T E L KO M N I KA  T e lec om m u n icat ion ,   Com p u t i n g,   E lec t r on ics   an d   Cont r ol   Vol.   18 ,   No.   1 F e br ua r y   2020 ,   pp.   2 64 ~ 2 71   I S S N:  1693 - 6930,   a c c r e dit e F ir s G r a de   by  Ke me nr is tekdikti ,   De c r e e   No:   21/E /KP T /2018   DO I 10. 12928/ T E L KO M NI KA . v18i1. 11365     264       Jou r n al  h omepage :   ht tp: // jour nal. uad . ac . id/ index . php/T E L K OM N I K A   A   lo w   p ow e r   w id e b a n d   va r ac t or le ss   VCO     u si n g   t u n a b le   ac t iv e   in d u c t o r       Om ar   F ar u q e 1 ,   Rum a n a   Akh t e r 2 ,   Md   T awf iq   A m in 3   1 D ep ar t men t   of   E l ect r i cal   a n d   E l ect r o n i c   E n g i n eer i n g ,   Ban g l ad e s h   A rm y   U n i v ers i t y   of   Sci e n ce   an d   T ech n o l o g y   (BA U S T ),   Ban g l ad e s h   2, 3 D e p art me n t   of   E l ec t ri ca l ,   E l ec t ro n i c   a n d   Co mm u n i cat i o n   E n g i n eer i n g ,   Mi l i t ar y   In s t i t u t e   of   Sci e n ce   an d   T ech n o l o g y   (MIS T ),   Ban g l ad e s h       Ar t icle   I n f o     AB S T RA CT   A r ti c le   h is tor y :   R e c e ived   Nov  3 ,   201 8   R e vis e d   Nov  3 ,   20 19   Ac c e pted   De c   18 ,   20 19       T h i s   p a p er   p res e n t s   a   w i d e b an d   v arac t o r l es s   v o l t a g e   co n t r o l l ed   o s ci l l a t o r   (V CO )   b as e d   on   t u n a b l e   act i v e   i n d u ct o r   in   90   nm   C MO S   p ro ces s   w h i ch   y i e l d s   a   t u n i n g   ra n g e   of   1 . 2 2   G H z   to   3 . 7   G H z   h a v i n g   a   t u n i n g   s co p e   of   1 0 0 . 5 % .   T h e   d es i g n ed   V CO   can   be   u s e d   fo r   w i d e b an d   w i re l es s   ap p l i ca t i o n s .   The   p r o p o s e d   V CO   co n s u mes   a   v ery   l o w   p o w er   ( 1 . 0 5 ~ 2 . 5 )   mW   w i t h     the   ch a n g e   of   t u n i n g   v o l t a g es   (0 . 3 ~ 0 . 9 )   V   an d   p r o v i d e s   a   d i fferen t i a l     o u t p u t   p o w er   of   (1 . 1 7 ~ - 5 . 1 3 )   d Bm.   The   V C O   ex h i b i t s   p h a s e   n o i s e   of     - 8 0 . 5 0   d Bc/ H z   @   2 . 7 4   G H z   an d   the   F i g u re   of   m eri t   (FO M)   is     - 1 4 7 . 7 3   d Bc/ H z   @   2 . 7 4   G H z   at   1 M H z   o ff s et   fre q u e n cy .   A c h i e v emen t   of   h i g h   t u n i n g   ra n g e   by   al t eri n g   t h e   i n d u ct a n ce   of   i n d u ct o r   w h i ch   p av e s   t h e   w ay   fo r   el i m i n a t i n g   t h e   MO S   v aract o r   t h a t   reced e s   the   o v eral l   s i l i c o n   area   co n s u m p t i o n ,   is   t he   n o t ew o rt h y   o u t co me   of   the   p r o p o s e d   V CO .   Fu r t h erm o re,   co n s i d eri n g   t h e   dc   p o w er   co n s u mp t i o n ,   F i g u re   of   m eri t   (FO M)   an d   co n s i s t e n cy   of   p erfo rma n ce   p aramet er s   o v er   t u n i n g   ran g e,   the   p ro p o s ed   V C O   o u t s t r i p s   t h e   o t h er   referred   V CO s .   K e y w o r d s :   Ac ti ve   inductor   F igur e   of   mer it   P ha s e   nois e   T uning   r a nge   VC O   Th i s   is   an   o p en   a c ces s   a r t i c l e   u n d e r   the   CC   BY - SA   l i ce n s e .     C or r e s pon din g   A u th or :   Oma r   F a r uqe ,     De pa r tm e nt   of   E lec tr ica l   a nd   E lec tr onic   E nginee r i ng,   B a nglade s h   Ar my   Unive r s it y   of   S c ienc e   a nd   T e c h nology   ( B AU S T ) ,   S a idpur   C a ntonm e nt,   S a idpur ,   B a nglade s h .   E mail:   o f a r uqe 20@gmail. c om       1.   I NT RODU C T I ON   In   the   moder n   e r a   of   c omm un ica ti on,   volt a ge   c ont r oll e d   os c il lator   ha s   gr a bbe d   a   s igni f ica nt   pos it ion,   gr a dua ll y   ha s   be c ome   indi s pe n s ibl e   in   many   c a s e s .   P ha s e   L oc ke d   L oop   ( P L L )   whic h   is   us e d   f or   f r e que nc y   mul ti pli e r ,   divi de r   a nd   FM   de tec tor ,   ha s   an   un a voidable   c omponent,   VC O   [1 - 3 ].   M or e ove r ,   f r e que nc y   jammer ,   f unc ti on   ge ne r a to r ,   a na log   to   dig it a l   c onve r ter ,   R F I D   ha s   an   inevitable   e leme nt,   whic h   is   volt a ge   c ontr oll e d   os c il lator   [ 4 - 10 ].   VC O   can   be   im plem e nted   in   two   major   wa ys :   LC   VC O   a nd   R ing   VC O   [ 11 ].   P owe r   c ons umpt ion,   tuni ng   r a nge ,   pha s e   nois e ,   s il icon   a r e a   c ons umpt ion   a nd   output   powe r   a r e   t he   ba s ic   pa r a mete r s   f or   c ha r a c ter izing   a   VC O.   T he   pha s e   nois e   is   a   kind   of   im pur it y   of   f r e que nc y   s pe c tr u m,   whic h   e volved   f r om   the   VC O’ s   e leme nts   [ 12 - 13] .   R ing   VC O   c ons umes   le s s   s il icon   a r e a   a nd   a l s o   c ons u mes   les s   powe r ,   whe r e   LC   VC O   c ons umes   a   lar ge   s il icon   a r e a   due   to   the   p r e s e nc e   of   s pir a l   or   pa s s ive   inductor   [ 11 ].     T he   s ubs ti tut ion   of   the   s pir a l   or   pa s s ive   inductor   with   a c ti ve   inductor   wil l   be   the   be s t   s olut ion   in   c a s e   of   lar ge   s il icon   a r e a   c ons umpt ion .   B a s ic   a c ti ve   inductor   is   the   two   ba c k   to   ba c k   c o nne c ted   tr a ns c onduc tor s   with   one   por t   c onne c ted   to   a   c a pa c it or .   C M OS   a c ti ve   inductor   pr ovides   s e ve r a l   a dva ntage s   s uc h   as   high   a nd   tunable   inducta nc e   as   we ll   as   qua li ty   f a c tor ,   low   s il icon   a r e a   c ons umpt ion   a nd   can   be   im pleme nted   in   wide   tuni ng   r a nge d   VC O   [ 14 ].   On   the   c ont r a r y,   poor   pha s e   nois e   pe r f o r manc e   a nd   dc   s tatic   Evaluation Warning : The document was created with Spire.PDF for Python.
