20130723 research accomplishment_ud

Research accomplishment (2003 ~ )

Semiconductor & Integrated Circuit Lab
Millimeter-wave INovation Technology research center

Taejong Baek
Department of Electronics and Electrical Engineering
Graduate School
Dongguk University


Millimeter-wave INnovation Technology research center

Dongguk University

Research field

1



Dongguk University

■ What is Millimeter-wave?
 Wide bandwidth: high data rate and high speed
wireless communication applications
 Short wavelength: small-sized and light-weighted circuit systems

Frequency (GHz)

30

2

10


3000
Submillimeterwave

Millimeter-wave

Micro-wave

Wave-length (mm)

300

1


0.1

Dongguk University

■ Advantages of Millimeter-wave

1. Large spectrum availability
⇒ Broadband system
⇒ Unused frequency bands

2. High reuse potential of frequency
⇒ Short range communications
from a few meters up to few kilometers

3. Small antenna and system size
⇒ Very short wavelength

3



Dongguk University

■

Examples of Millimeter-wave applications

ITS
Military

Medical

Millimeter-wave
Applications
Imaging

WLAN

system

Requirement of Millimeter-wave
Monolithic integrated Circuits
4



Dongguk University

 Thermal Evaporator / ULVAC EBV-10
 Rapid Thermal Process System (RTP) / KVR-020
 Plasma Enhanced Chemical Vapor Deposition
(PECVD) JCSS-41MR
 O2 Plasma Asher / Oxford plasma lab 80 plus
 Mask Aligner / Karl Suss MA6
 Inductively Coupled Plasma Reactive Ion Etching
(ICP-RIE) / KVICP-T4083
 E-Beam Evaporator System / KVE-T5560
 E-Beam Lithography System / Leica EBPG-4HR

Mask Aligner

ICP-Dry etcher

FC Bonder

Plasma Asher

 Au Plating System
 Vacuum Dry Oven / SB-CD520
 Lapping Machine / Allied MultiPrep TM System
 Furnace / Metritherm
 Surface Profiler / a-step 200
 Thin Film Analyzer / Tyger
 Flip Chip Bonder / Laurier M9
 Wedge bonder / Hybond 572-A
 Ball bonder / Hybond 626
 Spectrum & Vector Network Analyzer
 Semiconductor Characterization System / Keithley 4200-PCS
 Ansys HFSS & Agilent ADS Simulation Program
5


E-Beam Lithography


Furnace

Dongguk University

GaAs-based 70 nm MHEMTs

6



Dongguk University

■

Fabricated MHEMT

70 nm

<70 µm × 2 MHEMT>

7


<Resist profile of gate foot>


Dongguk University

Development of MMIC Libraries
■ 70 nm Gate Metamorphic HEMT
Gate length: 70 nm
Double exposure method
Tri-layer resist stack
▶ ZEP520 : DCB = 1.5 : 1
▶ PMGI
▶ PMMA950K : MCB = 1 : 1
Gate metal formation

SEM view of fabricated 70 nm gate

8


▶ Ti/Au = 500/4500 Å
Si3N4 passivation: 800 Å


Dongguk University

■

70 nm ×140 µm MHEMT (1)

DC performance
- Drain current density: 607 mA/mm
- Transconductance (gm): 1.015 S/mm

< I-V characteristics >
9


< Transconductance characteristics >

Dongguk University

■

70 nm ×140 µm MHEMT (2)

RF performance

- fT: 330 GHz
- fmax: 425 GHz

330 GHz
425 GHz

< RF characteristics >

10



Dongguk University

■ fT

comparison of HEMTs
[1] Y. Yamashita et al., IEEE Electron Device Letters,
vol. 23, no. 10, pp. 573-575, 2002.
[2] K. Shinohara et al., IEEE Electron Device Letters,
vol. 25, no. 5, pp. 241-243, 2004.
[3] T. Suemitsu et al., IEEE Trans. on Electron Devices,

[1]

vol. 49, no. 10, pp. 1694-1700, 2002.
[2]

[4] K. Shinohara et al., IEEE Electron Device Letters,
vol. 22, no. 11, pp. 507-509, 2001.

This
work

[4]

[5] K. Shinohara et al., IEEE MTT-S Digest,
vol. 3, pp. 2159-2162, 2001.
[6] S. Bollaert et al., IEE Electronics Letters,
vol. 38, no. 8, pp. 389-391, 2002.

[3]
[5]

[8]
[6]

[7] T. Parenty et al., Indium Phosphide and
[9]

[7]
[10]

Related Materials, pp. 626-629, 2001.
[8] A. Leuther et al., Indium Phosphide and
Related Materials, pp. 215-218, 2003.
[9] H. Wang et al., IEEE IEDM Digest,
pp. 239-242, 1993.
[10] Y. C. Lien et al., IEEE Electron Device Letters,
vol. 25, no. 6, pp. 348-350, 2004.
This work: Sung Chan Kim et al.,
IEEE Electron Device Letters,
vol. 27, no. 1, pp. 28-30, 2006.

