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Design and Analysis of RF and Microwave Systems European M asterofR esearch on Inform ation Technology European M asterofR esearch on Inform ation Technology IMPEDANCE TRANSFORMERS AND TAPERS Lecturers: Lluís Pradell ([email protected] ) Francesc Torres ([email protected]) March 2010

IMPEDANCE TRANSFORMERS AND TAPERS

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IMPEDANCE TRANSFORMERS AND TAPERS. Lecturers: Lluís Pradell ( [email protected] ) Francesc Torres ([email protected]). March 2010. The quarter-Wave Transformer* ( i ). A quarter-wave transformer can be used to match a real impedance Z L to Z 0. Z in. Z 0. Z 1. Z L. - PowerPoint PPT Presentation

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Page 1: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

IMPEDANCE TRANSFORMERS

AND TAPERS

Lecturers: Lluís Pradell ([email protected])

Francesc Torres ([email protected])

March 2010

Page 2: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

The quarter-Wave Transformer* (i)

Zin

Z1 ZLZ0

A quarter-wave transformer can be used to match a real impedance ZL to Z0

40

L

in Z

ZZ

21

tjZZ

tjZZZZ

L

Lin

1

11

tgtgt

If The matching condition at fo is 01 ZZZ L

At a different frequency and the input reflection coefficient is

00

0

0

0

20 ZZtjZZ

ZZ

ZZ

ZZ

LL

L

in

inZin

220

0

cos

41

1

ZZ

ZZ

L

Lin

The mismatch can be computed from:

0ZZ in

*Pozar 5.5

Page 3: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

The quarter-Wave Transformer (ii)

If Return Loss is constrained to yield a maximum value , the

0

0

2

2

1cos

ZZ

ZZ

L

L

m

mm

frequency that reaches the bound can be computed from:

m

Where for a TEM transmission line

00

0

24

2

4 f

f

f

v

v

f

vp

pp

And the bound frequency is related to the design frequency as:

02 f

f mm

Page 4: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

The quarter-Wave Transformer (iii)

Finally, the fractional bandwdith is given by

0,05m

02

fl

f

0/ 10LZ Z

0/ 4LZ Z

0/ 2LZ Z

18,1 %BW

4,5 %BW

0

0

2

1

0

0 2

1cos

42

2

ZZ

ZZ

f

fff

L

L

m

mm

Page 5: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

Multisection transformer* (i)

That is, in the case of small reflections the permanent reflection is dominated by the two first transient terms: transmission line discontinuity and load

The theory of small reflections

01

010 ZZ

ZZ

1

1

ZZ

ZZ

L

LL

In the case of small reflections, the reflection coefficient can be approximated taking into account the partial (transient) reflection coefficients:

jLe 2

0

L

L0

40

*Pozar 5.6

20

Page 6: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

0

1Z2Z LZNZ0Z

1 2

N

Multisection transformer (ii)The theory of small reflections can be extended to a multisection transformer

2 4 2 10 1 2

1

... ; ( 0,1,..., )j j jN i iN i

i i

Z Ze e e i N

Z Z

It is assumed that the impedances ZN increase or decrease monotically

( 2) ( 2)0 1 ...jN jN jN j N j Ne e e e e

0 1 1 2 2, , ,...N N NSymmetric

The reflection coefficients can be grouped in pairs (ZN may not be symmetric)

Page 7: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

0 1 / 2

12 cos cos( 2) ... cos( 2 ) ...

2jN

i Ne N N N i for N even

0 1 ( 1) / 22 cos cos( 2) ... cos( 2 ) ... cosjNi Ne N N N i

for N odd

Finite Fourier Series: periodic function (period: )

Multisection transformer (iii)

The reflection coefficient can be represented as a Fourier series

Any desired reflection coefficient behaviour over frequency can be synthesized by properly choosing the coefficients and using enough sections:

•Binomial (maximally flat) response

•Chebychev (equal ripple) response

i

L

02

F

0

0

ZZ

ZZ

L

LL

Page 8: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

Binomial multisection matching transformer (i)

2(1 ) 2 cosNj N N jNA e Ae

0

0

2 N L

L

Z ZA

Z Z

Binomial function

AN2)0(

The constant A is computed from the transformer response at f=0:

The transformer coefficients are computed from the response expansion:

n

N

n

jnNn eCA

0

2)( !!

