recent development in superconducting filtershome.eps.hw.ac.uk/~ceejh3/presentations/2006...

1

Dr. J.-S. Hong Department of Electrical, Electronic and Computer EngineeringHeriot-Watt University, UKEmail: [email protected]

Recent Development in Superconducting Filters

(Invited Talk)

Jia-Sheng Hong

Heriot-Watt University Edinburgh, UK

2


Outline

Introduction

HTS materials and substrates

Recent developed HTS Filters

Summary

3


Introduction

• The driving force behind the development of superconducting filters remains for mobile, satellite communications and some other niche applications.

• The extremely low resistance of superconducting materials has enabled the realization of miniature thin film filters with exceptional performances.

4


IntroductionIntroduction-- HTS Filter PublicationsHTS Filter Publications

05

101520253035404550

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

Search from IEEE Xplore

Total 260+ in recent 10 yearsTotal 260+ in recent 10 years

Year

Number

5


What is the Superconductor and HTS?What is the Superconductor and HTS?

Superconductors are materials which, when cooled below a certaintemperature, exhibit a zero intrinsic resistance to direct current (d.c.) flow.

The temperature at which the intrinsic resistance undergoes an abrupt change is referred to as the critical temperature or transition temperature (Tc).

The superconductors with transition temperature greater than 77 K, the boiling point of liquid nitrogen, are referred to as the high-temperature superconductors (HTS).

For alternating current (a.c.) flow, the surface resistance of the superconductor does not go to zero below Tc, but increases with increasing frequency.

6


HTS Materials HTS Materials

There are many hundreds of high-temperature superconductors with varying transition temperature Tc.

YBCO (yttium barium copper oxide) and TBCCO (thallium barium calcium copper oxide) are the two most popular and commercially available HTS materials.

Typical HTS materials

Materials TC (K)

YBa2Cu3O7-x (YBCO)

Tl2Ba2Ca1Cu2Ox (TBCCO)

≈92

≈105

7


Frequency (GHz)

1 10 100

Sur

face

Res

ista

nce

(mΩ

)

0.001

0.01

0.1

1

10

100

YBCO @77K

Cu @77K

Cu @300K

Surface Resistance of HTS Surface Resistance of HTS at RF/Microwave Frequenciesat RF/Microwave Frequencies

Micro ohms

8


HTS Thin Film TechnologyHTS Thin Film Technology

Devices can be patterned using wet or dry etching techniques, e.g.HTS thin films can be grown on a suitable

substrate using sputtering, laser ablation, or other thin film deposition techniques. HTS microstrip

Dielectric substrate

9


Substrates for HTS Thin FilmsSubstrates for HTS Thin Films

To obtain good quality film, the dimensions of crystalline lattice at the surface of the substrate should match that of lattice of HTS.

For RF applications the substrate should also have a low dielectric loss at RF.

There are three widely used substrates for growing HTS thin films for RF applications: Magnesium Oxide (MgO), Lanthanum Aluminate (LaAlO3), and Sapphire.

Substrates for HTS films

substrate rε (typical) δtan (typical)

LaAlO3 24.2 @ 77K 6106.7 −× @ 77K and 10 GHz

MgO 9.6 @ 77K 6105.5 −× @ 77K and 10 GHz

Sapphire 11.6 || c-axis @ 77K

9.4 ⊥ c-axis @ 77K

8105.1 −× @ 77K and 10 GHz

10


HTS filters for licensed frequency spectrum of mobile communications

Implement CQT (cascaded-quadruplet-trisection) or CQ designs for low insertion loss, high selectivity and/or linear group delay.

