DSRC provides high speed radio link between Road Side Equipment and On-Board Equipment within the narrow communication area.In this paper,a 5.8 GHz down-conversion mixer for DSRC communication system is designed and fabricated using 0.8 Pm SiGe HBT process technology and RF/LO matching circuits,RF/LO input balun circuits and IF output balun circuit are all integrated on chip.The measured performance is 7.5 dB conversion gain,-2.5 dBm input IP3,46 dB LO to RF isolation,56 dB LO to IF isolation,current consumption of 21 mA for 3.0 V supply voltage and the chip size of fabricated mixer is 1.9 mm X 1.3 mm

Bae, Hyun-Chul

Cho, Kyoung Ik

Kang, Jin-Yeong

Kim, Sang Hoon

Lee, Ja-Yol

Lee, Sang-Heung

Lee, Seung-Yun

Park, Chan Woo

English

AMS Acta

A 5.8 GHz Mixer using SiGe HBT Process 
Sang-Heung Lee, Ja-Yol Lee, Seung-Yun Lee, Chan Woo Park, Sang Hoon Kim, Hyun-Chul Bae,           
Jin-Yeong Kang, and Kyoung-Ik Cho 
SiGe Devices Team, Electronics and Telecommunications Research Institute, Republic of Korea 
 
Abstract  — DSRC provides high speed radio link 
between Road Side Equipment and On-Board Equipment 
within the narrow communication area. In this paper, a 5.8 
GHz down-conversion mixer for DSRC communication 
system is designed and fabricated using 0.8 m SiGe HBT 
process technology and  RF/LO matching circuits, RF/LO 
input balun circuits and IF output balun circuit are all 
integrated on chip. The measured performance is 7.5 dB 
conversion gain, -2.5 dBm input IP3, 46 dB LO to RF 
isolation, 56 dB LO to IF isolation, current consumption of 
21 mA for 3.0 V supply voltage and the chip size of 
fabricated mixer is 1.9 mm X 1.3 mm. 
I. INTRODUCTION 
ITS (Intelligent Transportation Systems) technology 
has been developed to solve the traffic problem such as 
traffic congestion and accidents and reduce the overall 
congestion cost. The final goal of ITS will be to improve 
the traffic efficiency and mobile safety without new road 
construction. DSRC (Dedicated Short Range 
Communication) provides high speed radio link between 
Road Side Equipment (RSE) and On-Board Equipment 
(OBE) within the narrow communication area. DSRC 
communication system has been developed worldwide 
and recently applied for Electronic Toll Collection (ETC), 
but most of all ITS services will be provided by DSRC 
communication [1]. 
The SiGe hetero-junction bipolar transistor (HBT) has 
been considered to be more suitable for RF integrated 
circuits than the Si bipolar junction transistor (BJT) 
because its electrical properties, such as current gain, 
power consumption, small-signal unity-gain frequency, 
and maximum oscillation frequency are superior to those 
of the Si BJT [2]. Because of having many advantages 
for those RF applications, SiGe HBT device has been 
adopted as a good candidate for manufacturing RF 
components such as LNAs, Mixers, VCOs, PLLs, RF 
transceivers. 
Down-conversion mixers, which convert radio 
frequency (RF) signal to intermediate frequency (IF) 
signal, are very important building blocks within a radio 
system. Their performance affects the performance 
requirements of the entire system and the performance 
requirements of other building blocks. 
In this paper, a 5.8 GHz down-conversion mixer 
including RF/LO matching circuits, RF/LO input balun 
circuits and IF output balun circuit for DSRC receiver is 
designed and fabricated on chip, using SiGe HBT 
process technology of Electronics and 
Telecommunications Research Institute (ETRI). The 
measured performance was 7.5 dB conversion power 
gain, -2.5 dBm input IP3, 46 dB LO to RF isolation, 56 
dB LO to IF isolation, current consumption of 21 mA for 
3.0 V supply voltage. 
II. SIGE HBT DC AND AC CHARACTERISTICS 
Electrical performance parameters of SiGe HBT such 
as cut-off frequency (fT), maximum oscillation frequency 
(fmax), minimum noise figure (NFmin) are critically 
dependent on not only the base thickness, but also the 
fabrication process. We used RPCVD system to grow 
base epitaxial layer, and adopted LOCOS isolation to 
separate device and device terminals. The maximum 
values of fT/fmax were 41 GHz/42 GHz at VCE = 2V, IC = 
1.83mA as shown in Fig. 1. In Table 1, the main DC and 
AC parameters of HBT with emitter area of 0.5  6.0 
m2 are summarized. Passive elements used in this paper 
were MIM capacitor, parallel-branch spiral inductor, and 
resistors composed of metal, emitter poly-silicon, and 
base poly-silicon. 
 