!

nnN

NC N

n

The transformer impedances Zn are then computed, starting from n=0, as:

0

1 ln2lnZ

ZC

Z

Z LNn

N

n

n

Nnn AC

Page 9: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

Binomial multisection matching transformer (ii)

Page 10: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

Binomial multisection matching transformer (iii)

11/

1arccos arccos

2

NN

m mm

LA

Bandwidth of the binomial transformer

mNN

m A cos2

The maximum reflection at the band edge is given by:

02

fl

f

1

0/ 2LZ Z

71 %

( 3)

BW

N

m

05.0The fractional bandwitdh is then:

1/

0

0 0

2( ) 4 4 12 2 arccos

2

N

mm mf f f

f f A

Page 11: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

Chebyshev multisection matching transformer

1( ) cos( cos ), 1nT x n x for x 1( ) cosh( cosh ), 1nT x n x for x

0

0

1

1cos

L

LN

m

Z ZA

Z ZT

1

11 0

0

cosh1

cos11 1 coshcosh cosh

cos

L

m

L

mm L

m NZ Z

N Z Z

cos

cosjN

Nm

A e T

Chebyshev polynomial

02

fl

f

0,05m

0/ 2LZ Z

102 %

( 3)

BW

N

Page 12: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

Chebyshev transformer design

Page 13: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

Chebyshev transformer design

Application: Microstrip to rectangular wave-guide transition: both source and load impedances are real.

Rectangular guide

Ridge guide: five λ/4 sections: Chebychev design

Steped ridge guideMicrostrip line

Ridge guidesection

Page 14: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

TRANSFORMER EXAMPLE (1):ADS SIMULATION

S_ParamSP1

Step=10 MHzStop=20 GHzStart=0 GHz

S-PARAMETERS

MSUBMSub1

Rough=0 umTanD=9e-4T=17.5 umHu=1.0e+036 umCond=5.8e+7Mur=1Er=2.17H=257 um

MSub

TermTerm2

Z=100 OhmNum=2

TermTerm1

Z=50 OhmNum=1

MLINTL5

L=5509.460000 umW=767.037000 umSubst="MSub1"

MLINTL3

L=5678.81 umW=283.802 umSubst="MSub1"

MSTEPStep3

W2=207.139 umW1=283.802 umSubst="MSub1"

MSTEPStep1

W2=429 umW1=616.935 umSubst="MSub1"

MSTEPStep2

W2=283 umW1=429.655 umSubst="MSub1"

MLINTL2

L=5611.44 umW=429.655 umSubst="MSub1"

MLINTL1

L=5548.47 umW=616.935 umSubst="MSub1"

MSTEPStep4

W2=616 umW1=767.037 umSubst="MSub1"

MLINTL4

L=5725.100000 umW=207.139000 umSubst="MSub1"

Chebyshev transformer, N = 3, |M|=0.05 (ltotal = 3/4)

87,14 70,71 100 57,37 50

Page 15: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

TRANSFORMER EXAMPLE (2):ADS SIMULATION

2 4 6 8 10 12 14 16 180 20

-40

-30

-20

-10

-50

0

freq, GHz

dB

(S(1

,1))

2 4 6 8 10 12 14 16 180 20

-0.6

-0.4

-0.2

-0.8

0.0

freq, GHz

dB

(S(1

,2))

CHEBYSCHEV N=3

2 4 6 8 10 12 14 16 180 20

0.1

0.2

0.3

0.0

0.4

freq, GHz

mag(S

(1,1

))

BW = 102 %0,05m

microstrip loss

Page 16: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

Tapered lines (i)

LZ

zL0

0Z Z z

zz z z

Z Z Z

In the limit, when z 0:

Taper: transmission line with smooth (progressive) varying impedance Z(z)

Z

Z

ZZZ

ZZZ

2

zZdZ

zd2

1

The transient ΔΓ for a piece Δz of transmission line is given by:

dz

zfd

zfdz

zfLd n

)(

1

dzdz

zfLdzfd

zfn

2

1

)(2

1

This expression can be developed taking into account the following property:

