ims’05 workshop-wmbhome.eps.hw.ac.uk/~ceejh3/presentations/microstrip... · 12 dr. jia-sheng hong...

1

Dr. JiaDr. Jia--Sheng Hong Sheng Hong Department of Electrical, Electronic and Computer EngineeringDepartment of Electrical, Electronic and Computer EngineeringHeriotHeriot--Watt University, UKWatt University, [email protected]@hw.ac.uk

Practical Aspects of Microwave Filter Design and RealizationIMS’05 Workshop-WMB

Microstrip Filter DesignMicrostrip Filter Design

JiaJia--Sheng HongSheng HongHeriot-Watt University

Edinburgh, [email protected]@hw.ac.uk

2


OutlineOutline

Introduction Introduction

Design considerationsDesign considerations

Design examples Design examples

SummarySummary

3


IntroductionIntroduction-- Driving forcesDriving forces

Recent development of microstrip filters has been driven by applications -

Wireless communications Wireless communications

Wireless sensor/radar systemsWireless sensor/radar systems

………….. Driven by technologies -

High temperature superconducting High temperature superconducting

Micromachining Micromachining

LTCC LTCC

FerroelectricFerroelectric

…………. .

4


IntroductionIntroduction-- Microstrip Filter PublicationsMicrostrip Filter Publications

0

20

40

60

80

100

120

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004

Search from IEEE Search from IEEE XploreXplore

Total 600+ in recent 10 yearsTotal 600+ in recent 10 years

Year

Number

5


Design ConsiderationsDesign Considerations-- TopologiesTopologies

l2l1 l3 l5

WC

WL

l7

l4 l6

L3

L4

L5

C4

C6L1

L2

C2

Z0 Z0

W1

l1 lnl2 ln+1

W1

Wn+1

Wn+1

Y0

Y0

s1

sn+1

s2

sn

W2

Wn

W2

Wn

Yt YtY1

s1,2 sn-1,n

qt

l1 l2 l3 ln

s2,3

W1 W2 W3 Wn

Yn

YA

q01

YA

CL1 CL2 CL3 CLnCLn-1

0 2 3 n n+1n-1

~ /4λ

Via hole grounding

~ /4λ

l g0/4 l g0/4

s1

s2

s3

s4

s5

l1h l5hl2h l3h l4h

l1v l3v l5v

l2v l4v

W

~/4λ

~ /4λ

6


Design ConsiderationsDesign Considerations-- TopologiesTopologies

The choice of a topology depends onThe choice of a topology depends on

Characteristics of filters, such as chebyshev or elliptic BandwidthSizePower handling

7


Design ConsiderationsDesign Considerations-- SubstratesSubstrates

SizeHigher-order modesSurface wave effects Implementations – couplings, line/spacing tolerances, …

Dielectric lossTemperature stabilityPower handling – dielectric strength (breakdown), thermal conductivity

The choice of a The choice of a substrate depends onsubstrate depends on

8


Design ConsiderationsDesign Considerations-- HigherHigher--order modesorder modes

Keep operating frequencies below the cutoff frequency of the 1st higher-order mode,

( )hWcf

rc 8.02 +

=ε

Substrate thickness h (mm)

0.2 0.4 0.6 0.8 1.0 1.2 1.4

Cut

off f

requ

ency

fc

(GH

z)

20

30

40

50

60

70

80

90

εr = 3

εr = 6.15

εr = 10.8

W = 1.0 mm


0.2 0.4 0.6 0.8 1.0 1.2 1.4

Cut

off f

requ

ency

fc

(GH

z)10

20

30

40

50

60

70

80

90

W=0.5 mmW=1.0 mmW=1.5 mm

εr = 10.8

9


Design ConsiderationsDesign Considerations-- Surface wavesSurface waves

Keep operating frequencies below the threat frequency of the lowest surface wave mode,

12tan 1

−=

−

r

rs h

cfεπ

ε


0.2 0.4 0.6 0.8 1.0 1.2 1.4

Thre

at fr

eque

ncy

f s (G

Hz)

0

100

200

300

400

500

600

700

εr = 3

εr = 6.15

εr = 10.8at which the surface mode couples strongly to the dominant mode of microstrip because the phase velocities of the two modes are close.

