C =80 ff, new =0 ph, R =00 Ω, m r o =54, γ/α=.8/0.78 M ' noie contribution (% x % of total noie contribution without % of total noie contribution with Fi. 5 imulated noie contribution of M with and without. The optimized value for noie cancellation i not equal to m R = m (R m new /C due to frequency dependent nature of and in in drain and ource of M, a hown in Fi.. Paraitic capacitor C X, C /A, and C at hih frequency caue the impedance to roll off, ivin rie to partial noie cancellation. By uin inductor in parallel with R (ee dah line in Fi., paraitic capacitor are compenated by in and the hunt inductor. Thu, the effective bandwidth of noie cancellation i extended. Up to thi point the ize and bia of M, M, and M with the value of R,, and in are choen. Thee value determine the effect of noie cancellation and hence the Noie Fiure of thi NA. To diplay the effectivene of thi noie cancellin technique, inductor in and are determined uch that they reonate with capacitor C X, C, and C at the center frequency of band, while new i nelected. The percentae of M channel thermal noie current contributed to total output noie i imulated and compared to that of noie cancellin cae with and without, a hown in Fi. 5. Clearly, addin inificantly decreae the noie contribution of M channel thermal noie current. With thi technique, Noie Fiure, IIP, and voltae ain are improved. The effectivene of addin thi inductor in NF improvement i hown in Fi. 5. The importance of thi inductor and it value in IIP and voltae ain will be dicued in the next ection. 4 UWB Ditortion Cancellation and Gain Analyi The ditortion of the NA output voltae in Fi. i caued by the nonlinear drain current of C and CG tranitor, coniderin reitor R and R linear. The nonlinear tranconductance, m and the nonlinear drain conductance, d lead to nonlinear drain current. The ditortion due to d i neliible when mall hunt reitor i ued []. The nonlinear mall inal drain current i expreed by power erie a m m i d = m v + v + v + (9!! For ditortion analyi, we employ the chematic of CG-tae hown in Fi.. A decribed in previou ection, C P and C X are the paraitic capacitor. C i the input couplin capacitor. The equivalent input impedance of M i alo modeled by the RC network of C, new, and m new /C. To examine the frequency dependent ditortion analyi, we aume that C P and C X account for the bandwidth limitin capacitance and employ Volterra erie for the CGtae. To reduce the complexity, the linearity analyi will be limited up to the third-order and the memoryle Taylor erie applied to C-tae []. By denotin: VX = A( ov + A(, ov + A(,, o V (0 Volterra erie kernel are derived by olvin ome KC, where X =(/C X in ( new +(/C + m new / C, =R +(/C, and =R (/C P ( +/C, The econd-order interaction operator i A( A (,. The Volterra erie kernel are derived a: ( + r A( = o H( ( m ro ( ( ( (, + A A A = ( H ( + A(,, = - (,, ro ( (- ( ( ( m A ( A (, + m A A A H ( + + ( H= ( ( ( + r + ( ( + r ( + (4 m o o X ( while the V out i expreed by Eq. (5 with amplified V and V a: m m V out = (- ( m ( -V + (-V + (- V +!! (5 m m ( mv + V + V (!! where ( i the output impedance and alo Mirzalou et al: A Hihly inear NA with Noie Cancellation for GHz UWB Receiver 7

5 ( ( +m r (, V= A A o ( ov + (, ov ( +ro x(, (, ( A (,, V x ( + + ( + + m m V out = (- ( m ( -V + (-V + (- V +!! m m ( mv + V + V (!! o ( (7 Eq. (5 reult in fundamental, econd-order, and third-order V out expreion a follow: V out, fund = (( A( ov m new ( ( c ( + m + (8 ( ( + ( m r + o A( ov m ( ( r + o A (, ov out,ed (( m + new ( + ( c ( + + m + (9 ( + (, o ( o m m + X ( + ( + new ( ( c( + m +! ( ( + mr o A( ov m ( ( +ro! V = - A V A V ( ( -( A (,, ov out,rd (( m new ( + + ( c ( m + V = + (0 -( + + A (,, ov A( ov m m + ( ( ( ( ( ( + x,,,, new C +! m ( ( + r A ( m o ov m + ( ( +ro! A( A (, ov + m + ( ( ( ( new c + m + ( new ( + ( c ( + + m + ( ( + r - ( + m o A( A (, ov (- m ( +ro x ( + ( + ( 4. Gain Analyi C topoloy with ource deeneration inductor ha new a the frequency-dependent feedback element while β=ω new. The feedback path i between the output current and the ate-ource voltae []. For implicity, we examine thee effect with frequency-dependent analyi, uin Eq. (8 that diplay V out,fund a the voltae ain. The m factor are affected by new feedback, decreain the voltae ain. Fi. illutrate the manitude of thi factor by varyin frequency and new. In the left ide of dah line for all frequency and new, the manitude i hiher than With new <0.5 nh criteria, the voltae ain deradation i tolerable. In contrat, m factor increae the ain Fi. The manitude of ((c (+ + factor. when reonate in the band of interet. The huntpeakin inductor,, in erie with the load reitor, R, boot the ain of the NA at hih frequency while thi topoloy matche the output to 50 Ω, without uin an output buffer for meaurement. 4. Ditortion Analyi Previou dein in [, 7] utilize a pmo tranitor a an auxiliary FET in weak inverion for imultaneou econd- and third-order ditortion cancellation in complementary derivative uperpoition method for wideband NA, providin acceptable bandwidth. In thi work by modifyin the complementary derivative uperpoition method in noie cancellation tructure, a pmo tranitor i alo ued for the ame reaon a hown in V out,ed. The effect of uin pmo tranitor in C-tae for econd-order ditortion cancellation i obviou due to the neative in added to ' m factor. Note that pmo tranitor alo reue the bia current of M. In thi circuit, we partially cancel the econdorder ditortion, and concentrate on full cancellation of third-order ditortion. Each term in Eq. (0 contribute to the third-order ditortion of V out. The firt term i the M ditortion and at low frequencie, the ratio of m and m factor are reduced to (R ( m new /C /R, which cancel out in the ame way a the M channel thermal noie current i cancelled in ection. The econd term in Eq. (0 that i due to third-order ditortion of M and M can be cancelled by biain thee two tranitor in the weak and tron inverion reion, repectively, with different " m polarity. Thee two cancellation criteria are formulated a: new m R R ( ( m m = and = mnew m R C m m ( + in the third-term of Eq. (0 i zero in two tone tet, when the frequency pace between two tone i reonance frequency of C and reonant tank, which act a a harmonic trap network. For thi application, IM i effective in relatively low frequency, and reonant tank decreae both ( + and third- 8 Iranian Journal of Electrical & Electronic Enineerin, Vol. 8, No., ep. 0

6 50 80 =.5nH =nh =.5nH =nh =.5nH 0 =4nH.5 term of Eq. (0. Becaue of the ame polarity of ' m and ' m factor, the value of the third-term in Eq. (0 can be ubtantial becaue ' m and ' m are fixed, once M and M are deined to atify Eq. ( However, the ize of M can be decreaed becaue of new input matchin technique uch that A (, i diminihed by lowerin ' m. In the next tep, hih frequency effect are conidered to deconvolve Eq. (0. In thi cae, " m and " m are frequency dependent, and for better ditortion cancellation the criteria can be formulated a ( ( + mro ( A( ov m ( + ro = ( m A o V ( ( ( c ( + + ( new m (a (b Fi. 7 (a the ratio of " m /" m without new and (b the ratio of " m /" m with new over the bandwidth. 0.5 For proper ditortion cancellation and extendin the bandwidth of thi cancellation, the ratio in Eq. ( hould have contant amplitude and phae π over the entire bandwidth. In thi topoloy, addin two inductor, new and, provide two deree of freedom for improvin the linearity. By plottin Eq. ( with and without new and by varyin in Fi. 7, the effect of thi technique i revealed. Takin into account the input matchin condition and the contour in Fi., new i choen to be 0. nh. The inductor, which reonate with paraitic capacitor in V, decreae the noie contribution of CG-tae. The proper value for thi inductor force it to reonate in the center of the required band. From Fi. 7, the inductance value mut be hiher than nh. We chooe nh due to area contrain. 