NRC Publications Archive
Archives des publications du CNRC
Extremely low noise UHF-band amplifiers for square kilometer array
Jiang, Nianhau; Garcia, Dominic; Niranjanan, Pat; Halman, Mark; Wevers,
Ivan
This publication could be one of several versions: author’s original, accepted manuscript or the publisher’s version. /
La version de cette publication peut être l’une des suivantes : la version prépublication de l’auteur, la version
acceptée du manuscrit ou la version de l’éditeur.
For the publisher’s version, please access the DOI link below./ Pour consulter la version de l’éditeur, utilisez le lien
DOI ci-dessous.
Publisher’s version / Version de l'éditeur:
http://doi.org/10.1117/12.2232154
Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for
Astronomy VIII, 2016-06
NRC Publications Record / Notice d'Archives des publications de CNRC:
http://nparc.cisti-icist.nrc-cnrc.gc.ca/eng/view/object/?id=5104483b-ca3a-432e-a98b-c3aec5cd2d57
http://nparc.cisti-icist.nrc-cnrc.gc.ca/fra/voir/objet/?id=5104483b-ca3a-432e-a98b-c3aec5cd2d57
Access and use of this website and the material on it are subject to the Terms and Conditions set forth at
http://nparc.cisti-icist.nrc-cnrc.gc.ca/eng/copyright
READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE.
L’accès à ce site Web et l’utilisation de son contenu sont assujettis aux conditions présentées dans le site
http://nparc.cisti-icist.nrc-cnrc.gc.ca/fra/droits
LISEZ CES CONDITIONS ATTENTIVEMENT AVANT D’UTILISER CE SITE WEB.
Questions? Contact the NRC Publications Archive team at
[email protected]. If you wish to email the authors directly, please see the
first page of the publication for their contact information.
Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la
première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n’arrivez
pas à les repérer, communiquez avec nous à [email protected].
Extremely low noise UHF band amplifiers
for square kilometer array
Nianhua Jiang*, Dominic Garcia, Pat Niranjanan, Mark Halman, Ivan Wevers
NRC Herzberg, National Research Council Canada
5071 West Saanich Road, Victoria, B.C. Canada V9E 2E7
ABSTRACT
This paper demonstrates two designs of extremely low noise amplifiers in the low frequency range of 350 MHz to 1070
MHz. Hybrid microwave integrated circuit is adapted for a low noise design at this low frequency range. Discrete
passive components with high-Q and large values are selected to integrate with the best low noise transistors to optimize
the LNA performance. The first UHF band cryogenic LNA was designed with InP HEMTs in all three stages for Square
Kilometer Array - mid telescope band-1 receiver. This LNA extended the low end frequency to 350 MHz, and achieved
averaging 1.4 Kelvin of a record low noise temperature, more than 47 dB gain, and good input and output return losses <
-10 dB over the broad bandwidth from 350 to 1050 MHz at 15 K. The second UHF band cryogenic LNA was developed
for MeerKAT Array, a precursor of Square Kilometer Array. This LNA was designed with InP HEMT transistor at first
stage to achieve best low noise performance and GaAs HEMTs for second and third stages to replace InP HEMTs and
realize high gain and good amplitude stability at cryogenic temperature. The second LNA achieved a record low noise
temperature of averaging 0.6 Kelvin, more than 45 dB gain, and good input and output return losses ≤ -12 dB over the
wide bandwidth from 580 to 1070 MHz at 15 K.
Keywords: Low noise amplifier, cryogenic LNA, radio telescope receiver, square kilometer array, InP HEMT, UHF
band LNA, hybrid microwave integrated circuit, MeerKAT.
1. INTRODUCTION
In radio astronomy scientists always demand the state-of-the art low noise and wideband receivers. With technology
advancing and design tools improving, RF engineers can speed up the design cycle and realize the optimal design and
better receiver performance. The Square Kilometer Array (SKA)1 project is an international effort to build the world’s
largest radio telescope with a square kilometer of signal collecting area. MeerKAT array2 as a precursor of SKA is under
construction currently, and will be integrated into the mid-frequency component of SKA Phase 1. The MeerKAT array
will have 64 interlinked receptors--complete antenna structures, made up of the 13.5 m effective diameter main reflector
and a 3.8 m diameter sub-reflector. The SKA will be the most powerful, sensitive and largest radio telescope ever
constructed.