10


Design ConsiderationsDesign Considerations-- LossesLosses

There are three major losses in a microstrip resonator:

⎟⎟⎠

⎞⎜⎜⎝

⎛ Ω⋅⎟

⎠⎞

⎜⎝⎛∝

sc R

hQ 377λ

π

δtan1

∝dQ

Conductor loss

Dielectric loss

Radiation loss

rdcu QQQQ1111

++=

11


Design ConsiderationsDesign Considerations-- Power handlingPower handling

Peak power handling capability –when the breakdown occurs in substrate

c

op Z

VP2

2

∝

Vo is the maximum breakdown voltage of the substrate

Zc is the characteristic impedance of the microstrip

Narrower band filters result in higher electric field density, Narrower band filters result in higher electric field density, leading to a lower peak power handlingleading to a lower peak power handling

12


Design ConsiderationsDesign Considerations-- TemperatureTemperature effecteffectTemperature characteristic of a microstrip half-wavelength resonator on

RT/Duroid substrate with εr = 10.2, h = 1.27 mm

Copper CTECopper CTE (coefficient of thermal expansion) = 17 ppm/oCSubstrate CTESubstrate CTE = 24 ppm/oCSubstrate TCKSubstrate TCK (thermal coefficient of εr) = −425 ppm/oCAt 23 oC f0 = 1929.8 MHz ∆f = 0

At 73 oC for copper CTE only f0 = 1928.1 MHz ∆f = −1.7 MHz

At 73 oC for substrate thickness CTE only f0 = 1929.9 MHz ∆f = 0.1 MHz

At 73 oC for substrate TCK only f0 = 1949.4 MHz ∆f = 19.6 MHz

At 73 oC (consider all) f0 = 1947.8 MHz ∆f = 18.0 MHz

Frequency variation versus temperature is mainly due to Frequency variation versus temperature is mainly due to dielectric constant change dielectric constant change vsvs temperaturetemperature

13


Design ExamplesDesign Examples-- OpenOpen--loop filtersloop filters

( )c ( )d

( )a ( )b

1

11

2

2

2

3

33

4

4

4

5

5

6

6

7 81

2 3

4 5

6 7

8

From: Jia-Sheng Hong and M.J.Lancaster, Microstrip Filters for RF/Microwave Applications,

John Wiley & Sons. Inc. New York, 2001

14



Specifications:Specifications:Center frequency 985MHz

Fractional Bandwidth 10.359%

40dB-Rejection Bandwidth 125.5MHz

Passband Return loss −20dB

Design parameters for an 8Design parameters for an 8--pole filter:pole filter:

92027.9 01752.00723.0 05375.0

06063.0 08441.0

6,3

5,46,54,3

7,63,28,72,1

==−=

===

====

eoei QQMMMM

MMMM


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Frequency (MHz)

925 950 975 1000 1025 1050

Inse

rtion

/Ret

urn

Loss

(dB

)

-40

-35

-30

-25

-20

-15

-10

-5

0

Insertion lossReturn loss

Frequency (MHz)

600 800 1000 1200 1400

Inse

rtion

Los

s (d

B)

-80

-60

-40

-20

0

Realisation 1Realisation 1On RT/Duroid substrate with a relative dielectric constant of 10.8 and a thickness of 1.27mm. Each resonator has a size of 16 by 16 mm.