5 imulation Reult The pot-layout imulation of the propoed NA in Fi. i deined with a RF CMO of 0.8µm. Fi. 8 how the input and output return loe. Thi fiure illutrate that the new input matchin tronly decreae the input return lo. Fi. 9 and 0 how the voltae ain and noie fiure, repectively. Note that the effect of i obviou becaue of ow noie fiure in reonance frequency of. For linearity analyi IIP 80 0 =.5nH =nh =.5nH =nh =.5nH =4nH and IIP are hown in Fi.. IIP in Fi. i obtained by varyin two frequency tone with 00 MHz pacin, and for IIP meaurement GHz pacin frequency i ued. In Fi. pacin i wept while one of the input tone i in the center frequency. Fi. and Fi. 4 how, repectively, IIP and db compreion point with weepin input power. In all fiure, potlayout imulation i compared with pre-imulation reult. Alo, Fi. 5 how layout of propoed NA. Finally, the performance of the propoed NA i compared in Table with imulation reult of prior dein to exhibit the benefit of the propoed circuit in hih frequency. All tranitor ize and other component value are reported in Table., (db pot layout imulation pre imulation with, new pre imulation without, new pot layout imulation pre imulation with, new pre imulation without, new Fi. 8 imulated -parameter,, and Voltae Gain. Av (db Av pot layout imulation Av pre imulation with, new Av pre imulation without, new Fi. 9 imulated Voltae Gain. Noie Fiure (db NF pot layout imulation NF pre imulation with, new NF pre imulation withou, new Fi. 0 imulated Noie Fiure. Mirzalou et al: A Hihly inear NA with Noie Cancellation for GHz UWB Receiver 9

7 0 IIP, IIP (dbm IIP pot layout imulation IIP pre imulation with, new IIP pre imulation without, new IIP pot layout imulation IIP pre imulation with, new IIP pre imulation without, new Fi. imulated IIP and IIP veru intermodulation frequency. Output Power (dbm * pdb pot layout imulation ** pdb pre imulation without, new Input -4 Power ** (dbm * Fi. 4 imulated -db compreion point in 8 GHz. 70µm 0 IIP, IIP (dbm IIP pot layout imulation IIP pre imulation with, new IIP pre imulation without, new IIP pot layout imulation IIP pre imulation with, new IIP pre imulation without, new Frequency pacin (GHz Fi. imulated IIP and IIP veru frequency pacin. 770µm Output Power (dbm * IIP pot layout imulation ** IIP pre imulation without, new Input Power (dbm 4 5 ** * Fi. imulated IIP in 8 GHz. Concluion A hihly linear NA with noie cancellation for GHz UWB receiver ha been deined in a 0.8 µm CMO technoloy. A new input matchin technique i examined. The Volterra erie kernel prove that additional inductor, which are added for Fi. 5 ayout of propoed NA. input matchin and noie cancellation, can be optimized to improve the ditortion cancellation in the above bandwidth. The propoed circuit incorporate pmo with nmo in the common-ource tae to realize imultaneou cancellation of econd- and third-order ditortion. imulation reult how that the maximum ain idb and noie fiure i below 5. db over the upper-band of UWB. The input matchin provide <-.5 db while <-7.5 db, <- db. The IIP and IIP of linear NA are over 4 dbm, while conume only 5 mw from.8 V upply. The chip area i 0.55 mm. Acknowledment The author would like to thank Education and Reearch Intitute for ICT (formerly, Iran Telecommunication Reearch Center for the financial upport of thi project. 40 Iranian Journal of Electrical & Electronic Enineerin, Vol. 8, No., ep. 0