The performance of RF receiver systems is limited by noise. RF receiver noise temperature can be misleading without
defining the receiver’s physical temperature. The receiver noise temperature is an equivalent temperature that the
receiver produces that amount of noise power into signal at the given physical operating temperature. All of
materials/components generate noise at a power level proportional to the physical temperature of the materials
/components. An amplifier is made of active and passive components. All of these components produce noise. RF
receiver sensitivity is dependent on not only the receiver noise temperature, but also the receiver noise floor level. When
the signal amplitude is lower than the receiver noise floor, it is difficult to pick up the signal buried under noise floor.
The RF receiver/amplifier noise can be broken down into thermal noise, electronic noise, and impedance mismatch noise.
The thermal noise is proportional to the detector’s physical temperature.
The thermal noise power spectrum density:
*[email protected];
log
phone 1+250-363-3409;
dBm/Hz
fax 1+250-363-0049
Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VIII,
edited by Wayne S. Holland, Jonas Zmuidzinas, Proc. of SPIE Vol. 9914, 991420
© 2016 SPIE CCC code: 0277-786X/16/$18 doi: 10.1117/12.2232154
Proc. of SPIE Vol. 9914 991420-1
Downloaded From: http://proceedings.spiedigitallibrary.org/ on 08/16/2016 Terms of Use: http://spiedigitallibrary.org/ss/termsofuse.aspx
(1)
Where k = 1.38 × 10-23 J/K Boltzmann’s constant; T = temperature in Kelvin.
dBm/Hz,
at T = 300 K
(2)
Any of the instruments such as Vector Network Analyzer, Spectrum Analyzer, RF power meter, etc., can’t have lower
noise floor than the above value at room temperature. When cooling the receiver down to 15 K, the thermal noise power
will drop significantly as follows:
dBm/Hz, at T= 15 K
(3)
The thermal noise power will decrease by 13.01 dB when cooling the receiver to 15 K from 300 K. This is equivalent to
reduce 13.01 dB noise figure (NF) in the receiver noise floor at 15 K. The noise floor increase in temperature from 15 K
to 300 K can be calculated as in (4).
= 15× (
K
(4)
Obviously one can see the noise floor difference between cryogenic temperature 15 K and room temperature 300 K. For
achieving extremely low noise performance, cooling the devices/amplifiers to cryogenic temperature is the efficient way
to reduce the thermal noise power, which is not just to improve the receiver noise performance but also lower the
receiver noise floor significantly. In other words, if two RF receivers have the same noise temperature measured at 300
K and 15 K respectively, they will have 285 K difference in their receiver noise floors. The noise floor is dependent on
their physical temperatures. This is why all of the state of the art radio astronomy telescopes have the cryogenically
cooled RF receivers.
For modern radio telescopes, there are two approaches to improve the system sensitivity. One is to build bigger and
bigger antenna dishes, and larger and larger array to increase the signal collecting area. Another is to develop extremely
low noise receivers operating at cryogenic temperature to lower the receiver noise temperature and noise floor. The first
approach will drive the cost exponentially as the dish size and array get larger. As the RF receiver cost is a fraction of the
telescope, the second approach is a more cost effective way to improve the telescope system sensitivity and efficiency.
A low noise amplifier(LNA) is the key components as a preamplifier in the RF receiver. It will dominate the receiver
noise, sensitivity, and even system efficiency. The input return loss of LNA is one of the key parameters, especially in
radio astronomy receivers. Bigger dishes and larger arrays are being built to increase the collecting area of the distant
and faint signals from the sky. When LNA has a poor input return loss, the collected signals will be reflected back out to
the sky at the input of LNA. Some portion of the valuable information is thrown away after being collected by the large
antenna array. Obviously, the preamplifier has to have very low noise and as low input return loss as possible. Most of
the low noise amplifiers published to date are operating above 1 GHz3,4,5,6,7. When the frequency gets lower, the passive
components values of LNAs’ circuit become larger. This creates a big challenge to the design and implementation.