Implement HTS filters on sapphire wafers for low-cost

11


PLCID =r3L=l o3 nHC=co3 pF

TLINID= m34Z0=z34 OhmEL= 90 DegF0=F MHz

PLCID=r4L= lo4 nHC= co4 pF

TLINID=m45Z0=z45 OhmEL=90 DegF0=F MHz

PLCID=r1L= lo1 nHC= co 1 pF

TLINID= m12Z0= z12 Oh mEL =90 DegF0= F MHz

PLCID= r2L=lo 2 nHC=co2 pF

T LINID=m23Z 0=z23 OhmEL=9 0 DegF 0=F MHz

PL CID= r7L=lo7 nHC=co7 pF

TLINID=m78Z0=z78 OhmEL= 90 De gF0=F MHz

PLCID=r8L= lo8 nHC= co8 pF

TL INID=m89Z0 =z89 O hmEL=90 DegF0 =F MH z

PLCID=r5L=l o5 n HC=co5 pF

TLINID=m56Z0=z56 OhmEL= 90 D egF0=F MHz

PLCID= r6L=lo6 nHC=co6 pF

T LINID=m67Z 0=z67 O hmEL=90 DegF 0=F MHz


TLINID= m91 0Z0= z91 0 O hmEL =90 DegF0= F MHz


TLINID=zZ0=50 OhmEL=90 DegF0=F MHz

TLINID= z1Z0= 50 O hmEL =90 DegF0= F MHz

T LINID=M13Z 0=z13 OhmEL=-90 DegF 0=F MHz

TL INID=m47Z0 =z47 O hmEL=-90 DegF0 =F MH z

T LINID=m810Z 0=z810 OhmEL=90 DegF 0=F MHz

PORTP=1Z= 50 O hm

PORTP=2Z=50 Ohm

1010--pole CQT 10pole CQT 10--MHz HTS FilterMHz HTS FilterDesignDesign

10PORT 1 PORT 2

12


1010--pole CQT 10pole CQT 10--MHz HTS FilterMHz HTS FilterDesignDesign

1945 1950 1955 1960 1965

10 pole 10 MHz ideal

-100

-80

-60

-40

-20

0

S11

S21 M a g n i t u d e

(dB)

13


1010--pole CQT 10pole CQT 10--MHz HTS FilterMHz HTS FilterFabrication & packagingFabrication & packaging

•The designed filter was fabricated on a 0.43mm-thick sapphire wafer with double-sided YBCO films.

•The YBCO thin films have a thickness of 300 nm and a characteristic temperature of 87K.

•Both sides of the wafer are gold-plated with 200 nm thick gold (Au). The gold RF contacts are epoxy bonded to K-connectors with sliding contacts.

•The fabricated HTS filter used a wafer size of 47x17 mm.

14


1010--pole CQT 10pole CQT 10--MHz HTS FilterMHz HTS FilterMeasured performanceMeasured performance

dB 0

-10

-20

-30

-40

-50

-60

-70

-80

-90

-100

S21

Start: 1.880000 GHz Stop: 2.200000 GHz

1

1 S211.975000 GHz

-0.4885 dB

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

Excellent narrow-band response with a good rejection over the entire UMTS transmission band (2110 - 2170 MHz).

15


18-pole HTS Filter with Group Delay EqualisationIntroduction

• The selectivity can be significantly increased with the use of high-order filters, and there is a trend to develop high-order HTS filters to take advantages of miniature high Q HTS resonators .

• Unfortunately, higher order selective-only filters tend to result in a poorer phase performance even over the band center.

16


18-pole HTS Filter with Group Delay EqualisationIntroduction

Frequency (MHz)

1955 1960 1965 1970 1975 1980

Tran

smis

sion

(dB)

-140

-120

-100

-80

-60

-40

-20

030-pole Chebyshev18-pole quasi-elliptic 18-pole quasi-ellipticwith linear phase

Frequency (MHz)

1960 1962 1964 1966 1968 1970 1972 1974

Gro

up d

elay

(ns)

200

400

600

800

1000

1200

140030-pole Chebyshev18-pole quasi-elliptic 18-pole quasi-ellipticwith linear phase

