LTCC VCO Design Study

The Chinese University of Hong KongDepartment of Electronic Engineering

Ke-Li Wu (www.ee.cuhk.edu.hk/~klwu)

S.H. Cheng, K.K. M. Cheng, and K.-L. WuS.H. Cheng, K.K. M. Cheng, and K.S.H. Cheng, K.K. M. Cheng, and K.--L. WuL. Wu

LTCC VCO Design Studies LTCC VCO Design Studies

Department of Electronic EngineeringDepartment of Electronic EngineeringThe Chinese University of Hong KongThe Chinese University of Hong Kong



1. Introduction1. . IntroductionIntroduction

2. Theory of oscillator design22. . Theory of oscillator designTheory of oscillator design

3. Noise in oscillators33. . Noise in oscillatorsNoise in oscillators

4. High-Q LTCC resonator design4. 4. HighHigh--Q LTCC resonator designQ LTCC resonator design

5. LTCC VCO design5. 5. LTCC VCO designLTCC VCO design

6. Experimental result6. 6. Experimental resultExperimental result

7. Conclusion7. 7. ConclusionConclusion

ContentsContents



1. LTCC VCO design1. LTCC VCO design

LTCC VCO design

LTCC VCO design procedure:LTCC VCO design procedure:

VCO circuit design

VCO circuit design

LTCC element realization

LTCC element realization

LTCC VCO integration and VCO simulation

LTCC VCO integration and VCO simulation

Circuit fabrication

Circuit fabrication

Performance evaluation

Performance evaluation

LTCC layoutoptimizationLTCC layoutoptimization



Theory of oscillator design

ZL

C1C3

C2L

ZL

C1C3

C2L

Two possible placements of the frequency tuning component.Two possible placements of the frequency tuning component.



Theory of oscillator design

Two-port active device networkResonator

Load network

ZL

ZR ZIN

Port 1 Port 2

RR RIN

jXR jXIN

1>ΓΓ INR 1>ΓΓ INR

Oscillation start up condition:Oscillation start up condition:

Steady state oscillation condition:Steady state oscillation condition:

1=ΓΓ INR 1=ΓΓ INR 1=ΓΓ OUTL 1=ΓΓ OUTLifif

ZIN + ZL = 0ZIN + ZL = 0

⇒⇒



Noise in oscillator

+

+

+= 2

22

2

212

1121log10)(

m

venr

m

c

SL

o

mm f

KkTRff

PFkTB

Qf

ffL

+

+

+= 2

22

2

212

1121log10)(

m

venr

m

c

SL

o

mm f

KkTRff

PFkTB

Qf

ffL

VCO phase noise:VCO phase noise:

Renv – effective noise resistance of the varactorKv – VCO gain in Hz/VRenv – effective noise resistance of the varactorKv – VCO gain in Hz/V

1. Choose an active device with the lowest possible flicker corner frequency (fc). Minimizes flicker noise using proper circuit design techniques.

2. Select a varactor having a lower effective noise resistance.3. Increase the loaded Q (QL) of the oscillator. It can be achieved

by using components with higher unloaded Q (Qu).

1. Choose an active device with the lowest possible flicker corner frequency (fc). Minimizes flicker noise using proper circuit design techniques.

2. Select a varactor having a lower effective noise resistance.3. Increase the loaded Q (QL) of the oscillator. It can be achieved

by using components with higher unloaded Q (Qu).

fo – center frequencyfm – offset frequency from the carrierfc – device flicker noise corner frequencyQL – loaded Q-factor of the resonance tankPS – signal levelF – device noise figurekTB – constant equals –174dBm/Hz with a 1 Hz bandwidth

fo – center frequencyfm – offset frequency from the carrierfc – device flicker noise corner frequencyQL – loaded Q-factor of the resonance tankPS – signal levelF – device noise figurekTB – constant equals –174dBm/Hz with a 1 Hz bandwidth