2. InP HEMT MODEL
Indium phosphide based high electron mobility transistors (InP HEMT5) have superior performance in high-speed and
low noise application. Due to the outstanding cryogenic performances, InP HEMTs are well suited for low noise
amplifier and low power application in cryogenically cooled receivers for radio astronomy and deep space missions. The
small-signal equivalent circuit diagram of the InP HEMT model used at 15 K in this work is shown in Figure 1. The
values of the intrinsic and extrinsic components of InP HEMT model are listed in Table 1.
Table 1. Component values of InP HEMT model.
Cgs, Rgs Cds Rds Cgd Rgd g m mS
Lg nH
Rg Ld nH
Rd Ls nH
Rs 240 0.7 50 31.7 54 5 150 17 0.5 18 1.5 5 1 fF fF fF Cpgs Cpgd Cpds fF fF fF 8 3.5 Proc. of SPIE Vol. 9914 991420-2
Downloaded From: http://proceedings.spiedigitallibrary.org/ on 08/16/2016 Terms of Use: http://spiedigitallibrary.org/ss/termsofuse.aspx
25 Td K 453 Lg
Figure 1. Small signal equivalent circuit of InP HEMT with 100 nm gate length and 280 µm gate width at 15 K.
All of the noise sources in transistors must be taken into account for very low noise applications. As one can see in
Figure 1, there are many resistors to represent the property of elements/materials as intrinsic and extrinsic nature. All of
these resistors become the thermal noise sources in the transistor. As mentioned previously, cooling the devices is the
best or exclusive way to minimize the thermal noise sources. In order to reduce the shot noise associated with bias
current, leakage current at the gate and drain, LNA should be designed and optimized for low power operation.
3. DESIGN AND SIMULATION
As the first gain block, LNAs always play a critical role in the overall performance of the receiver. The considerable
challenge for LNA design is to simultaneously realize minimum noise impedance matching and good input return loss at
the wide frequency range. The design of LNA comprises bandwidth, low noise figure, high gain, gain slope, gain
compression, low return losses at the input & output over the entire operational frequency range, and unconditional
stability beyond the operational frequency range. LNA has to be stable even if the source and load impedances are
equivalent to open or short termination at the outside of the operational band width. Although all of noise temperature,
gain, return losses at the input & output, and stability are equally important, they have complicated correlation and do not
always work in each other’s favor. Sometimes, parameter trade-offs are necessary.
InP HEMTs exhibit very low noise figure and high gain, excellent performance especially at cryogenic temperature3,4,5.
For operating at the very low frequency (UHF band), transistors with large gate width and moderate gate length are
preferred. The gate length is critical to low noise performance and LNA stability. Extremely short gate length means
higher gate resistance, therefore adds excess noise at the gate. For shorter gate lengths, it is more difficult to stabilize the
transistor at wide frequency range. FETs have very high impedance at the gate. This leads to the complexity in
transforming the high impedance to 50 Ohm characteristic impedance and getting the noise down to the transistors’
minimum noise. Large gate width can increase the capacitance at the gate and drain, increase the transconductance, and
improve the gain compression. Large size transistors are preferred for UHF band LNA design. InP HEMTs with 100 nm
gate length and 280 µm gate width are selected for these cryogenic UHF band LNAs. The input and output impedances
of the InP HEMT are plotted in Figure 2 and 3.
As shown in Figure 2, there are a real part of Z11 with 15 Ohm up to 4 GHz and an image part of Z11 with highly
capacitive reactance at the gate, which is a big difference from 50 Ohm. The capacitive reactance varies with frequency,
which increases dramatically as frequency decreases below 1000 MHz, and reaches to a level value above 2.5 GHz. In
order to transform this highly capacitive reactance to 50 Ohm impedance, a large inductance value is required at UHF
Proc. of SPIE Vol. 9914 991420-3
Downloaded From: http://proceedings.spiedigitallibrary.org/ on 08/16/2016 Terms of Use: http://spiedigitallibrary.org/ss/termsofuse.aspx
band. This presents considerable difficulty to design a LNA working at this low frequency range and having a minimum
noise matching and a low input return loss simultaneously.