 
0.5 1.0 1.5 2.0 2.5 3.0 3.5
15
20
25
30
35
40
45
f T
 [
G
H
z
]
IC [mA]
 VCE=1
 VCE=2
 VCE=1
 VCE=2
15
20
25
30
35
40
45
 f
m
a
x
 [
G
H
z
]
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Fig. 1. AC characteristics of SiGe HBT 
III. SIGE HBT MIXER DESIGN 
The architectures of DSRC RF front-end receiver and 
down-conversion mixer in this receiver are shown in Fig. 
2. The LNA output and LO output signals go RF single 
input port and LO single input port of mixer, respectively, 
and single output signal of mixer goes IF input port. The 
5.81 GHz single-ended RF input and the 5.495 single-
ended LO input are converted to be differential to feed in 
the double balanced mixer by use of on-chip active balun. 
11th GAAS Symposium - Munich 2003 509
Fig. 3 shows the single-input, balanced-output 
differential balun, which is used as the RF and LO balun. 
In this Fig. 3, the single input is applied to the base of 
transistor Q1, and the output is measured between the 
two collectors, which are at the same dc potential. The 
gain of balun is determined by transconductances of Q1, 
Q2, the degeneration inductors L1, L2, and the output 
resistors R1, R2. The amount of the LO suppression is 
determined by the common-mode gain of the balun, and 
the differential-type balun rejects very well the common-
mode gain. The higher the output impedance of the 
current source, the better the LO suppression [3,4]. The 
capacitor C1 separates DC bias from ground. 
Table 1. SiGe HBT DC & AC Characteristics 
Emitter area [ m2] 0.5  6.0  
DC current gain 296 
BVEBO [V] 0.95 
BVCBO [V] 10.7 
BVCEO [V] 3.5 
RC  [ ] 61 
RE  [ ] 30 
   fT [GHz] 41 
   fmax [GHz] 42 
Fig. 2. Architecture of DRSC RF receiver and mixer 
 