HBFP0450

Select a suitable transistorSelect a suitable transistorVCC

RFC

RB1RB2

RE

RC

RFCBiasing circuit designBiasing circuit design

CR

LR

Oscillator circuit completionOscillator circuit completion

Output filter

C2

50Ω

DC blockNegative resistance designNegative resistance design

Cf

Cb

CvRFC

VCtrl

Frequency tuning network designFrequency tuning network design

VCO circuit schematic designVCO circuit schematic design

LTCC VCO design



TermTerm1

Z=50 OhmNum=1

DC_BlockDC_Block1

TermTerm2

Z=50 OhmNum=2

LL39

R=1 OhmL=5.9 nH

CC57C=1 pF

LL38

R=L=4 nH

LL37

R=L=4 nH

CC53C=3 pF

CC52C=3 pF

CC51C=3 pF

di_sms_bb833_19930908D1

mb_mrt_LQG_11A_19970328L28PART_NUM=LQG11A27NJ00 27nH

RR3R=3.6 kOhm

RR2R=3.6 kOhm

RR7R=68 Ohm


mb_mrt_GRM_39_19950721C50PART_NUM=GRM39C0G040C50 4.0pF

RR1R=50 Ohm

V_DCSRC1Vdc=3 V


V_DCSRC2Vdc=Vin V

CC55C=1.5 pF

CC54C=1.8 pF

pb_hp_HBFP0450_19980529Q5

CC56C=5 pF


TermTerm1

Z=50 OhmNum=1

DC_BlockDC_Block1

TermTerm2

Z=50 OhmNum=2

LL39

R=1 OhmL=5.9 nH

CC57C=1 pF

LL38

R=L=4 nH

LL37

R=L=4 nH

CC53C=3 pF

CC52C=3 pF

CC51C=3 pF

di_sms_bb833_19930908D1


RR3R=3.6 kOhm

RR2R=3.6 kOhm

RR7R=68 Ohm



RR1R=50 Ohm

V_DCSRC1Vdc=3 V


V_DCSRC2Vdc=Vin V

CC55C=1.5 pF

CC54C=1.8 pF

pb_hp_HBFP0450_19980529Q5

CC56C=5 pF


LTCC VCO design



2.05 2.10 2.15 2.20 2.25 2.30 2.352.00 2.40

-50

0

50

-100

100

freq, GHz

phas

e(Z

(2,2

))m

ag(Z

(2,2

))

2.05 2.10 2.15 2.20 2.25 2.30 2.352.00 2.40

-50

0

50

-100

100

freq, GHz

phas

e(Z

(2,2

))m

ag(Z

(2,2

))

2.05 2.10 2.15 2.20 2.25 2.30 2.352.00 2.40

-16

-14

-12

-10

-8

-6

-18

-4

freq, GHz

real

(Z(1

,1))

2.05 2.10 2.15 2.20 2.25 2.30 2.352.00 2.40

-16

-14

-12

-10

-8

-6

-18

-4

freq, GHz

real

(Z(1

,1))

Vctrl = 3VVctrl = 3V

Vctrl = 0VVctrl = 0V

m1freq=2.289GHzVin=0.000000imag(Z(1,1))+imag(Z(2,2))=0.043


2.28 2.30 2.32 2.342.26 2.36

-10

-5

0

5

-15

10

freq, GHz

imag

(Z(1

,1))

+im

ag(Z

(2,2

))

m1 m2

real

(Z(1

,1))

+re

al(Z

(2,2

))



2.28 2.30 2.32 2.342.26 2.36

-10

-5

0

5

-15

10

freq, GHz

imag

(Z(1

,1))

+im

ag(Z

(2,2

))

m1 m2

real

(Z(1

,1))

+re

al(Z

(2,2

))