11



Dongguk University

DAML
(Dielectric-supported Air-gapped Microstrip Line)

12



Dongguk University

Motivation of DAML
■ Motivation of DAML (1)
Conventional transmission lines

Microstrip line

CPW line

Substrate

Substrate

Substrate loss
Transmission line
 Basic elements
 Major cause of device loss

13


Demand of
MEMS technology


Dongguk University

Motivation of DAML
■ Motivation of DAML (2)
Shielded Membrane Microstrip
(1)

Substrate 1

(2)

Substrate 2

(3)

 Complex processes
Substrate
 Difficulty of integration with
MMIC/MIMIC

Shielded Membrane Microstrip
(1) Shield cover : 2 Masks
(2) Membrane plane : 3 Masks

DAML technology

(3) Ground plane : 1 Masks
Reference: S.V. Robertson et al., IEEE Trans. Microwave Theory and Tech.,
vol. 46, no. 11, 1998, pp. 1845-1849, 1998.
14



Dongguk University

DAML
■ DAML: Dielectric-supported Air-gapped Microstrip Line

 Surface micromachined transmission line
 Reduced substrate loss due to elevated signal line
 Simple process: Compatibility with standard MMIC/MIMIC fabrication
▶ Photo-lithography and low-temperature process
▶ Easily integrated with MMIC/MIMIC (3 additional masks required)
▶ Dielectric post used for mechanical stability (1 post/1 mm)

 Possibility of vertical integration (3-D integration)
Signal line
Dielectric post
Ground

S.I. GaAs substrate

15



Dongguk University

DAML
■ Formula for Effective Dielectric Constant in Partial Dielectric Layer

 h : Dielectric post height (µm)
 w : Signal line width (µm)
 g : Dielectric post gap (µm)
 d : Dielectric post size (µm)
 3hⅹ2 + w : Field area (by Ansoft HFSS)

g

d

d2
 r  1   polyimide 
g (3h  2  w)
Dielectric constant of DAML-Substrate is 1.108 by calculation.

w
h

 eff
3h ⅹ2 + w



d2

d2
 1   polyimide 
  1 1  


 1
polyimide



g (3h  2  w) 
g (3h  2  w) 
1





2
2
h

1 12

w












The effective dielectric constant εe ff is 1.086 by calculation. (Where, g = 500 µm, h = 10 µm, w = 44 µm, d = 40 µm)
16



Dongguk University

Process flow of the DAML
■ Process flow of the DAML


Ground metal (Ti/Au) and
dielectric post (polyimide)
formation



Sacrificial layer (AZ4903)
patterning



Seed metal (Ti/Au)
evaporation and
Electro-molding (AZ4903)
formation



Signal line (Au) formation
and sacrificial layer removal

Semi-insulating GaAs substrate




17



Dongguk University

Fabricated DAML
■ Dielectric Post

18



Dongguk University

Fabricated DAML
■ Sacrificial Layer

Reflow the photoresist for smooth metal overlay

19



Dongguk University

Fabricated DAML
■ Fabricated DAML

20



Dongguk University

DAML Characteristic
■ Comparison of transmission lines
[1] K. Nishikawa et al., IEEE MTT-S Digest, vol. 3,
2001, pp. 1881-1884.
[2] G.E. Ponchak et al., IEEE Trans. Components,
Packaging, and Manufacturing Technology-B,
vol. 21, no. 2, pp. 171-176, 1998.
[3] Suidong Yang et al., IEEE Trans. Microwave
Theory and Techniques,
vol. 46, no. 5, pp. 623-631, 1998.
[4] Y.C. Shih et al., Microwave Journal,
pp. 95-105, 1991.
[5] Youngwoo Kwon et al., IEEE Microwave
and Wireless Components Letters,
vol. 11, no. 2, pp. 59-61, 2001.
[6] S.V. Robertson et al., IEEE Trans. Microwave
Theory and Techniques,
vol. 46, no. 11, 1998, pp. 1845-1849, 1998.

This work: H. S. Lee et al.,
IEE Electronics Letters,
vol. 39, no. 25, pp. 1827-1828, 2003.
This work: Sung-Chan Kim et al., IEEE Microwave
and Wireless Components Letters,
vol. 15, no. 10, pp. 652-654, 2005.
21



Dongguk University

SDAML
■ Shielded DAML using Flip chip technique
 Ultra low loss: extended height (10 µm → 17 µm)
 Shielding effect
- Radiation, electromagnetic and environmental interference are avoided by enclosing
microstrip circuitry in a shielding cavity
 Simple process: not bulk micromachining (using flip-chip technique)

Connected Ground using Flip chip Stud

Upper Ground Plane

Polyimide Dielectric post

 h : Dielectric post height
 w : Signal line width
 g : Dielectric post gap

Air-bridged Signal line

 d : Dielectric post size

Lower Ground Plane

22



Dongguk University

Fabricated DAML
■ Fabricated DAML (height = 17 µm)

23



Dongguk University

DAML Characteristic (Measurement)
■ Insertion loss versus Signal line height
Signal line width: 44 µm, (dB/cm)

Simulation

80
(GHz)

1.85

1.89

1.53

110
(GHz)


1.63

94
(GHz)

24

Measurement

2.22

2.13


Dongguk University

SDAML Characteristic
■ Comparison of original DAML
4.0

DAML (h = 10 m)
DAML (h = 17 m )
SDAML (h = 17 m)

60
(GHz)

94
(GHz)

120
(GHz)

DAML
(10 µm)

1.87

2.56

3.1

DAML
(17 µm)

1.27

1.89

2.42

SDAML
(17 µm)