Fig. 4 shows a push-pull balun which is composed of a 
common-emitter with degeneration and the common-
collector. The degeneration resistor R3 controls the gain 
of the common emitter path for the same amount of gain 
for both inverting and non-inverting signals, resulting in 
maximum cancellation of LO leakage at the output of the 
balun. R4 is included for output impedance matching. 
The gain of the balun is the sum of the two signal path 
gains [5]. The common-collector path provides highly 
linear performance and the common-emitter is more 
linear than the differential-pair for the same bias current 
and transconductance [4].  
The above baluns are deigned and all integrated on 
chip together with mixer core circuit and provide good 
isolation. 
Double-balanced bipolar mixer in the form of Gilbert 
cell used in this paper is shown in Fig. 5, which is 
differential structure to avoid the common-mode noise. 
When the switching transistors of the Gilbert cell mixer 
are driven fully differentially, theoretically, there is no 
LO leakage at the output. The emitter inductive 
degeneration (L3, L4) is also added to improve linearity. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Fig. 3. RF/LO input balun with bias circuit 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Fig. 4. IF output balun with bias circuit 
IV. FABRICATION AND MEASUREMENTS 
We designed and fabricated the mixer circuit using 0.8 
m SiGe HBT process technology. The manufactured 
mixer photograph is shown in Fig. 6 and this chip size is 
1.9 mm  1.3 mm. In Fig. 6, the upper pad is for supply 
voltage. The left, lower and right center pads are LO 
input, RF input, IF output pads, respectively. 
For this measurement, two RF power sources 
HP83650B, HP83752B, and a spectrum analyzer 
HP8563E were used. The measurement conditions of the 
fabricated mixer were RF=-30 dBm, LO=-5.0 dBm, 
VCC=3.0 V (with local biases VA=3.0 and VB=2.5). Fig. 
On chip 
Down-conversion Mixer 
5.435~5.515 GHz 
5.75~5.83GHz 
LNA IF IF
Filter
LO balun 
IF balun RF balun 
R1 R2 
VO2 
Q1 
VO1 
Q2
L2 L1 
VI1
Q3 
C1
Q5 
VI2 
R4 
VO3
Q4 
VI3 
R3 
11th GAAS Symposium - Munich 2003510
7 shows the measured frequency spectrum at IF output 
port (upper figure: 50 MHz~8.0 GHz range, lower 
figure: 100 MHz span) and conversion gain is 7.5 dB, 
LO to RF port-to-port isolation is 46 dB, LO to IF port-
to-port isolation is 56 dB. Fig. 8 shows the measured IP3 
when the LO input power was fixed to -5.0 dBm and the 
RF input power was swept from –30 dBm to –3 dBm and 
from this figure, IIP3 is –2.5 dBm. Table 2 shows 
comparison of the simulated and measured results. 
-35 -30 -25 -20 -15 -10 -5 0
-60
-55
-50
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
5
P
o
u
t 
[d
B
m
]
Pin [dBm]
 fundamental
 IM3
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Fig. 5. Mixer with emitter inductive degeneration 
 
 
 
   
 
 
 
 
 
 
 
 
 
 
Fig. 6. Photograph of the fabricated mixer 
 
Table 2. The performance of fabricated mixer  
Parameters Simulated Measured 
RF frequency [GHz] 5.810 5.810 
LO frequency [GHz] 5.495 5.495 
Conversion gain [dB] 8.0 7.5 
LO to RF isolation [dB] 68 46 
LO to IF isolation [dB] 43 56 
RF to LO isolation [dB] 56 34 
RF to IF isolation [dB] 40 30 
IIP3 [dBm] 1.5 -2.5 
IC [mA]  20 21 
R6 R5 
VO5 VO4 
Q8 Q10 Q11 Q9 
VI6 
VI7 
Q6 Q7 
L3 L4 VI5VI4 
I1
VA VB VCC 
Fig. 7. The measured frequency spectrum at IF port 
(upper: 50 MHz~8.0 GHz range, lower: 100 MHz 
span) 
IFOUTLOIN 
 
 
RFIN 
 
 
 
 
 
 
 
Fig. 8. The measured IP3 characteristics 
V. CONCLUSION 
DSRC provides high speed radio link between Road 
Side Equipment (RSE) and On-Board Equipment (OBE) 
within the narrow communication area and most of all 
ITS services will be provided by DSRC communication. 
In this paper, a 5.8GHz down-conversion mixer for 
11th GAAS Symposium - Munich 2003 511
DSRC receiver was designed and fabricated using 0.8 
m SiGe HBT process technology and RF/LO matching 
circuits, RF/LO input balun circuits and IF output balun 
circuit were all integrated on chip. The measured 
performance was 7.5 dB conversion power gain, -2.5 
dBm input IP3, 46 dB LO to RF isolation, 56 dB LO to 
IF isolation, current consumption of 21 mA for 3.0 V 
supply voltage. 
 
ACKNOWLEDGMENTS 
This work was supported by the Ministry of Information 
and Communication, Republic of Korea. 
 