16



Realisation 2Realisation 2

On RT/Duroid substrate with a relative dielectric constant of 10.8 and a thickness of 1.27mm

17


Design ExamplesDesign Examples-- Trisection openTrisection open--loop filtersloop filters

On RT/On RT/DuroidDuroid substrate with a relative dielectric substrate with a relative dielectric constant of 10.8 and a thickness of 1.27mmconstant of 10.8 and a thickness of 1.27mm

Frequency (MHz)

700 750 800 850 900 950 1000 1050 1100

Mag

nitu

de (d

B)

-50

-40

-30

-20

-10

0

S21

S11

02907.004753.0

7203.15MHz 713.914

MHz 471.899

13

2312

02

0301

−===

===

==

MMM

QQf

ff

eoei

Midband or centre frequency : 905MHz

Bandwidth of pass band : 40MHz

Return loss in the pass band : < −20dB

Rejection : > 20dB for frequencies ≥ 950MHz

Measured responseMeasured response

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On RT/On RT/DuroidDuroid substrate with a relative dielectric substrate with a relative dielectric constant of 10.8 and a thickness of 1.27mmconstant of 10.8 and a thickness of 1.27mm

Frequency (MHz)

700 750 800 850 900 950 1000 1050 1100M

agni

tude

(dB)

-60

-50

-40

-30

-20

-10

0

S21

S11

Midband or centre frequency : 910MHz

Bandwidth of pass band : 40MHz

Return loss in the pass band : < −20dB

Rejection : > 35dB for frequencies ≤ 843MHz01915.0

05641.06698.14MHz 734.905

MHz 159.916

13

2312

02

0301

===

===

==

MMM

QQf

ff

eoei

Measured responseMeasured response

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Frequency (GHz)

0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5

Inse

rtion

Los

s (d

B)

-80

-60

-40

-20

0

Measured wideband responseMeasured wideband response

Frequency (MHz)

200 400 600 800 1000 1200

Inse

rtion

Los

s (d

B)

-80

-60

-40

-20

0

case 1case 2case 3case 4

Experimental results on extra Experimental results on extra transmission zeros, where case 1 to 4 transmission zeros, where case 1 to 4 indicate the increase of direct coupling indicate the increase of direct coupling between the two feed lines. between the two feed lines.

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Design ExamplesDesign Examples-- MultiMulti--layer filterslayer filters

Magnetic CouplingApertureElectric

CouplingAperture

MicrostripOpen-LoopResonator

CommonGroundPlane

DielectricSubstrate

I/O Ports

21



Frequency (MHz)

850 900 950 1000 1050 1100

Tran

smis

sion

/Ret

urn

Loss

(dB)

-60

-50

-40

-30

-20

-10

0

Qu=200

ChebyshevElliptic

Linear Phase

(a)

Frequency (MHz)

940 950 960 970 980 990

Gro

up D

elay

(ns)

0

5

10

15

20

25

30

35

ChebyshevEllipticLinear Phase

Qu=200

(b)

22



Frequency (MHz)

850 900 950 1000 1050 1100

Tran

smis

sion

(dB)

-60

-50

-40

-30

-20

-10

0

Frequency (MHz)

940 950 960 970 980 990 1000

Gro

up d

elay

(ns)

0

10

20

30

40Frequency (MHz)

850 900 950 1000 1050 1100

Tran

smis

sion

(dB)

-60

-50

-40

-30

-20

-10

0

Frequency (MHz)

940 950 960 970 980 990 1000

Gro

up d

elay

(ns)

0

10

20

30

40

(a) (b)

Frequency (MHz)

850 900 950 1000 1050 1100

Tran

smis

sion

(dB)

-60

-50

-40

-30

-20

-10

0

Frequency (MHz)

940 950 960 970 980 990 1000

Gro

up d

elay

(ns)

0

10

20

30

40

(c)

Experimental resultsExperimental results

23


Design ExamplesDesign Examples-- SlowSlow--wave filterswave filters

d

L1

wa

w1L2

w2

Open-stub length, L (mm)

0 1 2 3 4 5 6 7 8 9 10 11

Freq

uenc

y (G

Hz)

0

1

2

3

4

5

6

7

f 1 /

f 0

1.50

1.75

2.00

2.25

2.50

2.75

3.00

3.25f0f1f1 / f0

Wa=1 mm, w1=2 mm, w2=3 mm, d=16 mm on RT/Duroid 6010

d

C /2L C /2L

Z , a ab

V1 V2

I1 I2

Loading capacitance (pf)

0 1 2 3 4 5 6

Freq

uenc

y (G

Hz)

0

1

2

3

4

5

6

7

f 1 /

f 0

1.50

1.75

2.00

2.25

2.50

2.75

3.00

3.25f0f1f1 / f0

CapacitivelyCapacitively loaded line resonatorloaded line resonator Microstrip slow wave resonator (I)Microstrip slow wave resonator (I)

24


Design ExamplesDesign Examples-- SlowSlow--wave filterswave filtersCentre Frequency : 1335 MHz

3dB Bandwidth : 30 MHz

passband Loss : 3dB Max.