Page 17: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

Tapered lines (ii)

dz

dz

zZLdzd n

2

1

Taking into account the theory of small reflections, the input reflection coefficient is the sum of all differential contributions, each one with its associated delay:

Fourier Transform

LnzjzjL

in dzdz

zZLdeezd

0

22

0 2

1

L Taper electrical length

zZ•Exponential taper

•Triangular taper

•Klopfenstein taper

dz

zZLd n

Page 18: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

Exponential Taper

0zZ z Z e

for 0 <z < L

0

1ln LZ

L Z

0ln / sin( )

2j LLZ Z L

L eL

(sinc function)

L

LZLZ

ZZ 00

dz

zZLd n

L zj

in dze0

2

2

1

Fourier Transform

Lmin2max

L

Page 19: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

Triangular taper

22

ln2 0

024 2

1 ln2 0

0

Zz LZL

Zz z LL ZL

Z e

Z e

Z z

20

20

4ln

0

4( ) ln

lnL

L

Lz Z

ZL

ZL z

ZL

Zd

Z

dz

0 / 2

/ 2

z L

L z L

0 / 2

/ 2

z L

L z L

2

0

1 sin( / 2)ln

2 / 2j L LZ L

L eZ L

(squared sinc function)

- lower side lobes- wider main lobe L

Page 20: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

Klopfenstein Taper

2 2cos

coshj L

L

L AL e

A

:passband L A

0

0 0

1ln

2L L

LL

Z Z Z

Z Z Z

coshL

m A

LShortest length for a specified |M|

Lowest |M| for a specified taper length

( )L A

ltaper =

0/ 2LZ Z

Based on Chebychev coefficients when n→∞. Equal ripple in passband

Page 21: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

Microstrip to rectangular wave-guide transition

Example of linear taper: ridged wave-guide

Microstrip line

Ridgedguide

Rectangularguide

SECTION A-A’

SECTION B-B’SECTION C-C’

Page 22: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

Rectangular wave-guide to finline to transition

Example of taper: finline wave guide

Finline mixer configuration

Page 23: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

TAPER EXAMPLE (1):ADS SIMULATION

TermTerm2

Z=100 OhmNum=2

TermTerm1

Z=50 OhmNum=1

MTAPERTaper1

L=LtotW2=W11W1=W1Subst="MSub1"

MSUBMSub1

Rough=0 milTanD=9e-4 T=17.5 umHu=3.9e+34 milCond=5.8e7 Mur=1.0 Er=2.17 H=10.0 mil

MSub

ADS taper model

S_ParamSP1

Step=10 MHzStop=20 GHzStart=0 GHz

S-PARAMETERS

Page 24: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

TAPER EXAMPLE (2):ADS SIMULATION

Aproximation to exponential taper using ADS : 10 sections of

MLINTL10

L=L11W=W11Subst="MSub1"

MLINTL9

L=L10W=W10Subst="MSub1"

MLINTL7

L=L8W=W8Subst="MSub1"

MLINTL8

L=L9W=W9Subst="MSub1"

MLINTL6

L=L7W=W7Subst="MSub1"

MSTEPStep4

W2=W5W1=W4Subst="MSub1"

MSTEPStep2

W2=W3W1=W2Subst="MSub1"

MLINTL15

L=L2W=W2Subst="MSub1"

MSTEPStep1

W2=W2W1=W1Subst="MSub1"

MLINTL14

L=L1W=W1Subst="MSub1"

MLINTL19

L=L6W=W6Subst="MSub1"

MLINTL18

L=L5W=W5Subst="MSub1"

TermTerm4

Z=100 OhmNum=4

MSTEPStep9

W2=W11W1=W10Subst="MSub1"

MSTEPStep8

W2=W10W1=W9Subst="MSub1"

MSTEPStep7

W2=W9W1=W8Subst="MSub1"

MSTEPStep6

W2=W8W1=W7Subst="MSub1"

MSTEPStep5

W2=W7W1=W6Subst="MSub1"

MSTEPStep11

W2=W6W1=W5Subst="MSub1"

MLINTL17

L=L4W=W4Subst="MSub1"

MLINTL16

L=L3W=W3Subst="MSub1"

TermTerm3

Z=50 OhmNum=3

MSTEPStep3

W2=W4W1=W3Subst="MSub1"