K
50
o
45
350
40
900
35
-1350
30
1800
25
-2250
20
-2700
15
10
-Re(Z22) -Im(Z12)
0
0
500
1000
1500
2000
2500
3000
3500
100
O
90
-3
80
6
70
9
60
-12
50
15
40
18
-3150
30
21
3600
20
-4050
10
-4500
4000
o
N
ryrv
E
E
24
-Re(Z22) -Im(222)
27
30
O
Frequency (MHz)
500
1000
1500
2000
2500
3000
3500
4000
Frequency (MHz)
Figure 2. Real and image of the input impedance of InP HEMT.
Figure 3. Real and image of the output impedance of InP HEMT.
The Gamma optimum ( opt) of InP HEMT that represents the terminating impedance at the input of the transistor for a
minimum noise performance, and the conjugate S11 of InP HEMT are shown in Figure 4. opt is usually different from
the conjugate S11. This means that the minimum noise matching and the optimal input return loss of LNA can’t be
achieved simultaneously.
S*11
op
1=ñ
0
úrn
freq (100.0MHz to 30.00GHz)
Figure 4. Gamma optimum ( opt) and conjugate S11 of InP HEMT as function of frequency.
It should be noted that a transistor is a 3-port complex network. Gate impedance is sensitive to the source circuit. A
source inductance feedback can rotate S*11 closer to opt, which can help in obtaining close to the minimum noise figure
and respectable input return loss simultaneously. Although this inductive degeneration does not seriously impact the
noise performance, the additional source inductance provides negative series feedback increasing with frequency.
Therefore it can reduce the overall available gain of the transistor and make the gain slope negative. The total gain and
gain slope can be balanced in the succeeding stages.
In practice, LNAs have multi-stage transistors cascaded to achieve high gain and broad bandwidth. A further
complication in LNA design is the inter-stage impedance matching between the cascaded transistors. Careful design of
the inter-stage circuits to match the transistor output (low impedance) to the input (high impedance) of the cascaded
Proc. of SPIE Vol. 9914 991420-4
Downloaded From: http://proceedings.spiedigitallibrary.org/ on 08/16/2016 Terms of Use: http://spiedigitallibrary.org/ss/termsofuse.aspx
transistor can improve the bandwidth, gain, and gain flatness. The configuration of cascaded multi-stage transistors
provides more freedom in tuning parameters to optimize the performance, and make trade-offs among the noise, return
losses at the input and output, gain, gain slope, linearity, and stability.
As one can see in Figure 3, the drain has a small capacitive reactance increasing with frequency, and resistance
decreasing from 85 Ohm to 57 Ohm from 100 MHz up to 4 GHz. This makes it relatively easy to do good impedance
matching to 50 Ohm at the output of LNA compared at the input. An additional resistor, inductor, and capacitor, either in
series or parallel, are needed at the drain of the transistor to maximize the gain, bandwidth, and stabilize the circuit by
impedance matching. The output matching at the last stage transistor is critical to the gain compression of LNAs. The
optimal gain impedance matching does not correspond to the optimal gain compression point. The output matching
circuit has to be realized by means of a trade-off.
The advances in MMIC technology, combined with computational circuit simulation technique and comprehensive
electromagnetic modelling of components and devices, made it possible for the amplifier design to realize octave or even
decade frequency bandwidth, and extremely low noise performance. MMIC technology is very suitable for design and
fabrication of high frequency amplifiers. As the frequency decreases below 2 GHz, the wavelength becomes very long.
The amplifier matching circuits need large inductance and capacitance values for passive components. The passive
components get bigger in size. The inductors especially become too big to fabricate on a MMIC chip. In fact, MMIC
foundry has a limit on the max values of passive components, such as inductor, capacitor, and resistor. In order to
minimize the noise source, the amplifier design needs to use inductive and capacitive components, and avoid using
resistive components in matching circuits as much as possible.