LTCC VCO design



OscPortOsc1

MaxLoopGainStep=FundIndex=1Steps=10NumOctav es=2Z=1.1 OhmV=

CC57C=1 pF

LL39

R=1 OhmL=5.9 nH

LL38

R=L=4 nH

LL37

R=L=4 nH

CC53C=3 pF

CC52C=3 pF

CC51C=3 pF

di_sms_bb833_19930908D1


RR3R=3.6 kOhm

RR2R=3.6 kOhm

RR7R=68 Ohm



RR1R=50 Ohm

V_DCSRC1Vdc=3 V


V_DCSRC2Vdc=Vin V

CC55C=1.5 pF

CC54C=1.8 pF

pb_hp_HBFP0450_19980529Q5

CC56C=5 pF


OscPortOsc1

MaxLoopGainStep=FundIndex=1Steps=10NumOctav es=2Z=1.1 OhmV=

CC57C=1 pF

LL39

R=1 OhmL=5.9 nH

LL38

R=L=4 nH

LL37

R=L=4 nH

CC53C=3 pF

CC52C=3 pF

CC51C=3 pF

di_sms_bb833_19930908D1


RR3R=3.6 kOhm

RR2R=3.6 kOhm

RR7R=68 Ohm



RR1R=50 Ohm

V_DCSRC1Vdc=3 V


V_DCSRC2Vdc=Vin V

CC55C=1.5 pF

CC54C=1.8 pF

pb_hp_HBFP0450_19980529Q5

CC56C=5 pF


LTCC VCO design

Harmonic Balance Simulation



m3noisefreq=1.000kHzVin=0.000000pnfm=-82.628



m6noisefreq=1.000MHzVin=0.000000pnfm=-142.628

1E4 1E5 1E61E3 1E7

-160

-140

-120

-100

-80

-180

-60

noisefreq, Hz

pnfm

, dB

c

m3

m4

m5

m6





1E4 1E5 1E61E3 1E7

-160

-140

-120

-100

-80

-180

-60

noisefreq, Hz

pnfm

, dB

c

m3

m4

m5

m6

0.5 1.0 1.5 2.0 2.50.0 3.0

2.33

2.34

2.35

2.36

2.37

2.32

2.38

HB.Vin

HB

.freq

[::, 1

], G

Hz

0.5 1.0 1.5 2.0 2.50.0 3.0

2.33

2.34

2.35

2.36

2.37

2.32

2.38

HB.Vin

HB

.freq

[::, 1

], G

Hz

0.5 1.0 1.5 2.0 2.50.0 3.0

8.4

8.6

8.8

9.0

8.2

9.2

HB.Vin

dBm

(HB

.Vou

t[::,1

])

0.5 1.0 1.5 2.0 2.50.0 3.0

8.4

8.6

8.8

9.0

8.2

9.2

HB.Vin

dBm

(HB

.Vou

t[::,1

])LTCC VCO design



CR

LR

Output filter

C2

Cf

Cb

HBFP0450

VCC

RFC

RB1RB2

RE

RC

RFC

50Ω

DC block

CvRFC

VCtrl

Striplineresonator

Outputfilter

Feedback network

LTCC substrate

CR

LR

Output filter

C2

Cf

Cb

LTCC VCO design



CC3C=3 pF

CC2C=3 pF

CC1C=3 pF

LL2

R=L=4 nH

LL1

R=L=4 nH

PortP2Num=2

PortP1Num=1


CC3C=3 pF

CC2C=3 pF

CC1C=3 pF

LL2

R=L=4 nH

LL1

R=L=4 nH

PortP2Num=2

PortP1Num=1


LTCC element realization: Output filter designLTCC element realization: Output filter design

LTCC VCO design



Ground plane is not shown

2.5 3.0 3.5 4.0 4.52.0 5.0

-40

-30

-20

-10

-50

0

freq, GHz

dB(S

(2,1

))

2.5 3.0 3.5 4.0 4.52.0 5.0

-40

-30

-20

-10

-50

0

freq, GHz

dB(S

(2,1

))

LTCC VCO design



LTCC element realization: feedaback network designLTCC element realization: feedaback network design

CC3C=0.01349 pF

PortP2Num=2

CC1C=4.868 pF

PortP1Num=1

CC2C=1.496 pF

CC3C=0.01349 pF

PortP2Num=2

CC1C=4.868 pF

PortP1Num=1

CC2C=1.496 pF

LTCC VCO design



High-Q LTCC resonator

Laminated stripline resonator designLaminated stripline resonator design

w

hh

λ/4

Stripine thickness = t

εr

g

Vertical structure:Vertical structure:- 15 layers- each layer thickness = 3.6mils- via-diameter = 5.2mils

- 15 layers- each layer thickness = 3.6mils- via-diameter = 5.2mils

LTCC material properties:LTCC material properties:- DuPont 6145D- εr = 7.8- lost tangent = 0.002

- DuPont 6145D- εr = 7.8- lost tangent = 0.002

Dimension:Dimension:- l = λ/4 = 441mils- l = λ/4 = 441mils



Resonator layout and simulation resultResonator layout and simulation result

fo

Reflection curve of the resonatorReflection curve of the resonator




From the simulation result obtained, the Q can be calculated byFrom the simulation result obtained, the Q can be calculated by

oww

o

ddQ

=

=ωφω

2oww

o

ddQ

=

=ωφω

2

where φ is the phase angle of the z-parameter which change with frequencywhere φ is the phase angle of the z-parameter which change with frequency




Top and bottom ground planes are removed

Stripline

Shielding

Measurement port

1. Traditional Stripline1. Traditional Stripline




Stripline – resonant frequencyStripline – resonant frequency

2.16

2.18

2.2

2.22

2.24

2.26

2.28

8 10 12 14 16 18 20 22 24 26Line width (mils)