50 53,59 57,44 61,56 65,97 70,71

75,79 81,22 87,05 93,30 100

Page 25: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

TAPER EXAMPLE (3):ADS SIMULATION

Aproximation to exponential taper using ADS : 10 sections of

50 53,59 57,44 61,56 65,97

70,71 75,79 81,22 87,05 93,30

100 VARVAR11Ltot=L1+L2+L3+L4+L5+L6+L7+L8+L9+L10

EqnVar

VARVAR23L11=2.290040 mm

EqnVar

VARVAR22W11=207.139000 um

EqnVar

VARVAR6L3=2.219510 mm

EqnVar

VARVAR5W3=615.883000 um

EqnVar

VARVAR4L2=2.211550 mm

EqnVar

VARVAR3W2=688.516000 um

EqnVar

VARVAR1W1=767.037000 um

EqnVar

VARVAR2L1=2.203780 mm

EqnVar

VARVAR8W4=548.755000 um

EqnVar

VARVAR7L4=2.227670 mm

EqnVar

VARVAR10W6=429.647000um

EqnVar

VARVAR9L6=2.244580 mm

EqnVar

VARVAR13W7=377.052000 um

EqnVar

VARVAR12L7=2.253330 mm

EqnVar

VARVAR15W5=486.783000 um

EqnVar

VARVAR14L5=2.236020 mm

EqnVar

VARVAR17W8=328.727000 um

EqnVar

VARVAR16L8=2.262270 mm

EqnVar

VARVAR19W9=284.432000 um

EqnVar

VARVAR18L9=2.271390 mm

EqnVar

VARVAR21W10=243.966000 um

EqnVar

VARVAR20L10=2.280660 mm

EqnVar

Page 26: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

TAPER EXAMPLE (4):ADS SIMULATION

m3freq=m3=-32.452

9.980GHzm1freq=m1=-22.116

7.170GHz

2 4 6 8 10 12 14 16 180 20

-60

-40

-20

-80

0

freq, GHz

dB(S

(1,1

))

9.880G-32.36

m3

dB(S

(3,3

))

7.170G-22.12

m1

EXPONENTIAL / ADS TAPER

− 10 section approx.− ADS model

Page 27: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

TAPER EXAMPLE (5):ADS SIMULATION

2 4 6 8 10 12 14 16 180 20

0.1

0.2

0.3

0.0

0.4

freq, GHz

mag

(S(1

,1))

mag

(S(3

,3))

Exponential taper

0,05m

ltaper = @ 10 GHz

− 10 section approximation− ADS model

Page 28: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

TAPER EXAMPLE (6):ADS SIMULATION

m1freq=m1=-9.824

49.41GHz

m2freq=m2=-65.843

9.980GHz

20 40 60 800 100

-60

-40

-20

-80

0

freq, GHz

dB(S

(1,1

))dB

(S(3

,3))

48.85G-9.995

m1

9.980G-65.84

m2

10 section taper: periodicity in frequency

(li=/2)

(li=/10)

− ADS model − 10 section approximation is periodic.

Page 29: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

MATCHING NETWORKS

LEVY DESIGN

Lecturers: Lluís Pradell ([email protected])

Francesc Torres ([email protected])

Page 30: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

MatchingNetwork

(passive lossless)

Z0

fVs

22 21

11

11 1dL d

tavS avS

P PG

P P M

f

Minimize |1 (f)| Maximize Gt(2)

Pd1 PdL

MATCHING NETWORKS

Page 31: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

CONVENTIONAL CHEBYSHEV FILTER (1)

20

0

0

0 0

1si si pi pi

isi

ipi

L C L C

g ZL

w

gC

w Z

20 0 0

020 0

1,

1,

sisi i

pipi i

wC

L g Z

wZL

C g

' 0

0

2 1 2 1

0 0

20 2 1

1

w

f fw

f

0Z

1SL 1SC

2PL 2PC

3SL 3SC

PNL PNC

1 1 0.N NR g Z

Conversion from Low-Pass to Band-

Pass filter

1g 3g

1 1n ng R 0g

2g ng

LC low-pass filter

Center frequency

Relative bandwidth

Page 32: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

CONVENTIONAL CHEBYSHEV FILTER (2)

( 0)

( 1)

22 2

2

2

1'