All the three filters have a pass band of 15 MHz from 1960 MHz to 1975 MHz with the same ripple level, and are supposed to meet a selectivity of

70-dB rejection bandwidth of about 16 MHz

17


18-pole HTS Filter with Group Delay EqualisationDesign

1 2 65 9

3 74 8

1810 1413 17

11 1512 16

PORT 1

PORT 2

M25Qe1 Qe2M69 M10,13 M14,17

Coupling structure (cascaded quadrupletCoupling structure (cascaded quadruplet))

For our design, only one quadruple section, which consists of the resonators 10 to 13, will be used for the group delay equalization, while the

other three quadruplet sections are arranged for the high selectivity.

18


18-pole HTS Filter with Group Delay EqualisationDesign

Circuit modelling Circuit modelling

1955 1960 1965 1970 1975 1980Frequency (MHz)

Magnitude Response

-150

-100

-50

0

DB(|S[1,1]|)18_pole_15_MHz

DB(|S[2,1]|)18_pole_15_MHz

1960 1965 1970 1975Frequency (MHz)

Group Delay

-200

0

200

400

600

800

1000

1200

1400

GD[1,2] ~ (ns)18_pole_15_MHz

The 18-pole filter was designed to have a 15 MHz pass band at a canter frequency of 1967.5 MHz.

19


18-pole HTS Filter with Group Delay Equalisation

Implementation of Microstrip Quadruplet A Implementation of Microstrip Quadruplet A

(1)

03460.001822.03460.005706.0005706.004089.0

1822.004089.00

10

0000

0000

2

4525

4534

3423

2523

⎥⎥⎥⎥

⎦

⎤

⎢⎢⎢⎢

⎣

⎡

−−

⋅=

⎥⎥⎥⎥

⎦

⎤

⎢⎢⎢⎢

⎣

⎡

−

MMMM

MMMM

The desired coupling matrix for the first quadruplet, The desired coupling matrix for the first quadruplet, i.e. coupled resonators 2, 3, 4 and 5, is given byi.e. coupled resonators 2, 3, 4 and 5, is given by

Normalized frequency

0.990 0.995 1.000 1.005 1.010

S21

(dB

)

-100

-80

-60

-40

-20

0

Theory Simulation

20



Implementation of Microstrip Quadruplet B Implementation of Microstrip Quadruplet B

The desired coupling matrix for the first quadruplet, The desired coupling matrix for the first quadruplet, i.e. coupled resonators 10, 11, 12 and 13, is given byi.e. coupled resonators 10, 11, 12 and 13, is given by

(2)

03423.001785.03423.002047.0002047.003419.0

1785.003419.00

10

0000

0000

2

13,1213,10

13,1212,11

12,1111,10

13,1011,10

⎥⎥⎥⎥

⎦

⎤

⎢⎢⎢⎢

⎣

⎡

⋅=

⎥⎥⎥⎥⎥

⎦

⎤

⎢⎢⎢⎢⎢

⎣

⎡

−

MMMM

MMMM

Normalized frequency

0.990 0.995 1.000 1.005 1.010

S21

(dB

)

-100

-80

-60

-40

-20

0

Theory Simulation

21



Final layout of 18Final layout of 18--pole HTS microstrip filter pole HTS microstrip filter

The overall chip size is 74 mm x 17 mm on sapphire substrate

22



Fabricated 18Fabricated 18--pole HTS microstrip filter pole HTS microstrip filter

The filter was then fabricated on a 0.43mm-thick sapphire (Al2O3) wafer with double-sided YBCO films. The YBCO thin films have

a thickness of 300 nm and a characteristic temperature of 87K. Both sides of the wafer are gold-plated with 200 nm thick gold

(Au) for the RF contacts.