8 Table imulation Reult Comparion with prior work Frequency Ref band NF Gain (db (db (db (GHz Thi IIP (dbm IIP (db Power (mw upply voltae (V Area (mm Technoloy < µm Work [] < µm [0] < nm [4] < µm [8] < µm [] < µm db BW except thi work and [4] A V Active area Table Device Dimenion M (7.0µm/0.8µm 5 C,C pf M (7.0µm/0.8µm 0 C,C 5pF M (7.0µm/0.8µm nh M 4 (7.0µm/0.8µm 0 in 0.7nH R 00Ω 0.9nH R 80Ω new 0.nH Reference [] Mirvakili A. and Yavari M., A Noie-Cancelin CMO NA Dein for the Upper Band of UWB D-CDMA Receiver, IEEE Int. ymp. on Circuit and ytem, Taipei, Taiwan, pp. 7 0, May 009. [] Chen W., iu G., dravko B. and Niknejad A. M., A hihly linear broadband CMO NA employin noie and ditortion cancellation, IEEE J. olid-tate Circuit, Vol. 4, No. 5, pp. 4-7, May 008. [] han H. and ánchez-inencio E., inearization Technique for CMO ow Noie Amplifier: A Tutorial, IEEE Tranaction on Circuit and ytem, Vol. 58, No., pp.-, Jan. 0. [4] Bruccoleri F., Klumperink E. A. M. and Nauta B., Wide-band CMO low-noie amplifier exploitin thermal noie cancelin, IEEE J. olid-tate Circuit, Vol. 9, No., pp. 75 8, Feb [5] iao C. F. and iu. I., A broadband noiecancelin CMO NA for. 0.-GHz UWB receiver, IEEE J. olid-tate Circuit, Vol. 4, No., pp.-4, ep [] Parvizi M. and Nabavi A., Improved derivative uperpoition cheme for imultaneou econdand third-order ditortion cancellation NA, Electronic etter, Vol. 45, No. 5, pp. 0-0, Dec [7] Im D., Nam I., Kim H. and ee K., A wideband CMO low noie amplifier employin noie and IM ditortion cancellation for a diital TV tuner, IEEE J. olid-tate Circuit, Vol. 44, No., pp. 8 98, March 009. [8] han H., Fan X. and ánchez-inencio E., A low-power, linearized, ultra-wideband NA dein technique, IEEE J. olid-tate Circuit, Vol. 44, No., pp. 0 0, Feb [9] Nuyen T. K., Kim C. H., Ihm G. J., Yan M.. and ee. G., CMO ow-noie Amplifier Dein Optimization Technique, IEEE Tranaction on Microwave Theory and Technique, Vol. 5, No. 5, pp 4-44, May 004. [0] Blaakmeer. C., Klumperink E. A. M., eenaert D. M. W. and Nauta B., Wideband Balun-NA With imultaneou Output Balancin, Noie- Cancelin and Ditortion-Cancelin, IEEEJ. olid-tate Circuit, Vol. 4, No., pp 4-50, June 008. [] Jindal R. P., Compact Noie Model for MOFET, IEEE Tranaction on Electron Device, Vol. 5, No. 9, pp. 05-0, ep. 00. Rana Mirzalou wa born in Khoy, Iran in 984. he received the B.c. deree from Tabriz Univerity, Tabriz, Iran, in 007, and the M.c. deree from Ilamic Azad Univerity cience and Reearch branch, in Tehran, Iran, in 0, both in electrical enineerin. Her reearch interet include RFcommunication circuit and analo electronic circuit dein. Abdolreza Nabavi received the B.c. and Mc. deree in Electrical En. from Tehran Univerity, Tehran, Iran, in 985 and 987, repectively, and the Ph.D. deree in Electrical Enineerin from McGill Univerity, in Canada in 99. ince 99, he ha been with the Faculty of Electrical and Computer Enineerin, Tarbiat Modare Univerity, Tehran, Iran. Hi reearch interet are in RFIC dein with emphai on Ultra Wideband and mm-wave ytem, and ow-power Analo and Diital Interated Circuit. Mirzalou et al: A Hihly inear NA with Noie Cancellation for GHz UWB Receiver 4

9 Ghafar Darvih wa born in Chalu, Iran, in 97. He received the B.c. deree from harif Univerity of Technoloy, Tehran, Iran, in 997 and the M.c. deree from Tehran Univerity, Tehran, Iran, in 000, both in Electrical enineerin, and the Ph.D. deree in electronic from the Ilamic Azad Univerity, cience and Reearch Branch, Tehran, Iran, in 008. From 000 to 005, he wa a Reearch taff Member with Electronic Component Indutrie, Tehran, Iran. He i currently an Aitant Profeor of Electronic with the Department of Electrical Enineerin, Ilamic Azad Univerity, cience and Reearch Branch, Tehran. Hi current reearch interet are the emiconductor optoelectronic device, the modelin and imulation of optoelectronic device, and tunable emiconductor laer. 4 Iranian Journal of Electrical & Electronic Enineerin, Vol. 8, No., ep. 0