1 '

1

1

1

10log 10log 1

MAX Tn

MIN Tn

MAX

MIN

tn n

t

tn

tn

t

GT

G

G

Gr dB

G

1

' 2( )Gt

1'

2( )Gt

2

1

1 n

1

1 0 2

20 1. 2

1

1

cos cos , 1

cosh cosh , 1n

n x xT x

n x x

Pass-band ripple

Chebychev polynomials

Page 33: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

CONVENTIONAL CHEBYSHEV FILTER (3) 0

1

12 2

1

1

2 • sin( ) 12 , sinh( ) ,sinh( )

2 1 2 14 • sin( ) • sin( )

2 2•sin ( )

( 1,2,...., 1)

2 • sin( )2

n

i i

n n

g

ng x ax na

i in ng g

ix

n

i n

ng gx

Fix pass-band ripple and filter order “n”

g0, g1,.., gn+1 are the low-pass LC filter coefficients: 1'1 w

Page 34: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

APPLICATION TO A MATCHING NETWORK

1 1 1

1

1 1

1

' '

''

'

,

,

s s e s e

e ss s e

e s

L L L L L

C CC C C

C C

1

1 1

e1 e

0 0

20

2.sin .R.R 2. . .

1

s

s s

g nLw x w

L C

eR

'1SL '

1SC

2PL2PC

eLeC

PNL PNC

1 1.N N eR g R

TransistorM odel

1 1 ?n s e

rgiven a x g L L

n

Solution (?): increase n (n constant) a, x decrease

or increase n (n constant) a, x decrease

Transistor modeled with a dominant RLC behaviour in the pass-band to be matched

The final design may be out of specifications: n too high (too many sections) or r too large

Page 35: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

LEVY NETWORK (1)

( 0)

( 1) 2

2

1

10log 10log 1

MAX Tn

MIN Tn

MAX

MIN

t n

nt

n

tn

t

G K

KG

Gr dB

G

1

1

cos cos , 1

cosh cosh , 1n

n x xT x

n x x

2

2 2' ( 1)

1 'n

t nn n

KG K

T

' 2( )Gt

1'

2( )Gt

21n

n

K

1 0 2

20 1. 2

21n

n

K

nK

nK

SOLUTION: An additional parameter is introduced: Kn<1

Page 36: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

LEVY NETWORK (2)

0

1

12 2 2

1

1

2.sin2

2 1 2 14.sin .sin

2 2 , ( 1,2...., 1)sin 2. . .cos

2.sin2

i i

n n

g

ngx y

i in ng g i n

i ix y x y

n n

ng gx y

2

2

sinh ( )

sinh

1

sinh

sinh1 , ( 1)

sinhn n

n

x a

n

y b new freedom degree

nbK K

a

na

0

1

2 2 21

32

1

2.sin4

1 2·

1

2.sin1 4·

g

gx y

gg x y

gg x y

Example: n = 2

2

2

2 22

sinh ( )

sinh

1

sinh 2

sinh 21 , ( 1)

sinh 2

y b new freedom degree

bK

a

a

K

x

a

SOLUTION: Additional design equations

Page 37: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

LEVY NETWORK (3)

1 1 1 1

1 1 1 1

2 20

2 20

1 1

1 1

s s e e s e s ee

s s e e s e s ee

If L C L C take C C L L

If L C L C take L L C C

Design procedurea) Choose Cs1 or Ls1 taking into account the load to be matched

c) Compute x-y from the parameter g1

b) Choose network order (n) and compute g1

1

2.sin2nx y

g

1

1

01 1

e 0 e

. .

. .s

s

L w wg or g

R C R

Page 38: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

LEVY NETWORK (4)

2 2

cosh cosh

tgh a tgh b

a b

OPTIMAL DESIGN: minimize

2

2

2

1

cosh1 1

1 coshMAX

t

ntMIN

n

G

nbKG

na

0MAX

b

sinh sinha b x y ct

cosh cosh

tgh na tgh nb

a b

22 2 2

2

C Cx

For n=2: 2C x y

Select Ls1 (or Cs1) and n. Compute g1. and x-y. Then determine x, y and Kn, n:

x y b

a nnK

d) Choose x, compute y, max

Example: usual case n=2: Optimum x

The matched bandwith can be increased from ~5% to ~20% with n=2, with moderate Return Loss requirements (~20 dB)