Res

onan

t fre

quen

cy (G

Hz)

h = 21.6 milsh = 28.8 milsh = 36 milsh = 43.2 mils




Stripline – unloaded QStripline – unloaded Q

100

110

120

130

140

150

160

170

8 10 12 14 16 18 20 22 24 26Line width (mils)

Res

onat

or u

nloa

ded

Q

h = 21.6 milsh = 28.8 milsh = 36 milsh = 43.2 mils




2. Meander-line stripline resonator2. Meander-line stripline resonator


Meander lineShielding Measurement port




12 mils50 mils

50 mils

50 mils

280 mils

292 mils

50 mils

50 mils132 mils

561 mils

12 mils




Stripline versus Meander-line – resonant frequencyStripline versus Meander-line – resonant frequency

2.15

2.2

2.25

2.3

2.35

2.4

2.45

2.5

2.55

2.6

12 14 16 18 20 22 24 26Line width (mils)

Res

onan

t fre

quen

cy (G

Hz)

meander-line stripline

Stripline




Stripline versus Meander-line – unloaded QStripline versus Meander-line – unloaded Q

140

145

150

155

160

165

170

12 14 16 18 20 22 24 26Line width (mils)

Res

onat

or u

nloa

ded

Q

meander-line stripline

Stripline





Bi-metal-layer stripline

Shielding

Measurement port

3. Bi-metal-layer stripline resonator3. Bi-metal-layer stripline resonator

Bi-metal layer stripline

Ground planes

Vias sidewall




Stripline versus Bi-metal-layer stripline – resonant frequencyStripline versus Bi-metal-layer stripline – resonant frequency

2.14

2.16

2.18

2.2

2.22

2.24

2.26

2.28

8 10 12 14 16 18 20 22 24 26

Line width (mils)

Res

onan

t fre

quen

cy (G

Hz)

Stripline

Bi-metal layer




Stripline versus Bi-metal-layer stripline – unloaded QStripline versus Bi-metal-layer stripline – unloaded Q

120

130

140

150

160

170

180

8 10 12 14 16 18 20 22 24 26Line width (mils)

Res

onat

or u

nloa

ded

Q

Stripline

Bi-metal layer




LTCC element realization: Resonator designLTCC element realization: Resonator design

2.05 2.10 2.15 2.20 2.25 2.30 2.352.00 2.40

-50

0

50

-100

100

freq, GHz

phas

e(Z

(1,1

))ph

ase(

Z(2

,2))

2.05 2.10 2.15 2.20 2.25 2.30 2.352.00 2.40

-50

0

50

-100

100

freq, GHz

phas

e(Z

(1,1

))ph

ase(

Z(2

,2))

self-resonant frequency 2.052 GHzunloaded Q = 90.3144self-resonant frequency 2.052 GHzunloaded Q = 90.3144




LTCC layout integration and VCO simulationLTCC layout integration and VCO simulation

ResonatorResonator

Output filterOutput filter

Output portOutput port

C2 and CfnetworkC2 and Cfnetwork

CbCbTop-partTop-part

Bottom-partBottom-part

LTCC VCO design



Vc

Vb

Ve

VeVe

Vout

Vmain

pb_hp_HBFP0450_19980529Q5

DC_BlockDC_Block8

OscPortOsc1

MaxLoopGainStep=FundIndex=1Steps=10NumOctaves=2Z=1.1 OhmV=

DC_BlockDC_Block10


RR2R=3.6 kOhm

RR3R=3.6 kOhm


DC_BlockDC_Block11

DC_BlockDC_Block12

RR1R=50 Ohm


di_sms_bb833_19930908D1 V_DC

SRC2Vdc=Vin V


S6PSNP5File="D:\tonytemp\Thesis_sim\vco\VCOtest05_3646ce_3646cbe_3666cres_matching1_new.sp"

1 5

4

6

3 Re f2

DC_BlockDC_Block7


RR7R=68 Ohm

V_DCSRC1Vdc=3 V

Vc

Vb

Ve

VeVe

Vout

Vmain

pb_hp_HBFP0450_19980529Q5

DC_BlockDC_Block8

OscPortOsc1

MaxLoopGainStep=FundIndex=1Steps=10NumOctaves=2Z=1.1 OhmV=

DC_BlockDC_Block10


RR2R=3.6 kOhm

RR3R=3.6 kOhm


DC_BlockDC_Block11

DC_BlockDC_Block12

RR1R=50 Ohm


di_sms_bb833_19930908D1 V_DC

SRC2Vdc=Vin V


S6PSNP5File="D:\tonytemp\Thesis_sim\vco\VCOtest05_3646ce_3646cbe_3666cres_matching1_new.sp"