REFERENCES 
[1] H. Oh, C. Yae, D. Ahn, and H. Cho, “5.8 GHz 
DSRC Packet Communication System for ITS 
Services,” IEEE Vehicular Technology Conference, 
pp. 2223-227, Fall 1999. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
[2] S.-Y. Lee, H.-S. Kim, S.-H. Lee, K.-H Shim, J.-Y. 
Kang, M.-K. Song, “The behavior of Ti silicidation 
on Si/SiGe/Si base and its effect on base resistance 
and fmax in SiGe hetero-junction bipolar 
transistors,” Journal of Materials Science: Materials 
in Electronics, vol. 12, no. 8, pp. 467-472, August 
2001. 
[3] R.A. Gayakwad, OP-Amps and Linear Integrated 
Circuits, Prentice-Hall, Inc., 1988. 
[4] K.L. Fong and R.G. Meyer, “High-Frequency 
Nonlinearity Analysis of Common-Emitter and 
Differential-Pair Transconductance Stages,” IEEE 
Journal of Solid-State Circuits, vol. 33, pp. 548-555, 
April 1998. 
[5]  D.-Y. Kim, S.-G. Lee, J.-H. Lee, “Up-Conversion 
Mixer for PCS Application using Si BJT,” IEEE 2nd 
International Conference on Microwave and 
Millimeter Wave Technology Proceedings, pp. 424-
427, 2000. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
11th GAAS Symposium - Munich 2003512