Page 39: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

LEVY NETWORK EXAMPLE (1)

M atch ingN etwork

LeC e

R e R

15,2

0,528,86

0,62

50

e

ee

e

R

L nHf GHz

C pF

R

10

2

5,56,4226

7,5

f GHzf GHz

f GHz

Page 40: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

LEVY NETWORK EXAMPLE (2)

dBRL 75.17min

dBRL 98.23min

0

20

10

21

22 2

2

3

0,62 ( )

10,99

0,8195

2sin( )4 1,7257

21,978 1,434

20,2535 0,2509

0,996 0,015

0,114 0,071

0,4903 2,57 , 0,239

1

S e e

SS

S e

n tMAX

n tMIN

p p

C C pF f f

L nHC

wg

C R

C x yg

C Cx a

y b

K G dB

G dB

g C pF L nH

g

3 3, 2928 19,65eR g R

1

2

0

5,5

7,5

6,4226

20,3114

6,4226

f Ghz

f Ghz

f GHz

w

dBRL 75.17min

Page 41: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

LEVY NETWORK EXAMPLE (3):ADS SIMULATION

5 6 7 84 9

-20

-15

-10

-5

-25

0

freq, GHz

dB

(S(2

,1))

dB

(S(2

,2))

5 6 7 84 9

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

-1.0

0.0

freq, GHz

dB

(S(2

,1))

LEVY NETWORK (LUMPED COMPONENTS)

TFTF1T=1.5951

S_ParamSP1

Step=100 MHzStop=9.0 GHzStart=4 GHz

S-PARAMETERS

LLs

R=L=0.99 nH

TermTerm2

Z=50 OhmNum=2

TermTerm1

Z=15.2 OhmNum=1

CC2C=2.57 pF

LLp

R=L=0.239 nH

CCeC=0.62 pF

A transformer is necessary since g3≠1 (R3≠50 Ω). This transformed must be eliminated from the design

Page 42: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

Norton Transformer equivalences

STEPS:1) the capacitor C2 is pushed towards the load through the transformer2) The transformer is eliminated using Norton equivalences

Page 43: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

LEVY NETWORK EXAMPLE (4):ADS SIMULATION

5 6 7 84 9

-20

-15

-10

-5

-25

0

freq, GHz

dB

(S(2

,1))

dB

(S(2

,2))

5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.54.5 9.0

-0.8

-0.6

-0.4

-0.2

-0.0

-1.0

0.2

freq, GHz

dB

(S(2

,1))

S_ParamSP1

Step=100 MHzStop=9.0 GHzStart=4 GHz

S-PARAMETERS

LLe

R=L=0.52 nH

LL2

R=L=0.23 nH

CC2C=1.02 pF

LLp

R=L=0.38 nH

LLs

R=L=0.33 nH

TermTerm2

Z=50 OhmNum=2

TermTerm1

Z=15.2 OhmNum=1

CCeC=0.62 pF

Page 44: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

SMALL SERIES INDUCTANCES AND PARALLEL CAPACITANCES IMPLEMENTED USING SHORT TRANSMISSION LINES

L l

Z0h 0 0 0 00

2 h h

lf L Z l f L Z

C

l

Z0l 0 0 0 00

2 l l

lf C Y l f C Y

L, C elements are then synthesized by means of short transmission lines:

Page 45: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

SMALL SERIES INDUCTANCES AND PARALLEL CAPACITANCES IMPLEMENTED USING SHORT

TRANSMISSION LINES: EXAMPLE

10

0

10,33 106

50S h

lL nH Z for

22 0

0

10,23 73,85

50h

lL nH Z for

32 0

0

11,02 15,26

10l

lC pF Z for

Page 46: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

LEVY NETWORK EXAMPLE ADS SIMULATION (5):

5 6 7 84 9

-25

-20

-15

-10

-5

-30

0

freq, GHz

dB(S

(1,1

))dB

(S(2

,1))

5.5 6.0 6.5 7.0 7.55.0 8.0

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

-1.2

0.2

freq, GHz

dB(S

(2,1

))