1 5

4

6

3 Re f2

DC_BlockDC_Block7


RR7R=68 Ohm

V_DCSRC1Vdc=3 V

LTCC VCO design

Design verificationDesign verification







1E4 1E5 1E61E3 1E7

-160

-140

-120

-100

-80

-180

-60

noisefreq, Hzpn

fm, d

Bc

m3

m4

m5

m6





1E4 1E5 1E61E3 1E7

-160

-140

-120

-100

-80

-180

-60

noisefreq, Hzpn

fm, d

Bc

m3

m4

m5

m6

0.5 1.0 1.5 2.0 2.50.0 3.0

2.18

2.20

2.22

2.24

2.26

2.16

2.28

HB.Vin

HB

.freq

[::,

1], G

Hz

0.5 1.0 1.5 2.0 2.50.0 3.0

2.18

2.20

2.22

2.24

2.26

2.16

2.28

HB.Vin

HB

.freq

[::,

1], G

Hz

0.5 1.0 1.5 2.0 2.50.0 3.0

-4

-3

-2

-5

-1

HB.Vin

dBm

(HB

.Vou

t[::,1

])

0.5 1.0 1.5 2.0 2.50.0 3.0

-4

-3

-2

-5

-1

HB.Vin

dBm

(HB

.Vou

t[::,1

])LTCC VCO design



Circuit layout

LTCC VCO design



Measurement setupMeasurement setup

Network analyzerNetwork analyzer

Measurement control unitMeasurement control unit Probe stationProbe station

Experimental resultExperimental result

LTCC VCO design



Biasing resistorBiasing resistor

BJT HBFP0450BJT HBFP0450

Varactor BB833Varactor BB833RFCRFC

DC blockDC block

GNDGND

VccVcc

VctrlVctrl

Output portOutput port

VCO measurement setup and resultVCO measurement setup and result

VCO analyzerVCO analyzer

LTCC VCO design



-70

-60

-50

-40

-30

-20

-10

0

10

2 2.4375 2.875 3.3125 3.75 4.1875 4.625 5.0625 5.5

Oscillation frequency (GHz)

Out

put p

ower

(dB

m)

-70

-60

-50

-40

-30

-20

-10

0

10

2 2.4375 2.875 3.3125 3.75 4.1875 4.625 5.0625 5.5


Out

put p

ower

(dB

m)

0 dBm0 dBm

-50.37 dBm-50.37 dBm

Output spectrumOutput spectrum

2.3592GHz @ Vin = 3V2.3592GHz @ Vin = 3V

-80.00

-60.00

-40.00

-20.00

0.00

20.00

2.3587 2.3589 2.3591 2.3593 2.3595 2.3597 2.3599


Out

put p

ower

(dB

m)

-80.00

-60.00

-40.00

-20.00

0.00

20.00

2.3587 2.3589 2.3591 2.3593 2.3595 2.3597 2.3599


Out

put p

ower

(dB

m)

LTCC VCO design



2.28

2.29

2.3

2.31

2.32

2.33

2.34

2.35

2.36

2.37

0 0.5 1 1.5 2 2.5 3

Control voltage (V)

Osc

illat

ion

freq

uenc

y (G

Hz)

2.28

2.29

2.3

2.31

2.32

2.33

2.34

2.35

2.36

2.37

0 0.5 1 1.5 2 2.5 3

Control voltage (V)

Osc

illat

ion

freq

uenc

y (G

Hz)

-8

-7

-6

-5

-4

-3

-2

-1

0

0 0.5 1 1.5 2 2.5 3

Control voltage (V)

Out

put p

ower

(dB

m)

-8

-7

-6

-5

-4

-3

-2

-1

0

0 0.5 1 1.5 2 2.5 3

Control voltage (V)

Out

put p

ower

(dB

m)

VCO tuning characteristicsVCO tuning characteristics

LTCC VCO design



-160

-140

-120

-100

-80

-60

-40

1 10 100 1000 10000

Offset frequency (kHz)

Phas

e no

ise

(dB

c/H

z)

-160

-140

-120

-100

-80

-60

-40

1 10 100 1000 10000

Offset frequency (kHz)

Phas

e no

ise

(dB

c/H

z)

-120.86 dBc/Hz-120.86 dBc/Hz

Phase noise performancePhase noise performance

LTCC VCO design

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LTCC VCO Design Study

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