AMiBA PROJECT WEEKLY
MEETING MINUTES
Date: 22 February 2001
Participants:
K.Y. Lo, H. Wang, W. Warwick, M.Sinclair, M.T. Chen, H.C. Lu, Y. J. Hwang, R.
Wei, W. Ho, Homing Jiang,
P.
Shaw, Jean Cheng
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Issues and Description |
Action by |
Output
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MMIC |
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1.
Regarding the HPF purchasing issue, Leo has contacted the supplier,
and is waiting for their quotation. 2.
As for purchasing the InP HEMT & HBT MMIC foundry run from TRW,
Huei has sent a schedule plan to TRW, and Paul also sent information to TRW
for NDA preparation. The purchasing process as Stracy Bui of TRW told Huei,
we need to sign a NDA first; TRW will quote after, and then finally sign a
contract. Bui said that the export license would be not sent to us until that
contract signed. 3.
Regarding
whether we could use those InP HEMT & HBT MMIC chips on the multipliers
for prototype lag correlator and on the post amplifiers for prototype
receiver, we should go ahead asking TRW. Warwick will draft out a letter, and
forward it to Mal and Huei to read. Huei will also send a letter to TRW
asking whether we could share the InP activities result with JPL to fabricate
the LNA for AMiBA. 4.
Good news from Todd, Huei says that JPL agrees to loan four LNA to us
if those LNA are directly shipped to Hawaii site for prototype testing.
According the test data provided by Todd, it seems better than the one
purchased from NRAO. Huei will forward
the test data to everyone to look, and collect more test data from Tadd. 5.
Fred says that doing all the testing and putting
together things in Hawaii will help a lot, because we don't need ship back
and forth between US and here, and that’s means we need to get a space to set
up a lab in Hawaii. He asks Mingtang
to list out what we need; how much space? What kind of instruments? And see
what we can do.
6.
Mingtang has talked to the designer of w-.band LNA while he visiting
NRAO by last week, and the design engineer said to him that it is difficult
to low down the noise temperature of that LNA further more. Science they only
have two technicians in lab to make the w-band amplifiers, so they probably
need one and half year to make 40 units of amplifiers. Fred says that the MIC
amplifiers will be a back up to the MMIC amplifiers, since the MMIC amplifier
will be $10k USD cheaper than NRAO amplifier per each. 7.
T.H. got some opinions back from Spacek on the measurement set up;
Eugene & Mingtang have checked the power level of the analyzer last
night. They will put an external attenuator during measurement and make
calibration including the attenuator itself to low down the input power to
the amplifier; they will re-measure that amplifier ASAP. Eugene says. 8.
Eugene says that he is still waiting for more information of the
mixer & HPF from Russian firm. Since Mal already agreed to use their
design on the HPF for AMiBA, so Eugene will find a way to get the Russian
firm’s quotation according to the drawing designed by Mal and his
colleague. 9.
As an
alternative, Mal will modify the packaging design of the InP mixer module for
the Sub-harmonic mixer application. Mal says that in the next week while
Mingtang visit here, he will get some drawings together for that mixer, and
see what they can do for prototype. Eugene says that the module packaging for the prototype is
ok, but for reducing the space of the whole module, it is better to put a LO
input wave guide flange, and connect into the 3 dB coupler which is in the
rectangular form. If we continue to use a connector for the LO input, then we
will need a lot of transition. So he plans to run a 42 GHz LO in wave-guide,
and this will save money and reduce space. 10. Eugene and
Mingtang will visit Chungshang tomorrow afternoon to discuss the sub-harmonic
mixer packaging as well as the w-band feed horn fabrication. 11. Mingtang and
Eugene will contact the Chungshang Institute to discuss the packaging issue
for the Sub-harmonic mixer chips. And in the mean time, Mingtang will
investigate the machining capability of the workshop in Chungshang. Since the
OMT we are going to use, there is a lot of machining work on that, and
Chungshang will be an alternative source for machining. 12. Huei says that
there will be no wafer run for the 0.1um GaAs HEMT chips, and this will not
effect the prototype fabrication. We will use the 0.15um GaAs HEMT chip, which
designed, by Eugene, and Eugene will make a small tuning on that design in
order to get some improvement. Huei says that they are going to make another
design for the LO 42 GHz amplifier, probably put it in the 0.15um GaAs run by
September. |
H.C. Lu W.Wilson H. Wang M.T. Chen Y.J. Hwang T.H. Chu Y.J.Hwng M.T.Chen M. Sinclair Y.J. Hwang M.T. Chen Y.J. Hwang M.T. Chen Y.J. Hwang Y.J. Hwang |
Ongoing Action Item Action item Action item Ongoing Ongoing Action item Ongoing Ongoing Ongoing |
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Lag Correlator Hybrid |
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1.
A model of GaAs HBT from CIC /Taida has been sent to ATNF/Paul
Robert. 2.
Regarding the InP HBT multipliers, Warwick says a series of testing will
be done in a couple of days. Huei asks Warwick to help to test the chip from
a semi-conductor manufacturer by middle March, and Warwick agrees to check
the lab program to see whether possible or not. 3.
Warwick says that the final packaging for lag correlator is a very
tricky issue, so all he can says is he is looking for an individual option at
this moment. But there is not obvious path to go, and require a little bit of
investigation to find out exactly what a way to go. 4.