3.5

1.07

1.41

1.67

Insertion loss [dB/cm]

3.0
2.5
2.0
1.5
1.0
0.5
0.0
0

20

40

60

80

100

120

140

Frequency [GHz]

25



Dongguk University

Passive Device using DAML Technology
■ Comparison of electrical length
λg / 4 @ 94 GHz

Electrical length (λg / 4 @ 94 GHz )

CPW

Microstrip

DAML

Reduced Size DAML

26


304 µm

Microstrip

CPW

266 µm

DAML

792 µm

RS-DAML

478 µm


Dongguk University

■ W-band Reduced Size branch-line coupler

Total Size : 604 µm × 520 µm
27



Dongguk University

■ Measurement result of W-band Reduced branch-line coupler

Coupling loss: 3.61 dB
Transmission loss: 4.25 dB
Isolation: -35.5 dB
Return loss: -36.9 dB

28



Dongguk University

■

Comparison of W-band branch line coupler

Case

Coupling
loss (dB)

Return
loss (dB)

Chip size
(mm2)

Center
frequency
(GHz)

1
(CPW)

About -3.5

About -20

0.5 ⅹ0.5

90

RSC
DAML

-3.61

-36.9

0.6ⅹ0.52

94

Reference 1: M. Schlechtweg et al, GaAs IC Symposium, 1995. Technical Digest 1995,
17th Annual IEEE, 29 Oct.-1 Nov. 1995 Page(s):214 - 217

29



Dongguk University

W-band Hybrid Ring Coupler
■

Fabricated W-band hybrid ring coupler

10 µm

50 Ω
termination

 Coupler size:
1.46 mm (diameter)

30



Dongguk University

W-band Hybrid Ring Coupler
■

S-parameters of W-band hybrid ring coupler

 Transmission loss:
3.80 ± 0.08 dB
 Coupling loss:
3.57 ± 0.22 dB
(@ 85-105 GHz)

31



Dongguk University

Hybrid Ring Coupler
■

Comparison of W-band hybrid ring coupler

Case

Transmission Coupling loss
loss (dB)
(dB)

Isolation
(dB)

Center
frequency
(GHz)

1
(CPW)

About -5.5

About -4.7

About -30

94

This
work

-3.72

-3.35

-34

94

Reference 1: Hiroyuki Matsuura et al, IEEE MTT-S Digest, 1996, pp. 389-392
This work: Sung-Chan Kim et al, IEEE MWCL, vol. 15, no. 10, pp. 652-654, 2005.

32



Dongguk University

■ W-band reduced ring hybrid coupler

Diameter : 0.888 mm

33



Dongguk University

■ Comparison of coupler sizes
Reduced to 63 % in area

Conventional Coupler
Diameter : 1.460 mm

34

Reduced Coupler
Diameter : 0.888 mm



Dongguk University

■ Measurement result of W-band reduced ring hybrid coupler
0

0
-10

S-parameter [dB]

S-parameter [dB]

-20

-30

-40

-50

S21Thru
S31coupling
S23Isolation

-60
75

80

85

-10

-20

-30

S11
S22
S33

-40

90

95

100

105

Frequency [GHz]

Insertion loss

110

70

75

80

85

90

95

100

105

115

Frequency [GHz]

Return loss

Coupling loss: 4.35 dB

Isolation: -48.23 dB

Transmission loss: 4.44 dB
35

110

Return loss: below -25 dB (all port)



Dongguk University

■

Comparison of W-band hybrid ring coupler

Case

Transmission
loss (dB)

Coupling loss
(dB)

Isolation
(dB)

Diameter
(mm)

Center
frequency
(GHz)

1
(CPW)

About -5.5

About -4.7

About -30

About 0.7

94

DAML

-3.72

-3.35

-34

1.46

94

RSC
DAML

-4.44

-4.35

-48.23

0.88

94

Reference 1: Hiroyuki Matsuura et al, IEEE MTT-S Digest, 1996, pp. 389-392

36



Dongguk University

■ Novel W-Band Dual Mode Stepped Impedance Resonator

BPF Using DAML Technology

(b)

(a)

(a)

Fabricated BPF

(b)

(a) MIM coupling capacitor
(b) Stepped Impedance Perturbation

**Journal of the Korean Physical Society., vol. 51, no. 10, pp. S280-S283, December, 2007

37



Dongguk University

■ Measured Result of W-band BPF
5
0

Insertion Loss (dB)

-5
-10
-15
-20
S11

-25

S22

-30
-35

▶ Step Impedance Ratio: 0.5

S21
S12

-40
60

▶ Perturbation Length: 275 µm

Simulation
65

70

75

80

85

90

95

▶ MIM Capacitor Size: 75 µm2

100 105 110 115 120

Frequency (GHz)

- Insertion Loss: 2.65 dB @ 97 GHz

- Relative Bandwidth: 12 %
38



38
Dongguk University

■ 60-GHz CPW-fed Dielectric-Resonator-Above-Patch

Antenna for Broadband WLAN Applications Using DAML Technology

**Microwave and Optical Technology Letters., vol. 49, Issue. 8, pp. 1859-1861, 2005
39



Dongguk University

■ Fabricated Antenna

(a) Fabricated patch using DAML
(b) 60 GHz RDRA
(c) Proposed antenna
(d) Antenna integrated by 60 GHz VCO