Figure 5 shows the simulated results of gain and noise temperature with two designs of UHF LNAs at 15 K. UHF LNA-I
was designed with 3-stage InP HEMTs for SKA-mid telescope band 1 receiver in the bandwidth from 350 MHz to 1050
MHz. The simulation verified that it was difficult to push down to below 500 MHz due to the gate impedance changing
quickly with frequency. UHF LNA-II was designed for MeerKAT UHF band receiver with bandwidth from 580 MHz to
1070 MHz. This UHF LNA was designed with InP HEMT transistor at first stage to achieve best low noise performance
and GaAs HEMTs for second and third stages to replace InP HEMTs and realize high gain and good amplitude stability
at cryogenic temperature. Both of these designs indicate about 1.0 Kelvin extremely low noise temperature and more
than 45 dB high gains. Figure 6 illustrates the input and output return losses of the two UHF LNAs designs at 15 K. As
one can see, the two designs show better than -10 dB low return losses at both inputs and outputs. As mentioned
previously, it is relatively easy to design a better return loss at output than at input because the transistor has low output
impedance close to 50 Ohm in the wide frequency range.
10
50
10
45
9
45
9
40
8
40
8
35
7
35
7
6
30
6
25
5
4
50
30
:52;
25
5
m
:2'
0 20
4
V 20
15
3
15
3
2
10
2
10
5
5
0
0
03
04
0.5
0.6
0.7
0.8
09
0
05
0.6
0.7
08
0.9
1.1
Frequency (GHz)
Frequency (GHz)
Figure 5. Simulated noise temperature and gain of UHF LNA-I with a band ratio of
3:1 on left, and UHF LNA-II with a band ratio of 2:1 on right at 15 K.
Proc. of SPIE Vol. 9914 991420-5
Downloaded From: http://proceedings.spiedigitallibrary.org/ on 08/16/2016 Terms of Use: http://spiedigitallibrary.org/ss/termsofuse.aspx
12
5
5
I
-522
-S11
0
I
I
0
-5
m
-5
a
N
-10
-10
1
E -15
i
-15
cc
-20
-20
-25
-25
-30
-30
03
0.4
0.6
0.5
0.7
0.8
0.9
1
11
0.4
1.2
0.5
0A
0.7
0.9
0.8
1
12
1.1
Frequency (GHz)
Frequency (GHz)
Figure 6. Simulated input and output return losses of UHF LNA-I with a band ratio of
3:1 on left, and UHF LNA-II with a band ratio of 2:1 on right at 15 K.
4. LNA PERFORMANCE
Two UHF LNAs were built with hybrid technology. They were tested in a closed cycle cryostat under cryogenic
temperature 15 K. The noise temperature and gain of two UHF LNAs were measured with Y-factor technique10 and cold
attenuator method9 as shown in Figure 7. UHF LNA-I achieved 1.4 K averaging noise temperature, more than 47 dB
gain, and return losses (S11 and S22) < -10 dB at 15 K ambient from 350 to 1050 MHz. UHF LNA-II achieved 0.6 K
averaging noise temperature, more than 45 dB gain, and return losses (S11 and S22) < -12 dB at 15 K ambient from 580
MHz to 1070 MHz. The design of UHF LNA-II achieved better noise performance than that of UHF LNA-I. It should be
noted that UHF LNA-I had a wider bandwidth extended to the lower frequency than UHF LNA-II had. As the frequency
band width gets wider, it is more difficulty to make a perfect minimum noise impedance matching. These two UHF
LNAs have 3-stage cascaded transistors and ~ 18 mW DC power consumption.
In the receiver chain, a feed horn or orthmode transducer is connected to the input of LNA, and a filter or mixer is
connected to the output of LNA. The impedance of these components may have very bad match, and can be any values
from 0 to ∞ out of the bandwidth. These mismatches could cause the LNA to become unstable or oscillating in or out of
the bandwidth. As the gain of LNA increases in cryogenic temperature, it becomes increasingly more challenging in
making a design stable. These two UHF LNAs were also checked with 50 ohm, open and short terminations at the LNA
input and output ports to confirm that they were unconditionally stable under cryogenic operation. The low input return
loss (S11) is essential for improving the receiver system efficiency and reducing the standing wave between a feed horn
and LNA. Given the good S11, these two UHF LNAs don’t need an isolator between a feed horn and LNA input port.
Consequently, the receiver can achieve lower noise temperature than the one using an isolator.