T E L KO M NI KA   T e lec omm un   C omput   E C ontr o l         A   low   pow e r   w ideband  v ar ac tor les s   V C us ing  tunabl e   ac ti v e   inductor   ( Om ar   F ar uqe )   265   powe r   c ons umpt ion   a r e   the   two   major   dis a dva nta ge s   of   the   a c ti ve   inductor   [ 15 ].   How e ve r ,   the   mi ni mi z a ti on   of   both   of   thes e   two   dis a dva ntage s   will   be   the   ult i mate   goa l   of   a   good   de s ign.   T he   main   pivot a l   point   of   thi s   p r opos e d   r e s e a r c h   is   that   making   the   a c ti ve   inductor   tunable   by   a lt e r ing   the   pa r a mete r s   that   c ontr ol   the   inducta nc e   of   the   inducto r   without   a ny   phys ica l   c ha nge ,   whi c h   is   not   pos s ibl e   f or   s pir a l   inductor .   M or e ove r ,   tuni ng   c a pa bil it y   of   inductor   will   pr ovide   a   good   oppor tuni t y   to   tune   the   os c il lation   f r e que nc y   of   the   LC - VC O.   T he   m os t   c omm on   tec hnique   to   tune   the   os c il lation   f r e q ue nc y   of   VC O   is   obtaine d   by   im be dding   M OS   va r c tor s ,   wh ich   a dds   to   the   tot a l   s il icon   a r e a   c on s umpt ion.   How e ve r ,   if   high   tuni ng   r a nge   can   be   a c hieve d   by   a lt e r ing   the   i nduc tanc e   of   the   a c ti ve   inductor ,   then   the   va r a c tor s   can   be   e li mi na ted,   whic h   ult im a tely   r e duc e s   the   tot a l   s il ic on   a r e a   c ons umt ion.         2.   L I AN G   F E E DB AC K   RE S I S T AN CE   RE GU L A R   CA S CODE   AC T I VE   I ND UC T OR   L iang   uti li z e s   the   M a ne takis   r e gulate d   c a s c ode   a c ti ve   inductor   [1 6 ]   by   a dding   an   a ddit ional   r e s is tanc e .   M a ne taki s   r e duc e d   the   los s   e volved   f r om   the   s e r ies   r e s is tanc e   by   a dding   an   a ddit ional   r e gulate d   c a s c ode ,   whic h   is   a ls o   f ur ther   im pr ove d   by   L ian g   whe r e   a   f e e dba c k   r e s is tor     wa s   a dde d   f r om   the   dr a in   output   of   the   3   to   the   ga te   input   of   2   as   s hown   in   the   F igur e   1   [1 7 ] .       J 1 M 1 V b J 2 Z i n V D D M 2 M 3 J 3 M 4 V i n R f     F igur e   1.   S c he matic  diagr a m   of   L iang  f e e dba c r e s is tanc e   r e gular   c a s c ode   a c ti ve   inductor       T he   c or r e s ponding   e qua ti on   of   the   inducta nc e ,   s e r ies   r e s is tanc e ,   c a pa c it a nc e   a nd   c onduc tanc e   a r e   given   be low:      2 ( 1 + 1 ) 1 2     3 4 1 1 2 3 4    1   ( 1 )   2 + 1 1 + 1     s im il a r ly,   the   s e lf - r e s ona nt   f r e que nc y   a nd   qua li ty   f a c tor   at   s e lf - r e s ona nt   f r e que nc y   is :     = 1 2  1  2 ( 1 + 1 )            ( ) = ω 0 = 1 3 4 3 4 1 2  2  1 ( 1 + 1 )         3.   P ROP OS E D   T UN AB L E   AC T I VE   I ND UC T OR   As   idea l   c ur r e nt   s our c e   c a nnot   be   im pleme nted   pr a c ti c a ll y   so   it   s hould   be   r e plac e d   by   M OS   ope r a ted   in   s a tur a ted   r e gion.   F ig u r e   2   r e pr e s e nts   the   pr opos e d   tunable   a c ti ve   inductor   whe r e   the   idea l   c ur r e nt   s our c e s   1 ,   2   a nd   3   a r e   r e plac e d   by   M OSs   7 ,   6   a nd   5 ,   wh ich   a r e   ope r a ted   in   s a tur a ti on   r e gion.   Now     the   inducta nc e   of   the   inductor   given   by        2 ( 1 + 1 ) 1 2     ( 2)     Evaluation Warning : The document was created with Spire.PDF for Python.