40



Dongguk University

■ Measured Results

41



Dongguk University

3-D W-band Single Balanced
Active Mixer

42



Dongguk University

Mixer with DAML coupler

Design strategy



MEMS coupler

► MEMS library


Diode & CPW lines
► MMIC library

Schematic

43



Dongguk University

Single Balanced Active Mixer
■

Layout
RF
70 nm gate
MHEMT

Dielectric post
IF1

LO

IF2

Ring coupler
based on DAML

44



Dongguk University

■

Interference of DAML and CPW lines

DAML

 For the lowest reflection of DAML
► Distance of Airbridge to DAML : 90 ~ 150 µm

45



Dongguk University

■

Process flow of the single balanced mixer
GaAs epi-wafer


46



Dongguk University


Mesa etching

MHEMT


47



Dongguk University


Ohmic contact formation

MHEMT


48



Dongguk University


Resistor formation

MHEMT

Resistor


49



Dongguk University


70 nm gate patterning, narrow recess, and gate metalization

MHEMT

Resistor


50



Dongguk University


First metal formation

Ground

MHEMT

Resistor

Capacitor

CPW

Ground


51



Dongguk University


Dielectric (Si3N4) deposition

Ground

MHEMT

Resistor

Capacitor

CPW

Ground


52



Dongguk University


Dielectric (Si3N4) RIE

Ground

MHEMT

Resistor

Capacitor

CPW

Ground


53



Dongguk University


Second metal (air-bridge) formation

Ground

MHEMT

Resistor

Capacitor

CPW

Ground


54



Dongguk University


Dielectric (polyimide) post formation

Ground

MHEMT

Resistor

Capacitor

CPW

Ground


55



Dongguk University


DAML formation

Hybrid ring coupler based on DAML

Ground

MHEMT

Resistor

Capacitor

CPW

Ground


56



Dongguk University

■

Fabricated single balanced mixer

IF1

IF2

 External balun for IF’s

70 nm
MHEMT
RF

 W-band coupler size :
1.46 mm (diameter)

 Chip size :
Hybrid ring coupler

1.8 mm × 2.1 mm

LO

57



Dongguk University

■

Conversion loss vs. LO input power

 Conversion loss:
2.5 dB

- RF frequency: 94 GHz
- RF power: -10 dBm
- LO frequency: 94.2 GHz
- LO power: 6 dBm

58



Dongguk University

■

LO-to-RF isolation

 LO-to-RF isolation:
< -30 dB

- LO freq.: 93.65-94.25 GHz
- LO power: 0 dBm

59



Dongguk University

■

Comparison of W-band mixers (1)
LO
RF
RF-LO
Frequency Frequency Isolation
(GHz)
(GHz)
(dB)

Case

Mixer Design
Features

Conversion
Gain (dB)

Device
Technology

1

S.E. active mixer

0.8

0.1 µm InP HEMT

94

94.5

-

2

S.B. resistive mixer

-8

0.1 µm InP HEMT

83

94

-27

3

S.B. resistive mixer

-12.8

0.1 µm GaAs PHEMT

93

93.2

-

4

S.B. diode mixer

-7.5

0.1 µm GaAs PHEMT

93

94

-18

5

S.B. diode mixer

-9

0.1 µm GaAs PHEMT

94

95

-

6

S.B. diode mixer

-10

0.1 µm InP HEMT

94

94.5

-

This
work

S.B. active mixer

-2.5

70 nm GaAs MHEMT

94.2

94

-33

( S.E. : Single Ended, S.B. : Single Balanced )
60



Dongguk University

■

Comparison of W-band mixers (2)
Single balanced active mixer:

Low conversion loss: high-performance 70 nm MHEMTs
High isolation: hybrid ring coupler based on DAML
- References
[1] Robinder S. Virk et al., IEEE MTT-S Digest, 1997, pp. 435-438.
[2] A. R. Barnes et al., IEEE MTT-S Digest, 2002, pp. 1867-1870.
[3] K. W. Chang et al., IEEE Microwave and Guided Wave Letters, vol. 4, no. 9, pp. 301-302, 1994.
[4] K. W. Chang et al., IEEE Transactions on Microwave Theory and Techniques, vol. 39, no. 12, pp. 1972-1979, 1991.
[5] K. W. Chang et al., Proc. IEEE Microwave and Millimeter-wave Monolithic Circuits Symposium, 1993, pp. 41-44.
[6] Robinder S. Virk et al., IEEE MTT-S Digest, 1997, pp. 435-438.
This work: Sung Chan Kim et al., IEEE Electron Device Letters, vol. 27, no. 1, pp. 28-30, 2006.

61



Dongguk University

A transceiver module for FM-CW radar sensors
using 94 GHz dot-type Schottky diode mixer

Taejong Baek
Graduate School
Dongguk University



Dongguk University

Introduction

63



Dongguk University

Introduction

64


Motivation


Dongguk University

Introduction

Passive & Active

Objects also reflect the radiation emanating from the environment to a degree of reflectivity which is the complement
of their emissivity; the sum of the emissivity and the reflectivity is 1.