Regarding how to fit the prototype measurement with two correlators
instead of four, Mike will bring this issue to the science meeting, Fred will
follow up as well. 5.
Regarding the 16-element correlator basis on mixer using power
divider circuit, Jeff says they are continuing to test the individual mixer
using noise source. now they are going to measure the stability of the
output, but they don’t have sensitive enough equipment to see the fluctuation
of the output. So they will add the LNA to the output, and see if they can
measure on that. In mean while, he is still waiting for out put of the
producer for lag correlator, he will keep on pushing them. Jeff will be gone
in the next two weeks to south pole, so he hopes something comes out when he
backs. |
P. Robert W.Warwick W.Warwick W.Warwick M.Kesteven W.Warwick J.Peterson |
Ongoing Ongoing Ongoing Ongoing Ongoing |
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Receiver |
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1.
Mingtang is working on the material evaluation for receiver vacuum
window, he has tested various dielectric material with the HP8510c vector
network analyzer, which including ZOTEFOAM PPA-30 provided by Jeff, DYLITE
provided by Mal, Mylar and Teflon. The a.m. test result has been sent to
everyone to look 2.
Regarding the circular polarization issue, Mal will make a model
according the information from Jeff. 3.
Mingtang says that they almost finish the LO components layout
arrangement, and now they are doing the thermos connection inside the dewar. 4.
Mingtang says that they only went over the testing for the OMT of
Q-band in the last week, since the test instrument for W-band was broken
down. He will keep on talking with NRAO people to settle down the
corroboration proposal - designing and machining by NRAO, packaging and
testing by us. |
M.T. Chen M. Sinclair M.T.Chen M.T. Chen |
Ongoing Ongoing Ongoing Ongoing |
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IF/LO |
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1.
Regarding the over-order fiber laser system, Eugene will inform the
maker that we would like to delete a unit from our order, and ATNF will take
over that one and buy from them according the original price without extra
charge. Eugene will ask the maker to send a quotation to Warwick as well. In
the mean time, Paul will proceed the change order procedure with Taida
accordingly. 2.
As to purchasing the optical fiber, Eugene will figure out the
quantity we need. He will directly contact the Smithsonian people to see
whether they could help us or not. Eugene received some cable information
from Mal; Leo is working on that. 3.
As to the IF amplifier, Leo says that T.H. plans
to use the chip form from HP, and he try to bind that chip by themselves. Warwick is concerning about the output
power capability; he says that what we need for the LO amplifier is about ± 20dBM, and the HP one is only about 10dBM. Leo will discuss this issue with T.H.
later. 4.
Regarding the design on Q- band sub- harmonic mixer, Eugene will make
a back up plan for using the 0.15 um GaAs chip instead of the 0.1um GaAs
chip. But for prototype, we will use the commercial module mixer integrated
with the photonic mixer chips. |
Y.J.Hwang. P. Shaw Y.J.Hwang H.C. Lu T.H. Chu |
Ongoing Ongoing Action item |
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Platform/Mount/Dishes |
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1.
Bob has sent out a revised specification of mount & platform, a drawing
of mount and some revised drawings of small dish to everyone to look. At
pleasant, he is traveling to Germany to work with Vertex on the feasibility
study about hexapod mount vs. conventional mount after that he will come and
stay here from Feb. 26 to March 10. 2.
Mingtang will
bring the revised mount and platform specification as well as the mount
drawing to the Chungshang Institute tomorrow afternoon. Paul will forward
that revised information to Mike, and ask him to get a new offer from the
Sidney Engineering Co. |
P. Raffin B. Martin B. Martin M.T. Chen. P.Shaw |
Ongoing Ongoing Action item |
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General issues |
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3.
Fred says that for every two week, now we have a coordination meeting
with Bob, Warwick, Mike, Tzi-hong, Paul and he specifically to go over
coordination issues. One issue was pointed out by Warwick is that the often
time we make the decision and not announce properly or often we don't make
Decision; the mount is an example, went from one 10 meters to three 2 meters,
and now by 6 meter, we saw what happen, but we don't really know what exactly
we are doing. Right now because of the cost reason mainly back to 6 meters.
He finally got a report from Tzi-hong on behalf on the science team, from
scientific examination of this issue, eventually conclusion is the 6 meters
is ok. He will send that around for comment. As to the 6 meters mount, Bob of
course will talk to Vertex, and we are going to send the revised specs to the
Chungshang Institute, and see what they can do. We should try to get the
company in Australia to take a look also. 2.
Fred says that we are approaching the end of the first year and the
beginning of the second year, he would like to take this opportunity to go
over again at least the coordination level, some more detail on work
packages, the project block into. Bob will be stay here about 10 days, Fred
hope during that time, Bob will sit down and go over all the package in
detail everybody here. We hope Bob could work out a work plan for mount and
platform at that time as well. We really need to look at the cost what we
have, he hopes Bob here in a week or so will start that process. Regarding
the time schedule for prototype, it seems is not clear what exactly in our
mind. So after this phone call, Fred will draft something and send it out
around to make it clear. |
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Traveling |
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Mingtang
visiting ATNF by Feb.27 ~ March 4 |
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Next Meeting |
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7:30pm EDT,
8:30am Taiwan, 10:30 Australia, 4:30pm Tucson/Thursday/March 01, 2001 |
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