A 5.8 GHz Mixer using SiGe HBT Process

Crossref

A 5.8 GHz Mixer using SiGe HBT Process Sang-Heung Lee, Ja-Yol Lee, Seung-Yun Lee, Chan Woo Park, Sang Hoon Kim, Hyun-Chul Bae,           Jin-Yeong Kang, and Kyoung-Ik Cho SiGe Devices Team, Electronics and Telecommunications Research Institute, Republic of Korea  Abstract  — DSRC provides high speed radio link between Road Side Equipment and On-Board Equipment within the narrow communication area. In this paper, a 5.8 GHz down-conversion mixer for DSRC communication system is designed and fabricated using 0.8 Pm SiGe HBT process technology and  RF/LO matching circuits, RF/LO input balun circuits and IF output balun circuit are all integrated on chip. The measured performance is 7.5 dB conversion gain, -2.5 dBm input IP3, 46 dB LO to RF isolation, 56 dB LO to IF isolation, current consumption of 21 mA for 3.0 V supply voltage and the chip size of fabricated mixer is 1.9 mm X 1.3 mm. I. INTRODUCTION ITS (Intelligent Transportation Systems) technology has been developed to solve the traffic problem such as traffic congestion and accidents and reduce the overall congestion cost. The final goal of ITS will be to improve the traffic efficiency and mobile safety without new road construction. DSRC (Dedicated Short Range Communication) provides high speed radio link between Road Side Equipment (RSE) and On-Board Equipment (OBE) within the narrow communication area. DSRC communication system has been developed worldwide and recently applied for Electronic Toll Collection (ETC), but most of all ITS services will be provided by DSRC communication [1]. The SiGe hetero-junction bipolar transistor (HBT) has been considered to be more suitable for RF integrated circuits than the Si bipolar junction transistor (BJT) because its electrical properties, such as current gain, power consumption, small-signal unity-gain frequency, and maximum oscillation frequency are superior to those of the Si BJT [2]. Because of having many advantages for those RF applications, SiGe HBT device has been adopted as a good candidate for manufacturing RF components such as LNAs, Mixers, VCOs, PLLs, RF transceivers. Down-conversion mixers, which convert radio frequency (RF) signal to intermediate frequency (IF) signal, are very important building blocks within a radio system. Their performance affects the performance requirements of the entire system and the performance requirements of other building blocks. In this paper, a 5.8 GHz down-conversion mixer including RF/LO matching circuits, RF/LO input balun circuits and IF output balun circuit for DSRC receiver is designed and fabricated on chip, using SiGe HBT process technology of Electronics and Telecommunications Research Institute (ETRI). The measured performance was 7.5 dB conversion power gain, -2.5 dBm input IP3, 46 dB LO to RF isolation, 56 dB LO to IF isolation, current consumption of 21 mA for 3.0 V supply voltage. II. SIGE HBT DC AND AC CHARACTERISTICS Electrical performance parameters of SiGe HBT such as cut-off frequency (fT), maximum oscillation frequency (fmax), minimum noise figure (NFmin) are critically dependent on not only the base thickness, but also the fabrication process. We used RPCVD system to grow base epitaxial layer, and adopted LOCOS isolation to separate device and device terminals. The maximum values of fT/fmax were 41 GHz/42 GHz at VCE = 2V, IC = 1.83mA as shown in Fig. 1. In Table 1, the main DC and AC parameters of HBT with emitter area of 0.5 u 6.0 Pm2 are summarized. Passive elements used in this paper were MIM capacitor, parallel-branch spiral inductor, and resistors composed of metal, emitter poly-silicon, and base poly-silicon.   0.5 1.0 1.5 2.0 2.5 3.0 3.515202530354045f T [GHz]IC [mA] VCE=1 VCE=2 VCE=1 VCE=215202530354045 f max [GHz]              Fig. 1. AC characteristics of SiGe HBT III. SIGE HBT MIXER DESIGN The architectures of DSRC RF front-end receiver and down-conversion mixer in this receiver are shown in Fig. 2. The LNA output and LO output signals go RF single input port and LO single input port of mixer, respectively, and single output signal of mixer goes IF input port. The 5.81 GHz single-ended RF input and the 5.495 single-ended LO input are converted to be differential to feed in the double balanced mixer by use of on-chip active balun. 11th GAAS Symposium - Munich 2003 509Fig. 3 shows the single-input, balanced-output differential balun, which is used as the RF and LO balun. In this Fig. 3, the single input is applied to the base of transistor Q1, and the output is measured between the two collectors, which are at the same dc potential. The gain of balun is determined by transconductances of Q1, Q2, the degeneration inductors L1, L2, and the output resistors R1, R2. The amount of the LO suppression is determined by the common-mode gain of the balun, and the differential-type balun rejects very well the common-mode gain. The higher the output impedance of the current source, the better the LO suppression [3,4]. The capacitor C1 separates DC bias from ground. GTable 1. SiGe HBT DC & AC Characteristics Emitter area [Pm2] 0.5 u 6.0  DC current gain 296 BVEBO [V] 0.95 BVCBO [V] 10.7 BVCEO [V] 3.5 RC  [:] 61 RE  [:] 30    fT [GHz] 41    fmax [GHz] 42 GGGGGGGGGGGGGGGGGGGGGGFig. 