                                I S S N :   1693 - 6930   T E L KO M NI KA   T e lec omm un   C omput   E C ontr o l Vol.   18 ,   No .   1 F e br ua r 2020 :    2 64   -   2 71   266   So   the   inducta nc e   is   di r e c tl y   pr opo r ti ona l   to   the   ga te   to   s our c e   c a pa c it a nc e   of   M OS   2   a nd   inver s e ly   pr opor ti ona l   to   tr a ns c onduc tanc e   of   M OS   1   a nd   2   a nd   the   c ha nge   of   the   a ny   of   thes e   thr e e   pa r a mete r s   will   r e s ult   in   the   c ha nge   of   inducta nc e .   T he   c u r r e nt   th r o ugh   a   M OS   ope r a ted   in   the   s a tur a ti on   r e gion   is   giv e n   by :       =   1 2  ( v gs ) 2   ( 3)     T he   incr e ment   of   the   ga te   to   s our c e   volt a ge   will   c a us e   the   incr e ment   of   the   dr a in   c ur r e nt   6   of     the   M OS   6   .   T he   inc r e a s e   of   the   d r a in   c ur r e nt   6   will   c a us e   the   inc r e a s e   of   the   d r a in   c ur r e nt   of   M OS   2 ,   f inally   the   tr a ns c onduc tanc e   2   a c c or ding   to   the   f oll o wing   e qua ti on.       =      ( 4)     T he   inducta nc e   will   be   de c r e a s e d   a nd   the   r e duc ti on   of   the   inducta nc e   will   incr e a s e   the   os c il lation   f r e que nc y,   whe n   the   inductor   will   be   im pleme nt e d   in   LC   os c il lator .   Now ,   if   a   good   tuni ng   r a ng e   can   be   a c hieve d   f r om   a lt e r ing   the   inducta nc e   only   ther e   will   be   a   notew or thy   oppor tun it y   to   e li mi na te   the   va r a c tor s   as   a   tuni ng   pa r a mete r .   An   im pleme nted   va r a c tor   is   nothi ng   but   mos f e t   with   s hor ted   dr a in,   body   a nd   s our c e .   S o,   the   int e gr a ti on   M OS   va r a c tor   will   boos t   up   t he   s il icon   a r e a   c ons umpt ion.   S o ,   the   e li mi na ti on   of   M OS   va r a c tor   will   r e c e de   the   s il icon   a r e a   c ons umpt ion .   T uning   the   inducta nc e   by   c ha nging   the   g m   will   r e s ult   in   a   dis a dva ntage   that   is   the   va r iation   of   dc   powe r   c ons umpt ion.   T his   will   a lt e r   the   pha s e   noi s e   of   LC   VC O   as   a c c or ding   to   the   e qua ti on   give n   be low   pha s e   nois e   ha s   de pe nde nc e   on   the   dc   powe r   dis s ipation   [1 8 ].     (  ) = 1 0 l o g   { 2  [ 1 + ( 0 2  ) 2 ] ( 1 +  1 / 3  ) }   ( 5)     w he r e ,    =   F r e que nc y   of f s e t   f r om   the   os c il lation   f r e que nc y   0   =   Qua li ty   f a c tor   of   the   os c il lator   =   E xc e s s   nois e   f a c tor   =   B olt z mann   c ons tant   =   Abs olut e   Ke lvi n   tempe r a tur e   =   P owe r   dis s ipation   S im il a r ly,   the   a lt e r na ti on   on   dc   powe r   dis s ipation   will   a ls o   a lt e r   the   F igur e   of   m e r it ,   whic h   de f ines   the   ove r a ll   pe r f o r manc e   of   LC   VC O   by   c ounti ng   thr e e   major   pa r a mete r s :   powe r   c ons umpt ion ,   o s c il lation   f r e que nc y   a nd   pha s e   nois e   [1 9 ] .     = (  ) + 10 log ( 1  ) 20 log (  )   ( 6)     T he   r e duc ti on   of   the   va r iation   of   thes e   two   pe r f o r mi ng   pa r a mete r s   ( pha s e   nois e   a nd   F igur e   of   m e r it )   will   be   the   major   tar ge t   of   thi s   pr opos e d   de s ign.   A   s igni f ica ntl y   low   va lue   a nd   low   va r iation   of   DC   powe r   c ons umpt ion   will   pa ve   the   wa y   f or   the   a c hieve ment   of   thi s   goa l.   T a ble  1   s hows   the  W /L   r a ti os   f or   a ll   the   mos f e ts   us e in  the   pr opos e tunable   a c ti ve   inducto r   de picte in  F igur e   2 .   F igu r e   s hows   the  va r iation  of   the  induct a nc e   va lue  of   the  pr opos e tunable   a c ti ve   inductor   with   the   va r iation   o f   tuni ng   volt a ge   r a n ging  f r om   0. 3   V   to   0 . 9   V .   F inally   the   T a ble   2   r e pr e s e nts     the  numer ica l   va lue  o f   inducta nc e   f o r   di f f e r e nt   f r e que nc ies   with  the  va r iation  o f   tuni ng   volt a ge s .       T a ble  1.   W idt hs   a nd  l e ngths   of   im pleme nted  tr a ns is tor s   M O S   W id th  ( μ m)   L e ngt h ( nm)   M 1   12   120   M 2   22   140   M 3   25   140   M 4   4.2   300   M 5   4   120   M 6   6   300   M 7   4   120     Evaluation Warning : The document was created with Spire.PDF for Python.