11
55
11
10
50
10
4
9
45
9
4
8
40
8
35
7
35
7
[G
30
6
7:0-.
30
6
.c
25
5
a
c
25
w
2
4
20
54
a
v
H
v
l7
15
15
3
10
2
Z
0
Y
ar
2
1
0
0.3
0.4
0.5
06
0.7
08
0.9
1
11
12
o
o
0.5
0.6
Frequency (GHz)
0.7
0.8
09
1
Frequency (GHz)
Figure 7. Measured noise temperature and gain of UHF LNA-I on left, and UHF LNA-II on right at 15 K.
Proc. of SPIE Vol. 9914 991420-6
Downloaded From: http://proceedings.spiedigitallibrary.org/ on 08/16/2016 Terms of Use: http://spiedigitallibrary.org/ss/termsofuse.aspx
5
0
-511 -522
-511
m
-a
N
-S22
-10
sessimare
-15
-20
-5
1C
-10
CC
-15
3
V
-20
-25
-25
03
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
0.4
0S
06
0.8
0.7
09
1
11
1.2
Frequency (GHz)
Frequency (GHz)
Figure 8. Measured return losses at input and output of UHF LNA-I on left, and UHF LNA-II on right at 15 K.
5. LINEARITY and GAIN STABILITY
The essential job of an amplifier is to increase the power level of an input signal without otherwise altering the content of
the signal. This requires the linear relationship across the frequency and amplitude ranges of the signals. Y-factor
technique of the noise measurement is based on the linear performance of the amplifiers and receivers. When a LNA has
non-linear gain, the noise temperature of LNA measured with Y-factor technique can be any of false values. Obviously,
the linearity is an important parameter to evaluate a low noise amplifier for use in radio astronomy applications and
precision test systems. The linearity and 1 dB gain compression of UHF LNA-II was measured at 15 K as shown in the
left of Figure 9. Its 1 dB gain compression is -3.6 dB at the output. Each stage contributed 15 dB gain in average. The
third stage operating point limited the gain compression. If the DC power consumption budget is raised, the gain
compression point of the LNA can be increased.
The gain stability of radio telescope receivers is essential for integrating the distant and faint signals from the sky. The
gain stability of LNA dominates the receiver stability, especially cryogenic receiver with extremely low noise and high
gain performance. The gain stability of UHF LNA-II was measured with Allan Variance method11 at 15 K. An 800 MHz
continuous wave signal of -60 dBm was fed into the LNA input. A power sensor of 18 GHz wideband was used to
measure the signal power at the output of LNA. The power meter was configured with no averaging at a sampling rate of
10 ms interval. The data set was taken in one hour. The Allan Variance was calculated as shown in the right of Figure 9.
This result represented the gain stability of whole test setup including UHF LNA-II, a signal generator, and power
sensor. The gain stability specs of Atacama Large Millimeter Array receivers12 are illustrated for comparison. UHF
LNA-II has very stable gain and achieved Allan Variance better than 1×10-7 from 0.1 to 300 second at 15 K ambient.
1.0E -03
5
o
1.0E -04
-ALMA Spec 1
5
ALMA Spec 2
UHF LNA
1.0E -05
-10
-15
1.0E -06
-20
1.0E -07
-25
-Measured -Linear
1.0E -08
-30
-35
-80
-75
-70
-65
-60
-55
-50
-45
-40
1.0E -09
0.01
Input Power (dBm)
01
1
10
100
1000
Integration Time (s)
Figure 9. Measured linearity and 1 dB gain compression of UHF LNA-II on left, and Allan Variance on right at 15 K.
Proc. of SPIE Vol. 9914 991420-7
Downloaded From: http://proceedings.spiedigitallibrary.org/ on 08/16/2016 Terms of Use: http://spiedigitallibrary.org/ss/termsofuse.aspx
5. SUMMARY
Since the noise performance of the first stage transistor dominates the LNA noise level, InP HEMT is good for the first
stage in LNA design. UHF LNA-II demonstrated that GaAs HEMTs are suitable for second and third stages in the
cascaded circuit configuration. This LNA achieved extremely low noise performance of averaging 0.6 K in the
bandwidth, closing to the physical limit at the cryogenic temperature of 15 K. The hybrid circuit configuration made
UHF LNA-I possible to extend the frequency band lower to 350 MHz, integrate optimal discrete components, and easily
tune the circuit in production. The single-end design with the cascaded 3-stage transistors realized more than 45 dB gain,
wideband impedance match for both minimum noise and respectable return losses at the input and output. The UHF
LNA-II is currently under the production and supplied to MeerKAT team for the receiver system integration.