2. Architecture of DRSC RF receiver and mixer  Fig. 4 shows a push-pull balun which is composed of a common-emitter with degeneration and the common-collector. The degeneration resistor R3 controls the gain of the common emitter path for the same amount of gain for both inverting and non-inverting signals, resulting in maximum cancellation of LO leakage at the output of the balun. R4 is included for output impedance matching. The gain of the balun is the sum of the two signal path gains [5]. The common-collector path provides highly linear performance and the common-emitter is more linear than the differential-pair for the same bias current and transconductance [4].  The above baluns are deigned and all integrated on chip together with mixer core circuit and provide good isolation. Double-balanced bipolar mixer in the form of Gilbert cell used in this paper is shown in Fig. 5, which is differential structure to avoid the common-mode noise. When the switching transistors of the Gilbert cell mixer are driven fully differentially, theoretically, there is no LO leakage at the output. The emitter inductive degeneration (L3, L4) is also added to improve linearity.                  Fig. 3. RF/LO input balun with bias circuit                 Fig. 4. IF output balun with bias circuit IV. FABRICATION AND MEASUREMENTS We designed and fabricated the mixer circuit using 0.8 Pm SiGe HBT process technology. The manufactured mixer photograph is shown in Fig. 6 and this chip size is 1.9 mm u 1.3 mm. In Fig. 6, the upper pad is for supply voltage. The left, lower and right center pads are LO input, RF input, IF output pads, respectively. For this measurement, two RF power sources HP83650B, HP83752B, and a spectrum analyzer HP8563E were used. The measurement conditions of the fabricated mixer were RF=-30 dBm, LO=-5.0 dBm, VCC=3.0 V (with local biases VA=3.0 and VB=2.5). Fig. On chip Down-conversion Mixer 5.435~5.515 GHz 5.75~5.83GHz LNA IF IFFilterLO balun IF balun RF balun R1 R2 VO2 Q1 VO1 Q2L2 L1 VI1Q3 C1Q5 VI2 R4 VO3Q4 VI3 R3 11th GAAS Symposium - Munich 20035107 shows the measured frequency spectrum at IF output port (upper figure: 50 MHz~8.0 GHz range, lower figure: 100 MHz span) and conversion gain is 7.5 dB, LO to RF port-to-port isolation is 46 dB, LO to IF port-to-port isolation is 56 dB. Fig. 8 shows the measured IP3 when the LO input power was fixed to -5.0 dBm and the RF input power was swept from –30 dBm to –3 dBm and from this figure, IIP3 is –2.5 dBm. Table 2 shows comparison of the simulated and measured results. -35 -30 -25 -20 -15 -10 -5 0-60-55-50-45-40-35-30-25-20-15-10-505Pout [dBm]Pin [dBm] fundamental IM3                   Fig. 5. Mixer with emitter inductive degeneration                 Fig. 6. Photograph of the fabricated mixer  Table 2. The performance of fabricated mixer  Parameters Simulated Measured RF frequency [GHz] 5.810 5.810 LO frequency [GHz] 5.495 5.495 Conversion gain [dB] 8.0 7.5 LO to RF isolation [dB] 68 46 LO to IF isolation [dB] 43 56 RF to LO isolation [dB] 56 34 RF to IF isolation [dB] 40 30 IIP3 [dBm] 1.5 -2.5 IC [mA]  20 21 GGGGGGGGGGGGGGGGR6 R5 GVO5 VO4 GGGQ8 Q10 Q11 Q9 VI6 GGGVI7 GGQ6 Q7 L3 L4 VI5VI4 GGGI1GGGGGGVA VB VCC GGFig. 7. The measured frequency spectrum at IF port (upper: 50 MHz~8.0 GHz range, lower: 100 MHz span) IFOUTLOIN   GGGGRFIN GG       Fig. 8. The measured IP3 characteristics V. CONCLUSION DSRC provides high speed radio link between Road Side Equipment (RSE) and On-Board Equipment (OBE) within the narrow communication area and most of all ITS services will be provided by DSRC communication. In this paper, a 5.8GHz down-conversion mixer for 11th GAAS Symposium - Munich 2003 511DSRC receiver was designed and fabricated using 0.8 Pm SiGe HBT process technology and RF/LO matching circuits, RF/LO input balun circuits and IF output balun circuit were all integrated on chip. The measured performance was 7.5 dB conversion power gain, -2.5 dBm input IP3, 46 dB LO to RF isolation, 56 dB LO to IF isolation, current consumption of 21 mA for 3.0 V supply voltage.  ACKNOWLEDGMENTS This work was supported by the Ministry of Information and Communication, Republic of Korea.  REFERENCES [1] H. Oh, C. Yae, D. Ahn, and H. Cho, “5.8 GHz DSRC Packet Communication System for ITS Services,” IEEE Vehicular Technology Conference, pp. 2223-227, Fall 1999.                                          [2] S.-Y. Lee, H.-S. Kim, S.-H. Lee, K.-H Shim, J.-Y. Kang, M.-K. Song, “The behavior of Ti silicidation on Si/SiGe/Si base and its effect on base resistance and fmax in SiGe hetero-junction bipolar transistors,” Journal of Materials Science: Materials in Electronics, vol. 12, no. 8, pp. 467-472, August 2001. [3] R.A. Gayakwad, OP-Amps and Linear Integrated Circuits, Prentice-Hall, Inc., 1988. [4] K.L. Fong and R.G. Meyer, “High-Frequency Nonlinearity Analysis of Common-Emitter and Differential-Pair Transconductance Stages,” IEEE Journal of Solid-State Circuits, vol. 33, pp. 548-555, April 1998. [5]  D.-Y. Kim, S.-G. Lee, J.-H. Lee, “Up-Conversion Mixer for PCS Application using Si BJT,” IEEE 2nd International Conference on Microwave and Millimeter Wave Technology Proceedings, pp. 424-427, 2000.                             11th GAAS Symposium - Munich 2003512

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A 5.8 GHz Mixer using SiGe HBT Process

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