T E L KO M NI KA   T e lec omm un   C omput   E C ontr o l         A   low   pow e r   w ideband  v ar ac tor les s   V C us ing  tunabl e   ac ti v e   inductor   ( Om ar   F ar uqe )   267   M 1 V D D M 2 M 3 M 4 V i n R f V b V b V t u n e M 6 M 5 M 7 I D 6   1 2 3 4 5 6 7 - 60 - 40 - 20 0 20 40 60 80 V t u n e =0 . 3 V V t u n e =0 . 4 V V t u n e =0 . 5 V V t u n e =0 . 6 V V t u n e =0 . 7 V V t u n e =0 . 8 V V t u n e =0 . 9 V F r e q u e n c y ( G H z) I n d u c t a n c e ( n H ) 0 . 2     F igur e   2.   L iang  f e e dba c r e s is tanc e   r e gular   c a s c ode   a c ti ve   inductor   with  s a tur a ted  M OS  a s   c ur r e nt  s our c e     F igur e   3.   Va r iation   of   inducta nc e   with  the  va r iatio of     the  c ontr ol  vol tage         T a ble   2.   I nduc tanc e   at   di f f e e nt   f r e que nc ies   f or   dif f e r e nt   tuni ng   vol tage s   V tu n e   I nduc ta nc e ( nH )   @   1G H z   I nduc ta nc e ( nH )   @   2G H z   I nduc ta nc e ( nH )   @   3G H z   I nduc ta nc e ( nH )   @   4G H z   P ow e r   C ons umpt io n     of   AI   ( mW )   0.3   43.3   55.3   57.3   - 50.2   0.259   0.4   16.4   20.3   31.7   48.7   0.331   0.5   9.77   11.8   17.2   32.8   0.446   0.6   7.24   8.76   12.4   21.4   0.588   0.7   6.03   7.34   10.3   15.7   0.737   0.8   5.36   6.57   9.21   12.3   0.878   0.9   4.95   6.11   8.50   99.9   1.007       4.   P ROP OS E D   T UN AB L E   AC T I VE   I ND UC T OR   B ASE D   VCO   NM OS   LC   VC O   topol ogy,   whic h   ha s   c r os s   c oupled   pa ir   of   NM OS   tr a ns is tor s ,   with   a   tail   c ur r e nt   s our c e   is   the   mos t   c omm only   us e d   topol ogy.   T he   LC   tank   c ir c uit   is   loade d   at   the   dr a in   ter mi na l   a nd   a   c ouple   of   LC   tank   f or ms   the   dif f e r e nti a l   c onf igu r a ti on.   T he   ba c k   to   ba c k   c onne c ted   NM OSs   a r e   in   c omm o n   s our c e   c onf igur a ti on,   so   that   a   lar ge   vo lt a ge   ga in   can   be   a c hieve d,   whic h   is   one   of   the   f unda menta l   c ond it ions   of     the   B a r kha us e n   c r it e r ia   f or   s us taining   os c il lation.   Anothe r   c ondit ion   r e ga r ding   the   tot a l   pha s e   s hif t   that   it   s hould   be   0 o   or   360 o   is   pr ovided   by   thes e   NM OS s   whic h   p r ovides   180 o   pha s e   s hif t   as   they   a r e   in   c omm on   s our c e   c onf igur a ti on.   F igur e   4   p r e s e nts   the   pr opos e d   a c ti ve   inductor   ba s e d   volt a ge   c ontr oll e d   os c il lat or   ba s e d   on   mos t   c omm only   us e d   NM OS   LC   VC O   topol ogy.   T he   ind ica ted   dott e d   s e c ti on   is   L iang   r e gular   c a s c a d e   a c ti ve   inductor   a nd   the   p r e s e nc e   of   two   a c ti ve   inductor s   indi c a tes   the   dif f e r e nti a l   c onf igur a ti on .   V c o n   at     the   ga te   ter mi na l   of   the   M OS   M 6   is   the   tuni ng   volt a ge   whic h   c ha nge s   the   ga te   volt a ge   a nd   f inally     the   inducta nc e   of   the   a c ti ve   inductor .   M n e g s   a r e   th e   two   M OSs ,   us e d   as   ne ga ti ve   r e s is tor   whom   r e s is tanc e   is   c ontr oll e d   by   M OS   M 8   ope r a ted   in   s a tur a ti on   r e g ion.   T he   ove r a ll   c ontr ibut ion   of   thes e   e leme nts   w il l   r e s ult     a   dif f e r e nti a l   output   whic h   a r e   take n   f r om   the   tw o   output   ter mi na ls   Out1   a nd   Out2 .   S upply   volt a g e   V DD   is   us e d   1   V   a nd   the   W /L   r a ti os   of   a ll   M OSs   a r e   given   in   T a ble   3.       T a ble  3.   W idt hs   a nd  lengths   of   im pleme nted  tr a ns is tor s   f or   the   pr opos e VC O   M O S   W id th   ( μ m)   L e ngt h   ( nm)   M 1   12   120   M 2   22   140   M 3   25   140   M 4   4.2   300   M 5   4   120   M 6   6   300   M 7   4   120   M n e g   30   100   M 8   30   100 ( mul ti pl ie r s  =  3)     Evaluation Warning : The document was created with Spire.PDF for Python.
                                I S S N :   1693 - 6930   T E L KO M NI KA   T e lec omm un   C omput   E C ontr o l Vol.   18 ,   No .   1 F e br ua r 2020 :    2 64   -   2 71   268   V b M 8 V D D V c o n M n e g M n e g M 1 M 2 M 3 R f V b V b M 6 M 7 M 1 M 2 M 3 M 4 R f V b V b M 6 M 5 M 7 O u t 1 O u t 2     F igur e   4.   P r opos e tunable   a c ti ve   inductor   ba s e VC O       5.   S I M UL AT I ON   RE S UL T S   T r a ns ient,   ps s   ( with   5   ha r moni c s ) ,   pnois e ,   dc   a na lys is   ha d   be e n   pe r f or med   to   a c hieve   ou tput   os c il lation,   os c il lation   f r e que nc y,   pha s e   nois e ,   out put   powe r   a nd   dc   powe r   dis s ipation   of   the   pr opos e d   VC O.   T he   os c il lator   s hows   an   os c il lation   f r e que nc y   r a nging   f r om   1. 22   GHz   to   3 . 7   GHz   with   the   va r iation   of   c ontr ol   volt a ge   r a nging   f r om   0. 3   V   to   0. 9   V.   T he   tuni ng   s c ope   is   100. 5%   a nd   the   os c il lator   yields   a   pha s e   nois e   of     - 77. 01   dB c /Hz   to   - 76. 44   dB c /Hz   in   the   whole   tuni ng   r a nge .   T he   dc   powe r   dis s ipation   is   1. 05   mW   to     2. 50   mW   whe r e   the   V DD   is   1V.   T he   dc   powe r   c ons umpt ion   is   ve r y   low   whic h   is   one   of   the   majo r   f oc a l   point s   of   the   pr opos e d   VC O.   T he   p r opos e d   VC O   p r ovides   dif f e r e nti a l   output   powe r   of   1 . 17   dB m   to   - 5. 13   d B m   with   the   incr e ment   of   tuni ng   f r e que nc y.   