Passive system concept
High Sensitivity receivers are required
Thermal noise

Antenna aperture affects resolution and SNR

Object

Direct measure of temperature (sub K accuracy)
Can detect objects through differences in emissivity

T

Emissivity =

radiation + reflectivity (from the natural background radiation)
Active system concept
Also known as a radar (using oscillator)

Received

Transmit a signal and receive scattered waveform

Object

Detected unwanted objects
Transmitted

T

Need to large computational resources

Emissivity = radiation + reflectivity (from the signal source)

65



Dongguk University

InP Gunn Diode

66



Dongguk University

InP Gunn diode

Epi structure

Epi structure of InP Gunn diode

67



Dongguk University

InP Gunn diode
1. Wafer Cleaning

Process flow 1~2

1) Initial cleaning
TCE
Acetone
IPA
D.I. water rinse

1)Photo resist (PR) coating

2. Formation of top side trench

2)Soft baking
3)Alignment & Exposure
4)Development
5)Post baking
6)Wet etching
7)PR strip

68



Dongguk University

InP Gunn diode
3. Cathode ohmic metalization

Process flow 3~4

1)Cleaning
2)Oxide etching
3)Metal evaporation
4)Protection layer

4. Integral heat sink (IHS)
patterning lithography
1) Cleaning
2) Photo resist (PR) coating
3) Soft baking
4) Alignment & Exposure
5) Post Expose Baking
6) Development

69



Dongguk University

InP Gunn diode

Process flow 5~6

5. 2nd seed evaporation
1)Cleaning
2)2nd seed evaporation

6. 2nd plating (formation of support layer)
1) Au plating

70



Dongguk University

InP Gunn diode

Process flow 7~8

7. Wafer thinning (lapping & polishing)

1) Wafer mount
2) Lapping 640 um lapping
3) Wafer de-mount
4) Cleaning
1)Cleaning

8. Anode ohmic metalization

3)Soft baking
5)Reverse baking
6)Flood exposure
7)Development
8)Oxide etching
9)Metal evaporation
10)Lift-off

71



Dongguk University

InP Gunn diode
9. Overlay metallization

Process flow 9~10
1)Seed evaporation
3) Soft baking
4) Alignment & Pre-exposure
5) Development
6) Oxide etching
7) Au plating
8) PR strip
9) Seed etching
1)Cleaning

10. MESA etching

3)Soft baking
5)PEB (post exposure bake)
6)Development
7)Hard baking
8)Dry etching
9)PR strip

72



Dongguk University

InP Gunn diode

Process flow 11

11. Gold & 2nd seed etching
1)
2)

Cleaning
Oxide etching

3) Au etching

(Cathode)

anode
InP

Fabricated InP Gunn diode

73



Dongguk University

Packaged Diode

74



Dongguk University

InP Gunn diode

Packaging

Package element
Lid
AgSn solder
Au wire
Gunn diode chip
Ceramic ring
AuSn solder
Stud

3-48 UNC-2A THREAD

75



Dongguk University

InP Gunn diode

Package process 1~2

1. Ceramic ring junction

Ceramic ring

Stud
(3-48 UNC-2A THREAD)

2. Die attach
Chip

76



Dongguk University

InP Gunn diode

Package process 3~4

3. Maltese Cross Bonding
Maltese Cross

4. Lid junction
Lid

77



Dongguk University

InP Gunn diode

X-ray image of InP Gunn diode

78


Packaged Diode

Packaged InP Gunn diode


Dongguk University

InP Gunn diode

DC characteristic

DC I-V measurement result

InP Gunn diode chip

79


Packaged InP Gunn diode


Dongguk University

InP Gunn diode

RF characteristic

Measurement results of packaged InP Gunn diode

Chip number

Voltage [V]

Current [mA]

Oscillation frequency [GHz]

Output Power [dBm]

1

12.4

299

94

17.8

2

11.7

260

93.98

16

3

9.7

299

94.25

15.6

4

10.9

349

93.9

16.6

5

9.3

349

93.8

16.4

Oscillation characteristics of fabricated InP Gunn diode

80



Dongguk University

Transceiver

81



Dongguk University

82



Dongguk University

83



Dongguk University

84



Dongguk University

85



Dongguk University

86



Dongguk University

87



Dongguk University

Active Radar Sensor

Cross section

Flip-chip

Top view

Flip chip packaging configuration

88



Dongguk University

Active Radar Sensor
(a)

(b)

Flip-chip
(a) Gold bumps were then flattened
using a flip-chip bonder of model M9
from LaurierTM at a press force of
100 g/bump
(b) epoxy can spread out evenly on
them. Flattened bump had a typical
diameter of 100 μm and a height of
45 μm
(c) Silver epoxy was then applied onto
the flattened gold bumps using a
capillary tool with a 3-mil Au ribbon
wire and a manual wire bonder of
model 572A-40 from HybondTM . The
resulting bump had 23 μm of silver
epoxy on top 45 μm of gold.

(c)

89


(d)

(d) MMIC chip and the sapphire
substrate were flip-chip bonded with
the epoxy in between. The M9 bonder
was used with a bonding force of 30
g/bump and a bonding time of 90
second at 110 °C. Silver epoxy was
compressed down to 5 μm.