MSUBMSub3

Rough=0 milTanD=9e-4 T=0.689 milHu=3.9e+34 milCond=5.8e7 Mur=1.0 Er=2.17 H=10.0 mil

MSub

MLINTL8

L=715.898000 umW=178.873000 umSubst="MSub3"

MLSCTL4

L=948.7005301751 umW=262 umSubst="MSub3"

MLINTL10

L=3278.680000 umW=3586.240000 umSubst="MSub3"

TermTerm2

Z=50 OhmNum=2

MLINTL9

L=701.096000 umW=396.160000 umSubst="MSub3"

S_ParamSP1

Step=10 MHzStop=9 GHzStart=4 GHz

S-PARAMETERS

LLe

R=L=0.52 nH

CCeC=0.62 pF

TermTerm1

Z=15.2 OhmNum=1

Page 47: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

LEVY NETWORK EXAMPLE: ADS SIMULATION (6):

5 6 7 84 9

-10

-5

-15

0

freq, GHz

dB

(S(1

,1))

dB

(S(1

,2))

5.5 6.0 6.5 7.0 7.55.0 8.0

-2.0

-1.5

-1.0

-0.5

-2.5

0.0

freq, GHz

dB

(S(2

,1))

MTEETee1

W3=262.0 umW2=0.39616 mmW1=0.178873 mmSubst="MSub3"

MSTEPStep1

W2=3586.24 umW1=396.16 umSubst="MSub3"

MSUBMSub3

Rough=0 milTanD=9e-4 T=0.689 milHu=3.9e+34 milCond=5.8e7 Mur=1.0 Er=2.17 H=10.0 mil

MSub

MLINTL8

L=715.898000 umW=178.873000 umSubst="MSub3"

MLSCTL4

L=948.7005301751 umW=262 umSubst="MSub3"

MLINTL10

L=3278.680000 umW=3586.240000 umSubst="MSub3"

TermTerm2

Z=50 OhmNum=2

MLINTL9

L=701.096000 umW=396.160000 umSubst="MSub3"

S_ParamSP1

Step=10 MHzStop=9 GHzStart=4 GHz

S-PARAMETERS

LLe

R=L=0.52 nH

CCeC=0.62 pF

TermTerm1

Z=15.2 OhmNum=1

Page 48: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

LEVY NETWORK EXAMPLE (7):

ADS SIMULATION: optimization

VARVAR4L4=3213.73 um opt{ 2000 um to 4000 um }

EqnVar

VARVAR3L3=1074.12 um opt{ 500 um to 1400 um }

EqnVar

VARVAR2L2=368.083 um opt{ 300 um to 1200 um }

EqnVar

VARVAR1L1=553.743 um opt{ 300 um to 1200 um }

EqnVar

OptimOptim1

SaveCurrentEF=noUseAllGoals=yes

UseAllOptVars=yesSaveAllIterations=noSaveNominal=yesUpdateDataset=yesSaveOptimVars=noSaveGoals=yesSaveSolns=noSeed= SetBestValues=yesNormalizeGoals=noFinalAnalysis="SP1"StatusLevel=4DesiredError=0.0MaxIters=25OptimType=Random

OPTIM

MLINTL10

L=L4W=3586.240000 umSubst="MSub3"

MLSCTL4

L=L3W=262 umSubst="MSub3"

MLINTL9

L=L2W=396.160000 umSubst="MSub3"

MLINTL8

L=L1W=178.873000 umSubst="MSub3"

GoalOptimGoal2

RangeMax[1]=7.5 GHzRangeMin[1]=5.5 GHzRangeVar[1]="freq"Weight=Max=Min=-0.5SimInstanceName="SP1"Expr="insertion_loss"

GOAL

GoalOptimGoal1

RangeMax[1]=7.5 GHzRangeMin[1]=5.5 GHzRangeVar[1]="freq"Weight=Max=-10Min=SimInstanceName="SP1"Expr="matching"

GOALMeasEqnMeas1

insertion_loss=dB(S(2,1))matching=dB(S(1,1))

EqnMeas

MTEETee1

W3=262.0 umW2=0.39616 mmW1=0.178873 mmSubst="MSub3"

MSTEPStep1

W2=3586.24 umW1=396.16 umSubst="MSub3"