T a ble   4   s h ows   the   pe r f or manc e   pa r a mete r s   of   the   pr opos e d   a c ti ve   inductor   ba s e d   dif f e r e nt ial   VC O   f o r   the   va r iation   of   c ontr ol   volt a ge .       T a ble  4.   P e r f o r manc e   pa r a mete r s   f o r   di f f e r e nt   tuni ng  volt a ge   v c o n   V c o n     ( V )   F r e q.   (f)   G H z   ( P S S   O ut put   O s c il la ti on   V ol ta ge   ( P S S )  @ f   P ha s e   N oi s e   @   1M H z   of f s e t   dB c / H z   P ow e r   D is s @ 1V   ( mW )   O ut put  P ow e r   ( 50 - ohm   R)   F ig ur e   of   m e r i ( F O M )   @  1   M H z  O f f s e t   D if f e r e nt ia l   D if f e r e nt ia l   D if f e r e nt ia l   (P - P)   + ve   - ve   + ve   - ve   dB c / H z   dB F   mV   mV   ( dB m)   0.3   1.224   396.5  t - 3 95.8   361.6   - 77.01   1.0496   1.165   - 138.555   288.555         181.0   180.6       - 4.846   - 4.866       0.4   2.123   366 to   - 366   344.4   - 80.02   1.19091   740.7   - 145.8   295.8         172.3   172.1       - 5.274   - 5.286       0.5   2.735   337.5  t - 3 37.9   326.2   - 80.50   1.41426   269.9   - 147.734   297.734         163.3   162.9       - 5.740   - 5.761       0.6   3.141   295 to   - 294 .5   289.0   - 79.97   1.68951   782.3   - 147.634   297.634         144.7   144.3       - 6.790   - 6.816       0.7   3.404   250.5  t - 2 50.8   246.8   - 78.83   1.97745   - 2.154   - 146.509   296.509         123.6   123.2       - 8.162   - 8.187       0.8   3.578   210.5  t - 2 11   208.3   - 77.54   2.25122   - 3.625   - 145.089   295.089         104.4   103.9       - 9.628   - 9.664       0.9   3.696   176.9  t - 1 77   175.2   - 76.44   2.50185   - 5.131   - 143.812   293.812         87.78   87.38       - 11.13   - 11.17           F igur e   5   s hows   the   dif f e r e nti a l   output   os c il lation   f or   the   c ontr ol   volt a ge   V c o n   =   0 . 6   V,   whe r e   F igu r e   6   r e pr e s e nts   pha s e   nois e   vs   f r e que nc y   of f s e t   f o r   tuni ng   volt a ge s   of   0 . 3   V,   0 . 6   V   a nd   0. 9   V   a nd   the   pha s e   nois e s   a r e   - 77. 01,   - 79. 97   a nd   - 76. 44   dB c /Hz   at   1   M Hz   of f s e t   r e s pe c ti ve ly.   F igu r e   7   s hows   the   va r iation   of   tuni ng   f r e que nc y   with   the   c ha nge   of   tuni ng   volt a ge .   T he   a c c ieve d   f r e que nc y   r a nge   is   1 . 22   to   3. 7   GH z .       Evaluation Warning : The document was created with Spire.PDF for Python.
T E L KO M NI KA   T e lec omm un   C omput   E C ontr o l         A   low   pow e r   w ideband  v ar ac tor les s   V C us ing  tunabl e   ac ti v e   inductor   ( Om ar   F ar uqe )   269   5 5 . 5 6 6 . 5 7 7 . 5 8 8 . 5 9 9 . 5 1 0 - 0 . 3 - 0 . 2 - 0 . 1 0 0 . 1 0 . 2 0 . 3 T i m e ( n s ) D i f f e r e n t i a l   O u t p u t     ( V o l t )     F igur e   5.   Dif f e r e nti a output   os c il lation  f or   tun ing  volt a ge   V c o n   =   0 . 6   V       10 4 10 5 10 6 10 7 - 110 - 100 - 90 - 80 - 70 - 60 - 50 - 40 - 30 - 20 F r e q u e n c y   O f f s e t ( H z) P h a s e   N o i s e   ( d B c / H z ) V t u n e =0 . 3 V V t u n e =0 . 6 V V t u n e =0 . 9 V     F igur e   6.   P ha s e   nois e   vs   f r e que nc of f s e f o r   va r io us   tuni ng  volt a ge       A   pe r f or manc e   pa r a mete r ,   F igur e   of   m e r it   de f i ne d   by   ( 6 ) ,   c ons ider ing   pha s e   nois e ,   dc   powe r   c ons umpt ion   a nd   os c il lation   f r e que nc y   whic h   is   de picte d   in   F igur e   8   with   the   va r iation   of   tuni ng   volt a ge s .   T he   plot   s hows   that   the   F igur e   of   m e r it   ( F OM )   is   a lm os t   c ons tant   with   the   a lt e r a ti on   of   os c il lator s   os c il lation   f r e que nc y   whic h   is   the   ou tcome   of   the   pr opos e d   d e s ign.   T he   F igur e   of   m e r it   can   a ls o   be   de f ined   in   t e r ms   of   dB F   whic h   is   given   by   ( 7 )   [ 20 ] .     (  ) = 20 log ( )     10   l o g   (  )   ( 7)     F inally,   the  main  c ont r ibut ion   of   the   pr opos e VC is   the   e li mi na ti on   o f   M OS   va r a c tor s   whic h   a r e   us e f or   the   tuni ng   pur pos e .   M OSF E T   with  s h or ted  dr a in ,   s our c e   a nd   body  c a n   be   us e a s   c a pa c it or .     T he   c ha nge   of   the  ga te  volt a ge   of   M OSF E T   r e s ult s   in  the  c ha n ge   of   the  c a pa c it a nc e   of   thi s   M OS  va r a c tor .   T o   a c hieve   higher   va lue   of   c a pa c it a nc e ,   we   ha ve   to   mul ti ply  the   number   of   M OS   whic ul ti mate ly  i nc r e a s e s     the  s il icon  a r e a   c ons umpt ion.   S o,   the  e li mi na ti on   o f   M OS  va r a c tor ,   unde r   s ome  c ondit ions   c a be   pos s ibl e ,   if   high  tuni ng  r a nge   c a be   a c hieve d.   B ut  tuni ng   of   the  inductor   e nge nde r s   the  va r iation  o f   pe r f or manc e   pa r a mete r   s uc a s   dc   powe r   c ons umpt ion,   pha s e   n ois e   a nd  ult im a tely  the   F igur e   of   m e r it .   T he   da ta   t a ble  a nd  the  plot s   p r e s e nted  c lea r ly  poin out   that   th e   va r ia ti ons   a r e   high ly  l im it e d.   Af te r   a ll ,   r e duc ti on   of   th e   s il icon  a r e a   c ons umpt ion  by  e li mi na ti ng   M OS  va r a c to r   a nd  a the  s a me  ti me  the   li mi tation   of   va r i a ti on  of   pe r f or manc e   pa r a mete r s   a r e   the  yielding   of   the  p r opos e de s ign  whic outdoes   the  other   de s igns   a s   r e f e r r e in  T a ble  5 .       Evaluation Warning : The document was created with Spire.PDF for Python.