Dongguk University

Active Radar Sensor

RF Characteristic
0

S-parameter [dB]

-5
-10
-15
-20
-25
-30

Insertion loss
Return loss

-35
75

80

85

90

95

100

105

110

115

Frequency [dB]
Reference

Bump material

Bonding condition

Loss/frequency

[1]

Au

350℃, 20 g/pillar

0.2 dB/77 GHz

[2]

Au

275℃, 230 N/mm2

0.2 dB/NA

This work

Au / Ag epoxy

110℃, 30g/bump

0.205 dB/94 GHz

[1] Aoki, S.; Someta, H.; Yokokawa, S.; Ono, K.; Hirose, T.; Ohashi, Y.;, “A flip chip bonding technology using gold pillars for
millimeter-wave applications,” in Proc. IEEE MTT-S Int. Microw. Symp. Dig. 1997, vol. 2, pp. 731-734, 1997.
[2] Heinrich, W.; Jentzsch, A.; Richter, H.;, “Flip-chip interconnects for frequencies up to W band,” Electron. Lett., vol. 37, issue 3, pp.
180-181, 2001.
90



Dongguk University

Active Radar Sensor

91



Test image

Dongguk University

Active Radar Sensor

Shear test

The shear tests were performed using a model 4000 series shear test machine from DageTM , widely used
to measure the interconnection strength between the MMIC chip and the sapphire substrate. The speed of
the shear blade was 300 μm/s, with the tip located at 40 μm above the surface of the sapphire substrate.
The flip-chip bonded die, which used proposed low-temperature flip-chip bonding method and 20 bumps
of 100 μm diameter, was separated at a force of 900 g.
Bonding temperature

Die shear strength [mg/ ㎛2]

100℃

1.55

150℃

2.19

200℃

4.38

ACP

220℃

1.05

ACF

220℃

1.07

[3]

CuSn

260℃

2.17

This work

Au/Ag epoxy

110℃

5.73

Reference

[1]

Bump material

Indium

[2]

[1] Kun-Mo Chu, Jung-Sub Lee, Han Seo Cho, Hyo-Hoon Park, Duk Young Jeon, “A fluxless flip-chip bonding for VCSEL arrays using
silver-coated indium solder bumps,” IEEE Trans. Electronics Packag. Manuf., vol. 27, no. 4, pp. 246-253, 2004.
[2] Tan Ai Min, Sharon Pei-Siang Lim and Charles Lee, “Development of solder replacement flip chip using anisotropic conductive
adhesives,” in Proc. 5 th Electron. Packag. Tech. Conf. 2003, pp. 390-396, 2003.
[3] Katsuyuki Sakuma, Jun Mizuno, Noriyasu Nagai, Naoko Unami, and Shuichi Shoji, “Effects of Vacuum Ultraviolet Surface
Treatment on the Bonding Interconnections for Flip Chip and 3-D Integration.” IEEE Trans. Electronics Packag. Manuf., vol. 33, no. 3,
pp. 212-220, 2010.

92



Dongguk University

93



Dongguk University

94



Dongguk University

Studies of the Millimeter-Wave Radiometric
Sensor and Fabricated Passive Imaging System

Taejong Baek
Advisor : Jin-Koo Rhee
Graduate School
Dongguk University



Dongguk University

Introduction

96



Dongguk University

Introduction

Motivation

The increased threats of criminal or terrorist action in recent years have led to the development of many techniques for
the detection of concealed weapons, contraband, explosives or other threats.

Traditional method
Metal detectors
X-ray imaging systems

Insufficient for modern and health threats!
Plastic and liquid explosive
Plastic or ceramic guns and knives
Ionizing radiation

Advanced method
Millimeter-wave/terahertz security systems

97



Dongguk University

Introduction

98


Private issue


Dongguk University

Background and Theory

Radiation law

Every object generates electromagnetic emissions at all wavelengths with intensity proportional to the product of its
physical temperature and its emissivity in accordance with Planck's radiation law.

Object radiation
Object emissivity + reflectivity (reflect the radiation form the environment) = 1
Radiation = Object reflectivity + Object emissivity

Object

Emissivity (%)

Human skin

65 ~ 95

Plastics

30 ~ 70, depending on type

Paper

30 ~ 70, depending on moisture content

Ceramics

30 ~ 70

Water

50

Metal

~0

Both the amplitude and the wavelength of the radiation peak are dependent on the temperature of the object.
99



Dongguk University

System Arrangement

Target Specification

 Real–time (≥ 1 Hz) imaging (82 GHz to 102 GHz )
 Spatial resolution (≤ 5 cm2)
 1°C temperature resolution at (≥ 1 Hz)
 Full–body scanning (3m stand-off )

100



Dongguk University

System Arrangement

NETD

Noise equivalent temperature difference (∆ )
The minimum detectable change in signal at the input is equal to the noise power at the output times the reciprocal of the squared
response of the system evaluated at Tsys. Sometimes radiometric resolution is referred to as the noise equivalent temperature difference,
i.e. “NETD”, or sensitivity.

∆ =

∆

Whole imaging measurement time (t), the number of detector (n), and total number of picture point (m):

=
number of samplings (sn ), reflector scanning cycle time (rt ):

=

101


×


Dongguk University

System Arrangement

Integration Time

Total number of picture point (m):

=

×

=

whole imaging measurement time (t):

=

×

=

=

/

×

in this case, integration time ( ) is

=
102


=

= .