MSUBMSub3

Rough=0 milTanD=9e-4 T=0.689 milHu=3.9e+34 milCond=5.8e7 Mur=1.0 Er=2.17 H=10.0 mil

MSub

TermTerm2

Z=50 OhmNum=2

S_ParamSP1

Step=10 MHzStop=9 GHzStart=4 GHz

S-PARAMETERS

LLe

R=L=0.52 nH

CCeC=0.62 pF

TermTerm1

Z=15.2 OhmNum=1

Page 49: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

LEVY NETWORK EXAMPLE (8):ADS SIMULATION: optimization

5 6 7 84 9

-20

-15

-10

-5

-25

0

freq, GHz

dB

(S(1

,1))

dB

(S(2

,1))

5.0 5.5 6.0 6.5 7.0 7.54.5 8.0

-1.0

-0.5

0.0

0.5

1.0

-1.5

1.5

freq, GHz

dB

(S(2

,1))

Page 50: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

LEVY NETWORK EXAMPLE (9):ADS SIMULATION: optimization

VARVAR2L2=554.494 um opt{ 200 um to 1200 um }

EqnVar

VARVAR4L4=2193.75 um opt{ 2000 um to 4000 um }

EqnVar

VARVAR3L3=1332.32 um opt{ 500 um to 1400 um }

EqnVar

VARVAR1L1=485.326 um opt{ 300 um to 1200 um }

EqnVarGoal

OptimGoal1

RangeMax[1]=7.5 GHzRangeMin[1]=5.5 GHzRangeVar[1]="freq"Weight=Max=-18Min=SimInstanceName="SP1"Expr="matching"

GOAL

GoalOptimGoal2

RangeMax[1]=7.5 GHzRangeMin[1]=5.5 GHzRangeVar[1]="freq"Weight=Max=Min=-0.2SimInstanceName="SP1"Expr="insertion_loss"

GOAL

OptimOptim1

SaveCurrentEF=noUseAllGoals=yes

UseAllOptVars=yesSaveAllIterations=noSaveNominal=yesUpdateDataset=yesSaveOptimVars=noSaveGoals=yesSaveSolns=noSeed= SetBestValues=yesNormalizeGoals=noFinalAnalysis="SP1"StatusLevel=4DesiredError=0.0MaxIters=25OptimType=Random

OPTIM

MLINTL10

L=L4W=3586.240000 umSubst="MSub3"

MLSCTL4

L=L3W=262 umSubst="MSub3"

MLINTL9

L=L2W=396.160000 umSubst="MSub3"

MLINTL8

L=L1W=178.873000 umSubst="MSub3"

MeasEqnMeas1

insertion_loss=dB(S(2,1))matching=dB(S(1,1))

EqnMeas

MTEETee1

W3=262.0 umW2=0.39616 mmW1=0.178873 mmSubst="MSub3"

MSTEPStep1

W2=3586.24 umW1=396.16 umSubst="MSub3"

MSUBMSub3

Rough=0 milTanD=9e-4 T=0.689 milHu=3.9e+34 milCond=5.8e7 Mur=1.0 Er=2.17 H=10.0 mil

MSub

TermTerm2

Z=50 OhmNum=2

S_ParamSP1

Step=10 MHzStop=9 GHzStart=4 GHz

S-PARAMETERS

LLe

R=L=0.52 nH

CCeC=0.62 pF

TermTerm1

Z=15.2 OhmNum=1

Page 51: IMPEDANCE TRANSFORMERS  AND  TAPERS

Design and Analysis of RF and Microwave SystemsEuropean Master of Researchon Information TechnologyEuropean Master of Researchon Information Technology

LEVY NETWORK EXAMPLE (10):ADS SIMULATION: optimization

5 6 7 84 9

-20

-15

-10

-5

-25

0

freq, GHz

dB(S

(1,1

))dB

(S(2

,1))

dB(le

vy3_

amb_

T_o

ptim

..S(1

,1))

dB(le

vy3_

amb_

T_o

ptim

..S(2

,1))

5.0 5.5 6.0 6.5 7.0 7.5 8.04.5 8.5

-0.8

-0.6

-0.4

-0.2

0.0

-1.0

0.2

freq, GHzdB

(S(2

,1))

dB(le

vy3_

amb_

T_o

ptim

..S(2

,1))