Min. stopband rejection :

D.C. to 1253 MHz 60dB

1457 to 2650 MHz 60dB

2650 to 3100 MHz 30dB

60dB Bandwidth : 200 MHz Max. On RT/Duroid 6010 substrate

25


Design ExamplesDesign Examples-- SlowSlow--wave filterswave filters

Frequency (GHz)

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5

Tran

smis

sion

(dB

)

-80

-60

-40

-20

0

Substrate: εr=10.8 h=1.27mm

37.75mm

0.5mm

26


Design ExamplesDesign Examples-- DualDual--mode filtersmode filters

( )a

( )c ( )d

( )b

( )e

20gD λ≈πλ 084.1 gD ≈

πλ 0gD ≈ 40gD λ≈40gD λ<

L2 C2L1C1

Mode 1 Mode 2

Type I dualType I dual--mode resonatormode resonator


Frequency (GHz)

1.3 1.4 1.5 1.6 1.7 1.8 1.9

Ampl

itude

(dB)

-50

-40

-30

-20

-10

0

S21

S11

16 mm

Port 1

Port 2

d x d

d =2 mm on RT/Duroid6010 substrate

2.5% bandwidth at 1.58 GHz

27


28



Port 1

Port 2

20 mm

1 mm

On RT/On RT/DuroidDuroid 6010 substrate6010 substrate Centred at 820 MHzCentred at 820 MHz

29



Type II dualType II dual--mode resonatormode resonator

⎟⎟⎠

⎞⎜⎜⎝

⎛2

,32

aa

⎟⎠

⎞⎜⎝

⎛ −2

,32

aa

⎟⎠

⎞⎜⎝

⎛− 0 ,3

a

a

XZ

Y

⎟⎟⎠

⎞⎜⎜⎝

⎛2

,32

aa

⎟⎠

⎞⎜⎝

⎛ −2

,32

aa

⎟⎠

⎞⎜⎝

⎛− 0 ,3

a

Equilateral triangular microstrip patch resonator

2 . 5

2.5

2

2

2

1 . 5

1 . 5

1.5

1

1

1

1

0.5

0.5

0 . 5

0

0

0

0.5

0.5

0.5

1

1

1

E

@ Mode 1

43.5

3

3

2.5

2.5

2

2

1.5

1.5

11

1

0.5

0.50.5

0.5

00

0

0

0

0

0.5 0.5

0.5

0.5

1

1

1.5

1.5

2

2

2.5

2.53

3.5 4

Ed

@ Mode 2

Electric Field PatternElectric Field Pattern

30



J0,2J2,3

J0,1

J0,3

J1,3

2

1

0 3

L2

L1

C2

C1

INPUT OUTPUT

a

w b

Circuit model (No coupling between the two modes)

Frequency (GHz)

3.0 3.5 4.0 4.5 5.0

Mag

nitu

de (d

B)

-50

-40

-30

-20

-10

0

|S11| (Theory)

|S21| (Theory)

|S11| (EM)

|S21| (EM)

(a = 15 mm and b = 11.25 mm on a 1.27mm thick dielectric substrate with a relative dielectric constant of 10.8)

Frequency response

31



Frequency (GHz)

2.8 3.2 3.6 4.0 4.4 4.8

Mag

nitu

de (d

B)

-70

-60

-50

-40

-30

-20

-10

0

10

|S11| (Theory)

|S21| (Theory)

|S11| (Simulation)

|S21| (Simulation)a

w b

a = 15 mm and b = 14 mm on a 1.27mm thick dielectric substrate with a relative dielectric constant of 10.8