                                I S S N :   1693 - 6930   T E L KO M NI KA   T e lec omm un   C omput   E C ontr o l Vol.   18 ,   No .   1 F e br ua r 2020 :    2 64   -   2 71   270   0 . 2 0 . 3 0 . 4 0 . 5 0 . 6 0 . 7 0 . 8 0 . 9 1 1 1 . 5 2 2 . 5 3 3 . 5 4 ( 0 . 3 ,   1 . 1 2 2 ) ( 0 . 4 ,   2 . 1 2 3 ) ( 0 . 5 ,   2 . 7 3 5 ) ( 0 . 6 ,   3 . 1 4 1 ) ( 0 . 7 ,   3 . 4 0 4 ) ( 0 . 8 ,   3 . 5 7 8 ) ( 0 . 9 ,   3 . 6 9 6 ) T u n i n g   V o l t a g e ( V o l t ) F r e q u e n c y ( G H z )     F igur e   7.   F r e que nc vs   tuni ng  volt a ge   f or   the  pr op os e VC O       0 . 2 0 . 3 0 . 4 0 . 5 0 . 6 0 . 7 0 . 8 0 . 9 1 - 1 6 5 - 1 6 0 - 1 5 5 - 1 5 0 - 1 4 5 - 1 4 0 - 1 3 5 - 1 3 0 - 1 2 5 T u n i n g   V o l t a g e ( V o l t ) F i g u r e   o f   M e r i t ( d B c / H z )     F igur e   8.   F igu r e   of   m e r it   ( F OM )   vs   tuni ng  vol tage s   f or   the   pr opos e VC O       T a ble   5.   P e r f o r manc e   c ompar is on   of   VC O   with   ot he r   de s igns   R e f e r e nc e s   [ 21]   [ 22]   [ 23]   [ 24]   [ 25]   T hi s   w or k   C M O S   T e c hnol ogy   180   nm   180   nm   180   nm   180   nm   130   nm   90   nm   S uppl y   V ol ta ge   ( V )   1.8   1.8   1.8   1.8   1.2   1   P ow e r   ( mW )   44.6   16.27   29.38   11.9   3.2   1.05~ 2.5   T uni ng   R a nge   ( G H z )   1.26 ~ 2.98   0.1~ 2.5   ----   0.55~ 3.8   1.913 ~ 2.491   1.22~ 3.69   T uni ng   R a nge   (%)   81.13   184.6   ----   149   26.24   100.5   O ut put   P ow e r ( dB m)   - 5.3 ~ - 18.7   5~ 15   0.21   @   5.5G H z   3~ - 11   ----   1 .16~ 5.13   ( di f f e r e nt ia l)   P N @ 1M H z   ( dB c /Hz )   - 90   93~ - 80   - 80.31   - 89~ - 78   - 80.23   - 80.50   @   2.74   G H z   F O M   ( dB c /Hz )   @ 1M H z   - 141.11   @   2.4   G H z   - 120.88~   135.84   - 140.43   @   5.5   G H z   - 133.5 ~   - 138.84   - 140.81~   - 143.106   - 147.734   @   2.74   G H z       6.   CONC L USI ON   A   low   powe r   tunable   a c ti ve   inductor   ba s e d   volt a ge   c ontr oll e d   os c il lator   f or   wi r e les s   a ppli c a ti ons   ha s   be e n   pr opos e d   in   thi s   r e s e a r c h   whic h   pr ov ides   a   tuni ng   r a nge   of   1. 22   GHz   to   3. 7   GHz   ha ving   a   tuni ng   s c ope   of   100. 5 % .   T he   pr opos e d   VC O   e xihi bts   l ow   dc   powe r   dis s ipation   c ha r a c ter is ti c s   ( 1. 05~2 . 5)   mW   with     the   c ha nge   of   tuni ng   volt a ge s   ( 0. 3~0 . 9)   V   a long   with   a   good   dif f e r e nti a l   output   powe r   of   ( 1 . 17~ - 5. 13)   dB m .   F ur ther mor e ,   e li mi na ti on   of   M OS   va r a c tor   whic h   ha s   be e n   a c hivevd   by   tuni ng   the   inducta nc e   o nly,   ha s   f a c il iate d   the   wa y   to   r e duc e   the   s il icon   a r e a   c ons umpt ion.   L ow   powe r   c ons umpt ion,   s tabilt y   of   pe r f or manc e   pa r a mete r s   a nd   f inally   the   good   F igur e   of   m e r it   ( F OM )   a r e   the   s pe c if ic   outcome s   of   the   p r opos e d   de s ign   whic h   outper f or m   the   othe r   r e f e r r e d   de s igns .       Evaluation Warning : The document was created with Spire.PDF for Python.