ACKNOWLEDGEMENT
The authors are particularly grateful to David Loop for his continued support of this research and development.
The authors would like to thank our mechanical group for machining the LNA chassis.
REFERENCES
[1] Square Kilometer Array, https://www.skatelescope.org/
[2] MeerKAT project, http://www.ska.ac.za/meerkat/
[3] Jiang, Frank(Nianhua), Claude, Stèphane and Garcia, Dominic, “Hybrid Cryogenic Low Noise Amplifier for the
MeerKAT Array,” IEEE Xplore ANTEM, 16th International Symposium, July, (2014).
[4] Jiang, Nianhua, Claud, Stèphane e, Yeung, Keith, Garcia, Dominic, “Low noise InP HEMT amplifier,” Proceedings
of SPIE, Ground-based Telescopes, vol. 5489, pp848-857, (2004).
[5] Pospieszalski, Marian W., “Extremely Low-Noise Amplification with Cryogenic FETs and HFETs: 1970-2004,”
IEEE Microwave Magazine pp 62 – 75, Sept., (2005).
[6] Weinreb, Sander, Bardin, Joseph C., and Mani, Hamdi, “Design of Cryogenic SiGe Low-Noise Amplifiers,” IEEE
Transaction on Microwave Theory and Technology, vol. 55, no. 11, Nov. (2007).
[7] Wadefalk, Niklas, Mellberg, Anders, Angelov, Iltcho, Choumas, Emmanuil, Kollberg, Erik, Rorsman, Niklas,
Starski, Piotr, Stenarson, Jörgen and Zirath, Herbert, “Cryogenic 1.5-4.5 GHz ultra low noise amplifier,” IEEE
Transactions on Microwave Theory and Techniques, Apr., (1996).
[8] Jonas, J.L., “MeerKAT—The South African Array With Composite Dishes and Wide-Band Single Pixel Feeds,”
Proceedings of the IEEE, Vol 97, issue 8, pages 1522-1530, (2009).
[9] Fernandez, J. E., “A Noise-Temperature Measurement System Using a Cryogenic Attenuator,” TMO Progress Report
42-135, Nov. 15, (1998).
[10] Agilent Application Note, “Noise Figure Measurement Accuracy – The Y-Factor Method,” Allocation Note 57-2,
http://cp.literature.agilent.com/litweb/pdf/5952-3706E.pdf
[11] Allan, David W., Weiss, Marc A., and Jespersen, James L., “A Frequency-Domain View of Time-Domain
Characterization of Clocks and Time and Frequency Distribution Systems,” Proceeding of the 45th Annual Symposium
on Frequency Control, pp. 667 – 678, (1991).
[12] Claude, Stèphane, Niranjanan, Pat, Jiang, Frank, Duncan, Dave, Garcia, Dominic, Halman, Mark, Ma, Haoling,
Wevers, Ivan, Yeung, Keith, “Performance of the Production Band 3 receiver (84-116 GHz) for the Atacama Large
Millimeter Array (ALMA),” Journal of Infrared, Millimeter, and Terahertz Waves, Volume 35, ISSUE 6-7, pp 563-582,
July, (2014).
[13] Rossi, Filippo, Chiong, Chau-Ching, Wang, Huei, Chen, Ming-Tang, Jiang, Frank, So, Poman, Claude, Stéphane
and Bornemann, Jens, “A Wideband MMIC Low Noise Amplifier with Series and Shunt Feedback,” IEEE Xplore
ANTEM, 16th International Symposium, July, (2014).
Proc. of SPIE Vol. 9914 991420-8
Downloaded From: http://proceedings.spiedigitallibrary.org/ on 08/16/2016 Terms of Use: http://spiedigitallibrary.org/ss/termsofuse.aspx