Frequency response

32



FourFour--pole dualpole dual--mode filtersmode filters

On a substrate with a relative constant of 10.8 and a thickness of 1.27 mm

33


Design ExamplesDesign Examples-- DualDual--mode reject filtersmode reject filters

gW

a

s

l

1

2

PORT 1

Single dual-moderesonator

PORT 2

Frequency (GHz)

3.6 3.8 4.0 4.2 4.4

Mag

nitu

de (

dB)

-40

-30

-20

-10

0

S11

S21

The details to be presentedThe details to be presented in in another session (WE4C) at IMS2005another session (WE4C) at IMS2005

34


Design ExamplesDesign Examples-- ExtractExtract--pole filterspole filters

J=1 C=LsCs

L=Cs

Ls =zin zin

zin

l2

s

l1 g ≈λ /4

l3 g ≈λ /2


EM simulated performanceEM simulated performanceOn RT/On RT/DuroidDuroid 6010 substrate6010 substrate

35


36



On RT/On RT/DuroidDuroid 6010 substrate6010 substrate

37


Design ExamplesDesign Examples-- CQ filtersCQ filters

PORT 1 PORT 2

dB 0

-10

-20

-30

-40

-50

-60

-70

-80

-90

-100

8 pole 5MHz wideband S21 response 65KS21

Start: 1.880000 GHz Stop: 2.200000 GHz

Another 18Another 18--pole filter of this type with group delay equalisation will be pole filter of this type with group delay equalisation will be presentedpresented in TH1F session at IMS2005in TH1F session at IMS2005

38


Design ExamplesDesign Examples-- CQT filtersCQT filters

10PORT 1 PORT 2

dB

0dB

0

-10 -5

-20 -10

-30 -15

-40 -20

-50 -25

-60 -30

-70 -35

-80 -40

-90 -45

-100 -50

S11 S21

Start: 1.960000 GHz Stop: 1.985000 GHz

1

1 S21 1.974000 GHz-0.7590 dB

39


Design ExamplesDesign Examples-- Wideband filtersWideband filters

From: Jia-Sheng Hong and M.J.Lancaster, Microstrip Filters for RF/Microwave Applications,

John Wiley & Sons. Inc. New York, 2001

y1 y2 yn-1

y0=1

2θc

θc

yn

y1,2yn-1,n

Short-circuited stub of electrical length θc

y0=1

2θc

|S21

|

fc

θc π−θc θπ/2 3π/2π

f(π/θc −1)fc

Frequency (GHz)

0 1 2 3 4 5 6 7

Ampl

itude

(dB)

-60

-50

-40

-30

-20

-10

0

S21

S11

150

30

Via hole grounding

0.9 2.0 2.8

13.9 13.5 13.2

23.8 23.0 22.7

4.9

Unit: mm

On substrate: On substrate: εεrr = 2.2, h = 1.57 mm= 2.2, h = 1.57 mm

EM simulated performanceEM simulated performance

Optimum stub bandpass or pseudo Optimum stub bandpass or pseudo highpasshighpass

40


SummarySummaryMicrostrip filter designs involve a number of considerations, Microstrip filter designs involve a number of considerations, including careful choice of topologies and substrates. including careful choice of topologies and substrates. Some design examples of new topologies with advanced Some design examples of new topologies with advanced filtering characteristics have been described, including filtering characteristics have been described, including ––

OpenOpen--loop resonator filtersloop resonator filtersMultilayer filtersMultilayer filtersSlowSlow--wave filterswave filtersDualDual--mode filtersmode filtersExtract pole, Trisection, CQ and CQT filtersExtract pole, Trisection, CQ and CQT filtersOptimum wideband stub filtersOptimum wideband stub filters

Driven by applications and emerging device technologies, Driven by applications and emerging device technologies, many new and advanced microstrip filters have been many new and advanced microstrip filters have been developed and their designs are available in open literatures. developed and their designs are available in open literatures.

ims’05 workshop-wmbhome.eps.hw.ac.uk/~ceejh3/presentations/microstrip... · 12 dr. jia-sheng hong...

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