T E L KO M NI KA   T e lec omm un   C omput   E C ontr o l         A   low   pow e r   w ideband  v ar ac tor les s   V C us ing  tunabl e   ac ti v e   inductor   ( Om ar   F ar uqe )   271   RE F E RE NC E S   [1   K .   N .   Mi n h ad ,   Z .   K azemi ,   M .   Bi n   Ib n e   Reaz,   J .   J a l i l ,   an d   N .   K ama l ,   D e s i g n   of   a   C u rren t   St ar v ed   Ri n g   O s c i l l at o r   Bas ed   V C O   fo r   Ph as e - L o c k ed   L o o p ,”   TE LKO M NIKA   (I n d o n e s i a n   Jo u r n a l   of   E l ect r i c a l   a n d   E n g i n ee r i n g ) ,   v ol.   12,   no.   9,   pp.   6 6 6 7 - 6 6 7 2 ,   2 0 1 4 .   [2   S.   Su man ,   K.   G.   Sh arma ,   an d   P.   K.   G h o s h ,   D es i g n   of   PL L   u s i n g   i mp r o v e d   p erfo rma n ce   ri n g   V CO , ”  2 0 1 6   In t e r n a t i o n a l   Co n f e r en ce   on   E l ec t r i ca l ,   E l ec t r o n i cs ,   and   O p t i m i z a t i o n   Tech n i q u es   (ICE E O T) ,   Ch e n n a i ,   2 0 1 6 ,     pp.   3 4 7 8 - 3 4 8 3 .   [3   X.   Z o u ,   X.   J i an g ,   D.   X i a o ,   an d   S.   L i u ,   W i d e   cap t u r e   ran g e   PL L   w i t h   LC - V CO , ”  i n   2 0 0 5   IE E E   I n t e r n a t i o n a l   S ym p o s i u m   on   M i cr o wa ve,   A n t e n n a ,   P r o p a g a t i o n   a n d   EMC   Tech n o l o g i e s   f o r   W i r el e s s   Co m m u n i ca t i o n s ,   Bei j i n g ,   v o l .   2 ,   p p .   9 5 3 - 9 5 6 ,   2 0 0 5 .   [4   D.   H al d er   an d   A . K .   G u p t a,   U l t ra   l o w   p o w er   ri n g   V C O   b as e d   t u n ea b l e   s i g n a l   g e n erat o r   fo r   n e u ral   s t i mu l at i o n ,   2 0 1 5   4 th   I n t e r n a t i o n a l   Co n f e r en ce   on   R el i a b i l i t y,   In f o c o m   Tec h n o l o g i es   a n d   O p t i m i z a t i o n   ( ICR ITO )   (Tr en d s   a n d   F u t u r e   D i r ect i o n s ) ,   N o i d a,   pp.   1 - 6 ,   2 0 1 5 .   [5   M.   Si ri p ru c h y a n u n   an d   P.   W ard k ei n ,   A   t emp erat u re - i n s e n s i t i v e   V CO   an d   d eri v a t i v e   PW M   s i g n al   g e n erat o r , ”  i n   A S IC O N   2 0 0 1 .   2 0 0 1   4 th   I n t e r n a t i o n a l   C o n f er e n ce   on   A S IC   P r o ceed i n g s   (Ca t .   No . 0 1 TH 8 5 4 9 ) ,   S h an g h a i ,   Ch i n a,     pp.   2 2 4 - 2 2 7 ,   2 0 0 1 .   [6   G.   Bl as co ,   E.   I s ern ,   an d   E.   Mart i n ,   D e s i g n   of   a   s t a b l e   p u l s e   g e n erat o r   s y s t em   b a s ed   on   a   Ri n g - V CO   P h as e - L o c k ed   L o o p   u s i n g   1 8 0 n m   CM O S   t ec h n o l o g y , ”  2 0 1 5   Co n f e r e n ce   on   D e s i g n   of   Ci r c u i t s   a n d   I n t e g r a t ed   S ys t em s   (D C IS ) ,   E s t o r i l ,   p p .   1 - 6 ,   2 0 1 5 .   [7   D.   Rai t eri ,   P.   V.   L i es h o u t ,   A.   V.   Ro ermu n d ,   an d   E.   Can t a t o re,   An   o rg a n i c   V C O - b a s ed   ADC   fo r   q u as i - s t at i c   s i g n a l s   ac h i e v i n g   1 L SB   IN L   at   6b   res o l u t i o n , ”  2 0 1 3   I E E E   I n t e r n a t i o n a l   S o l i d - S t a t e   Ci r cu i t s   Co n f e r en ce   D i g e s t   of   Tech n i ca l   P a p er s ,   San   Fran c i s c o ,   CA ,   pp.   1 0 8 - 1 0 9 ,   2 0 1 3 .   [8   J.   Park ,   H.   Ry u ,   an d   D.   Baek ,   77   G H z   s i g n al   g e n erat o r   w i t h   CMO S   t ech n o l o g y   fo r   a u t o mo t i v e   rad ar   ap p l i ca t i o n , ”  in   2 0 1 1   In t er n a t i o n a l   S o C   D e s i g n   Co n f e r en ce ,   J e j u ,   p p .   444 - 4 4 5 ,   2 0 1 1 .   [9   W.   L ai ,   J.   H u an g ,   C.   H s u ,   a n d   P.   Y an g ,   L o w   Po w er   V CO   a n d   Mi x er   fo r   Co m p u t i n g   M i racas t   a n d   M o b i l e   Bl u e t o o t h   A p p l i ca t i o n s , ”  2 0 1 4   I n t e r n a t i o n a l   Co n f e r en ce   on   Cyb e r - E n a b l e d   D i s t r i b u t e d   Co m p u t i n g   a n d   K n o w l e d g e   D i s co ve r y ,   Sh an g h a i ,   pp.   4 2 5 - 4 2 8 ,   2 0 1 4 .   [1 0   Y.   Z h o u ,   Z.   Ch en g ,   K.   Fu ,   J.   Li ,   an d   X.   Z h o u ,   D e s i g n   of   l o w   p h a s e   n o i s e   LC   V CO   fo r   UHF   RFID   rea d er,   2 0 0 9   15 th   A s i a - P a c i f i c   Co n f e r en ce   on   Co m m u n i ca t i o n s ,   Sh an g h a i ,   pp.   4 1 4 - 4 1 7 ,   2 0 0 9 .   [1 1   J.   Pri n z i e,   J.   Ch ri s t i an s en ,   P.   Mo rei ra,   M.   St ey aer t   an d   P.   L ero u x ,   Co mp ar i s o n   of   a   65   nm   CMO S   Ri n g -   an d     LC - O s ci l l a t o r   Bas e d   PL L   in   T erms   of   T ID   an d   SE U   Se n s i t i v i t y ,   IE E E   Tr a n s a c t i o n s   on   Nu c l ea r   S ci e n ce ,   vol.   64,   no.   1,   pp.   2 4 5 - 2 5 2 ,   J a n   2 0 1 7 .   [1 2   M.   T.   