23



Measured responses Measured responses

dB 0

dB 0

-10 -5

-20 -10

-30 -15

-40 -20

-50 -25

-60 -30

-70 -35

-80 -40

-90 -45

-100 -50

S11 S21


ns1400

1200

1000

800

600

400

200

0

-200

-400

-600

Group Delay


The measured bandwidth is close to 15 MHz. The insertion loss of1.4 dB at the band center was measured, including the losses of the

contacts. The resonator Q is estimated to be larger than 50,000.

24


25


4-pole HTS Elliptic Filter2005

The filters were fabricated by using e-beam lithography and wet etching process. YBCO film is double side polished type. YBCO film thickness is 700 nm in both sides and one side isprotected with a gold layer. The substrate is LaAlO3 with the thickness of 0.5 mm.

26


Superconducting filters for radio astronomySuperconducting filters for radio astronomyBirmingham University, 2006

Measured at 22K

27


An Eight Pole Self-Equalised Quasi-EllipticSuperconductor Planar Filter For Satellite

Applications2005

28


An Eight Pole Self-Equalised Quasi-EllipticSuperconductor Planar Filter For Satellite

Applications2005

29


Qu ~ 4000 at 77K1.5 dB insertion loss at 77K

30


Tuning Fork Filter Design for Hand Scribe TuningGenichi Tsuzuki, Matthew P. Hernandez and Balam A. Willemsen

Superconductor Technologies, Santa Barbara, CAIEEE MTT-S 2005

Tuning HTS filters:

•Mechanical tuning (e.g. tuning screws)

•Laser trimming

•Thin dielectric layer deposition

•Hand scribe tuning ->

31


Tuning Fork Filter Design for Hand Scribe Tuning

Scribing here

So as not to damage HTS resonator

32


Tuning Fork Filter Design for Hand Scribe Tuning

33


Highly-Selective Electronically-Tunable Cryogenic Filters Using Monolithic, Discretely-Switchable MEMS Capacitor Arrays

The use of Micro Electromechanical Systems (MEMS) with High Temperature Superconductors (HTS) has enabled a new class of highly-selective tunable filters. HTS microstrip filters are generally planar, and are thus very well suited to subsequent monolithic processing such as MEMS technology.

34


Highly-Selective Electronically-Tunable Cryogenic Filters Using Monolithic, Discretely-Switchable MEMS Capacitor Arrays

A low loss electronically tunable filter was demonstrated using HTS/Au MEMS switched capacitor arrays. The two-pole filter was tuned by simultaneously varying the capacitance of each resonator by equal amounts. The total tuning range was about 25% with an average Q of 7,000 at 77 K.

MEMS switches

35


Improvement of Power Handling Capability

A research team at NTT (Nippon Telegraph and Telephone) Corporation has focussed on improving power handling of HTS filters and found that

• IP3 is enhanced by increasing HTS thin film thickness t. For YBCO filters, IP3 at 70 K increased from 53 to 65 dBm as t increased from 620 nm to 800 nm.

• Different materials and deposition methods can affect the powerhandling.

• A possible trade-off between the passband insertion loss, i.e.|S21|, and power handling capability in HTS bandpass filters.

36


2005

High impedance line would result in a smaller Qu, but can reduce maximum current density so as to increase the power handling.

37


Improvement of Power Handling CapabilityNTT, 2005

38


Improvement of Power Handling CapabilityNTT, 2005

Measured IP3Measured IP3

The IP3 of the 100-ohm CPW HTS filter is 62 dBm at 60K, while the IP3 of the 50-ohm CPW HTS filter is 54 dBm.

This means that the former can handle over 6 times as much power as that of the latter.

39


Summary

• Some recent developments of HTS filters have been reviewed, including miniature high performances HTS filters for wireless and satellite communications as well as radio astronomy applications.

• There is also a new trend to develop electronically tunable HTS filters using RF MEMS and ferroelectronic devices.

• Power handling capability can be improved through designs, fabrications processes and materials.

• Superconducting filter R&D will certainly continue at least for niche applications.

recent development in superconducting filtershome.eps.hw.ac.uk/~ceejh3/presentations/2006...

Documents