/


Dongguk University

System Arrangement

Noise Temperature

Radiometer input signal (thermal noise) power:
=

(

× 1000) + 10

(∆ )

where Δf is the bandwidth in hertz (set 20 GHz)

=−

+

≈ −

Lens concentrate thermal noise ratio (dB)

×

% = 10 dB

Hence, a gain of 70 dB at least is required to provide at the output a detectable signal (≥0 dBm). The total
input thermal noise is through the lens is –70 dBm + 10 dB = –60 dBm. Therefore, we need an amplifier of
least 60 dB or more gain.

103



Dongguk University

System Requirement

Requirements

The system noise temperature at the receiver input is Tsys= TA+ Trec

∆ =

∆

where Trec is the noise temperature of the detector, TA is the effective temperature of the antenna, Δf is the RF bandwidth and τ is the
post-detection integration time constant.

System elements to be considered for high performance:
1.

Antenna return loss

2.

LNA return loss / noise figure

3.

Frequency bandwidth of each element

4.

Transition return loss / insertion loss

5.

Diode noise temperature

Basic radiometer model

104



Dongguk University

System Arrangement
Radiometer Type


System

Characteristics
superior low noise temperature
complicated structure

Dicke
radiometer

Super heterodyne receiver

need local oscillator
high cost

Full power
radiometer

low noise temperature
Direct– detection receiver

simple structure
low power consumption

Component

Parameter


NETD (ΔT)
Resolution

≤ 15 dB
≤ 10 dB

Gain

≥ 60 dB
≤ – 15 dB

Gain

≥ 15 dBi

Return loss

≦ – 25 dB

VSWR

105

20 GHz

Return loss

Detector

1 scene/sec

Noise figure

Antenna

Frame Rate

Noise figure
LNA

≤ 5 cm

Bandwidth (Δf)

System

≤1K

≦ 1.2

Output voltage range

100 mV ~ 1000 mV

Sensitivity

> 500 mV/mW (0 dBm)



Dongguk University

Development of
Radiometer Receiver

106



Dongguk University

Antenna

Gain

An antenna with a large aperture has more gain than a smaller on; just as it captures more energy from a passing radio wave, it also
radiates more energy in that direction. Gain may be calculated as
=
with reference to an isotropic radiator; ƞ is the efficiency of the antenna and A is the aperture area.

Antenna is designed to have the peak gain of 17.5 dBi at the center frequency of 94 GHz, and
the return loss of less than -25 dB in W-band, and the small aperture size of 6 mm × 9 mm for
antenna configuration with high resolution.

107



Dongguk University

Antenna

Efficiency

Return loss is a measure of the reflected power and forward power ratio.

=−

−
+

Specification
Frequency range (GHz)
Waveguide type

75 ~ 110
WR-10

VSWR (max)

1.1

Mid-band Gain (dB Typ)

17.5

Total Length (L)
Aperture size (W × H), mm2

108



32
9×6

Dongguk University

Antenna

Antenna – array for multi-channel

Multi-channel antenna array
To obtain high accuracy and resolution, various methods are
proposed. Conventional beamforming method is a straight forward
method, but its angle resolution is limited by aperture of the antenna
array, which implies that the number of antennas should be increased
to satisfy resolution requirement. 8 × 2 horn arrays antenna
developed for available real-time passive imaging system.

109



Dongguk University

Lens

Lens - specification
Specifications
89 GHz ~ 99 GHz
Frequency
(center frequency 94 GHz)
Center wavelength

3.191 mm(c=υλ)

Diameter

≤ 200 mm

Material

Teflon

Viewing angle

±11.3°(target distance 3m)

Optical path and spot-patterns for different incident angles
are calculated and compared without or with an extended
hemispherical lens by using ray-tracing method.
Teflon was the material of the lens, the lens is reflected
from the surface of the lens is placed in the hole. In
addition, depth of non-reflective layer is 0.66 mm, pitch
0.7 mm, and groove length 0.4 mm.

110



Dongguk University

System Specification

111


LNA – Oscillation


Dongguk University

LNA

LNA module – 4-stage
80
60

S11

S-Parameter [dB]

40

S21
S12

20

S22

0

-20
-40
-60
-80
80

85

90

95

Frequency [GHz]

100

105

110

4-stage LNA module measured characteristics
Average linear gain: 65.8 dB @ 81 ~ 102 GHz
68.2 dB @ 94 GHz

112



Dongguk University


113


Detector – Transition


Dongguk University


114


Detector – Output


Dongguk University


115


Size – Array System


Dongguk University

Radiometer Receiver

Radiometer

radiometer receiver

16 receivers array multi-channel radiometer

116



Dongguk University

Development of
Security Screening System

117



Dongguk University


118


System block diagram


Dongguk University

15V
+V -V FG

12V, 5V

24V

LNG Com V2 Com V1

L N

+V-V FG ACAC

3.3V

Circuit map

3.3V

+ - G AC

+ - G AC

Power2

Power2

Power2

DirectLine

DirectLine

(Floating)

(Floating)

(Floating)

(Floating)

(Floating)

G

AC

Power part

VGA

IR Signal

NTSC Signal

(with Ground) (with Ground)
DC 12V
DC 12V
FG
NTSC
CAM

(with Ground)

DC 12V
DC

FG

CAM

WiFi

Ke yboard

ADC

Cont.
IR

CAM1

USB To PC

MMW Sensor

DC 12V

1~16 Ch.
Drain

AC G

Mouse

USB

To S ensor Part

Gate

(with Ground)

FAN
Shield box

CAM2

To S ensor Part
(with Ground)