A mi n ,   On   t h e   s e l ect i o n   of   p as s i v e   el eme n t s   fo r   l o w   p h as e   n o i s e   LC   t a n k   V CO   in   65   nm   p ro ce s s ,   2 0 1 6   3 rd   In t e r n a t i o n a l   Co n f er e n ce   on   E l ect r i c a l   E n g i n eer i n g   and   I n f o r m a t i o n   C o m m u n i c a t i o n   Tech n o l o g y   (ICE E I CT) ,   D h a k a,   pp.   1 - 5 ,   2 0 1 6 .   [1 3   M.   Hsu,   R.   J h o n g ,   an d   Y.   L ee,   Ph as e   n o i s e   red u ct i o n   of   CMO S   V CO   b a s ed   on   cro s s - co u p l ed   t o p o l o g y   w i t h   s h u n t   cap aci t o r,   2 0 1 5   IE E E   In t er n a t i o n a l   Co n f e r en ce   on   E l ec t r o n   D ev i ces   a n d   S o l i d - S t a t e   Ci r cu i t s   (E D S S C) ,   Si n g ap o re,   pp.   5 8 6 - 5 8 9 ,   2 0 1 5 .   [1 4   M.   M.   Rej a,   I.   M.   Fi l an o v s k y ,   an d   K.   Mo ez,   Wide   t u n ab l e   CMO S   act i v e   i n d u ct o r,   E l ect r o n i c s   Let t e r s ,   v o l .   44,   no.   25,   p p .   1 4 6 1 - 1 4 6 3 ,   4   D ecemb er   2 0 0 8 .   [1 5   R.   Meh ra   an d   R.   C.   G u rj ar,   LC   V CO   U s i n g   A ct i v e   In d u ct o r   fo r   L o w   Ph as e   N o i s e   an d   W i d e   T u n i n g   Ran g e,   In t e r n a t i o n a l   Jo u r n a l   of   In n o v a t i ve   R e s ea r ch   in   S ci e n ce,   E n g i n eer i n g   a n d   Tech n o l o g y,   v o l .   5,   no.   7,     pp.   1 3 3 4 5 - 1 3 3 5 0 ,   J u l y   2 0 1 6 .   [1 6   K.   Man et a k i s ,   S.   Park ,   A.   Pay n e ,   an d   S.   Set t y ,   A.   T h a n ach a y an o n t   an d   C.   T o u maz o u ,   W i d e b an d   CMO S   a n a l o g   cel l s   fo r   v i d e o   an d   w i rel e s s   co mm u n i cat i o n s ,   P r o ce ed i n g s   of   Th i r d   In t er n a t i o n a l   Co n f e r en ce   on   E l ec t r o n i cs ,   Ci r cu i t s ,   a n d   S y s t e m s ,   Ro d o s ,   G reece,   vol.   1 ,   pp.   2 2 7 - 2 3 0 ,   1 9 9 6 .   [1 7   J.   L i an g ,   C.   Ho,   C.   Kuo,   an d   Y.   Ch an ,   CMO S   RF   b an d - p a s s   fi l t er   d e s i g n   u s i n g   t h e   h i g h - q u a l i t y   act i v e   i n d u ct o r,   IE ICE   Tr a n s .   on   E l ec t r o n ,   v o l .   E 8 8 - C ,   n o .   1 2 ,   p p .   2 3 7 2 2 3 7 6 ,   D ec   2 0 0 5 .   [1 8   F.   Y u an ,   CM O S   A c t i ve   I n d u ct o r s   a n d   Tr a n s f o r m er s ,   1 st   ed .   U n i t e d   St at e s :   S p ri n g er,   2 0 0 8 .   [1 9   M.   B.   I.   Reaz,   M.   A.   M.   Ali,   T.   G.   Ch an g ,   an d   J.   J al i l ,   A   L o w   Po w er   3 - St a g e   V o l t a g e - Co n t r o l l ed   Ri n g ,   E l ek t r o n i ka   Ir   E l ek t r o t ec h n i ka ,   v o l .   1 9 ,   no.   8 ,   2 0 1 3 .   [2 0   T.   I.   A h re n s   a n d   T . H .   L ee,   A   1 . 4 - G H z   3 - mW   CM O S   LC   l o w   p h as e   n o i s e   V C O   u s i n g   t ap p ed   b o n d   w i re   i n d u c t an ce s ,   In t e r n a t i o n a l   S ym p o s i u m   on   Lo w   P o we r   E l ect r o n i c s   a n d   D e s i g n ,   Mo n t ere y ,   pp.   16 - 19 1 9 9 8 .   [2 1   J.   T.   Y an g ,   S.   K.   H s i e h ,   an d   P.   J.   T s ai ,   A   W i d e   T u n i n g   Ran g e   V o l t ag e - C o n t ro l l e d   O s c i l l at o r   w i t h   A ct i v e   In d u c t o rs   fo r   Bl u et o o t h   A p p l i ca t i o n s ,   CS S ' 1 0   P r o cee d i n g s   of   t h e   4 th   i n t er n a t i o n a l   co n f e r en ce   on   Ci r cu i t s ,   s ys t e m s   and   s i g n a l s ,   p p .   39 - 42 ,   2 0 1 0 .   [2 2   H.   B.   K i aa,   A.   K.   A ’ai n a ,   an d   I.   G ro u t b ,   W i d e   t u n i n g - ran g e   CMO S   V CO   b as e d   on   a   t u n ab l e   act i v e   i n d u c t o r,   In t e r n a t i o n a l   Jo u r n a l   of   E l ect r o n i c s ,   v o l .   1 0 1 ,   no.   1,   p p .   88 - 9 7 ,   D ecemb er   2 0 1 4 .   [2 3   N.   C.   Sh i raz i ,   E.   A b i ri ,   an d   R.   H amze h y a n ,   A   5 . 5   G H z   V o l t ag e   Co n t r o l   O s c i l l at o r   ( V CO )   w i t h   a   D i fferen t i a l   T u n ab l e   A ct i v e   an d   Pas s i v e   In d u c t o r,   In t e r n a t i o n a l   Jo u r n a l   of   In f o r m a t i o n   a n d   E l ec t r o n i cs   E n g i n ee r i n g ,   v o l .   3,   no.   5,   pp.   4 9 3 - 4 9 7 ,   Sep t emb er   2 0 1 3 .   [2 4   A.   Sab erk ari   an d   S.   Sei fo l l ah i ,   Wide   t u n i n g   ran g e   CM O S   Co l p i t t s   V C O   b as e d   on   t u n a b l e   act i v e   i n d u ct o r,   M a j l e s i   Jo u r n a l   of   Tel ec o m m u n i c a t i o n   D evi ce s ,   v o l .   1,   no.   1,   p p .   11 - 1 5 ,   March   2 0 1 2 .   [2 5   G h o rb e l ,   F.   H ad d ad ,   W.   Rah aj an d ra i b e,   H.   Bart h él emy ,   M.   L o u l o u ,   an d   H.   Mn i f,   D es i g n   an d   i m p l eme n t a t i o n   of   an   act i v e   i n d u ct o r - b a s ed   LC   o s c i l l at o r,   ICM   2 0 1 1   P r o c eed i n g ,   p p .   1 - 4 ,   2 0 1 1 .   Evaluation Warning : The document was created with Spire.PDF for Python.