Monitor

DC 24V
G

DC 15V
DC 5V

G

G
Embedded
S ystem

Sensor part

DC 15V

Control signal

DC 5V

Step
motor
Driver

Ste p

PC part

Motor

Serial to USB

RS232

Encoder

USB To PC
(with Ground)



Dongguk University


Ch-1

Ch-6

Ch-7

Ch-8

Ch-9

Ch-10

Ch-11

Ch-12

Ch-13

Ch-14

Ch-15

Ch-16

IR

Ch-4

Ch-5

CCD

Ch-2

Ch-3

Measurement S/W

0.6 m (16 pixel)

1.6 m
(variable
pixel)

120



Dongguk University

Comparison with
Commercial MMW Imaging

121



Dongguk University

Name

L3
safeview
provision
100

Agilent

Brijot
BIS-WDS

ThruVision
T4000

This Work

Application

Portal

Portal

Portal

Stand-off

Stand-off
3-10m

Stand-off
3-10m

Stand-off
3m

Active/
Passive

Active

Active

Passive

Passive

Passive

Passive

Passive

Frequency
(Bandwidth)

24-30GHz

24GHz

94GHz
(> 10GHz)

76-94GHz

76-94GHz

90GHz
(20 GHz)

250GHz

94GHz
(10 GHz)

Imaging
System

Source &
Receiver
array
rotates
around
subject

Active
antenna
array:
programm
-able
fresnel
zone-plate

Folded
Schmidt
camera:
conical
scan, offaxis
rotating
mirror

Mechanical :
Tilted
rotating
mirror

Frequency
scanned
antenna
and
reflector

Phased array
of freq
scanned
antennas

64

24

1

232

Receiver
technology

InP
MMIC

InP Direct
detection

InP
HEMT
MMIC

System
NETD

5K

1K

1-3K

6K

0.3degree

10mm

6mrad

0.5Hz

Receivers

Qinetiq

Smiths
Tadar

Sago Trex
ST150

Real Time
Imager

Stand-off
8 – 30m

Portal

Stand-off
5m

Passive

Passive

Passive/
Active

35GHz

94GHz

base

1

64

Spatial
Resolution

0.5cm

0.5cm

Refresh rate

2Hz

15Hz

15Hz

10HZ

90cm

80cm

60cm

Aperture
Dimensions
L× W × H
122

0.75cm
2cm

SPO 20

150 × 150
90 × 10
× 270 Semiconductor & Integrated Circuit Lab
× 90

Receiver
array of
multichannel
scanned
antennas
and reflector
16

16
GaAs
Schottky
mixer

GaAs Direct
detection (z-b
Schottky
diode)

1K

1-1.5K

≤ 2K

6mrad
128×192
pixel

5cm

3cm

>4.5 cm
16×128 pixel
(variable)

30Hz

4-10Hz

1-3Hz

1Hz

18cm

12cm

20cm

250 × 160
71 × 33
× 220
× 48

50 × 50 ×
110
Dongguk University

Discussion

System Noise Temperature

Specification

Brijot (indoor)

This work (indoor)

Center Frequency

90

94

Bandwidth (Δf)

20

10

No. of Receiver

16

16

System NETD (ΔT)

1K

≤2K

Spatial Resolution

5 cm

5 cm

Image Quality

clearly

noisily

Reflesh Rate

4 ~ 10 Hz

1 Hz

Brijot

∆ =

∙

× . ∙

∙

× . ∙

,

=

×

=

,

=

×

=

Our system

∆ =

123

=

×


=

Dongguk University

Video Demo

124



Dongguk University

Video Demo

125


2011. 01. 31.


Dongguk University

Conclusion

126



Dongguk University

Conclusion

Summary

Type : 82~102 GHz Passive imaging (indoor)
Bandwidth : 20 GHz
Dimension (cm): 50 × 50 × 110
IR and CCD image fusion
Spatial resolution : 4.5 cm (16 × 128 pixel)
Temperature sensitivity : 2℃
Antenna

127

System

Mid-band Gain

Return loss

Size

WR-10

1.1

17.5 dBi

< - 25 dB

9 × 6 × 32 mm

Frequency

Gain (1st)

Returen Loss
(1st)

Gain (4st)

Returen Loss
(4st)

Noise Figure
(Chip)

19.6 dB

-11 dB

65.8 dB

-5.7 dB

4.1 dB

Frequency

Operation
range

Output voltage

Minimum
detectable
power

Sensitivity
(input 0 dBm)

-10 ~ 15 dBm

100 ~ 1500 mV

-20 dBm

350~400 mV/mW

NETD

Spatial
resolution

Refresh rate

Reflector
Scan angle

MMW lens
diameter

2K

Security
screening

VSWR (max)

75 ~ 110 GHz

Detector
module

Waveguide type

77 ~ 110 GHz

LNA module

Frequency

82 ~ 102 GHz

Passive
Imaging
sensor

4cm

1Hz

± 20 °

20 cm



Dongguk University

20130723 research accomplishment_ud

Recommended

Recommended

More Related Content

What's hot

What's hot (19)

Viewers also liked

Viewers also liked (20)

Similar to 20130723 research accomplishment_ud

Similar to 20130723 research accomplishment_ud (20)

Recently uploaded

Recently uploaded (20)

20130723 research accomplishment_ud