AMiBA PROJECT WEEKLY MEETING MINUTES

Date: 28/September/2000

Attendants: B. Martin, J. Peterson, W. Warick, H. Wang + 1 student, T.H. Chu, M. Kesteven, H.C. Lu, Eugene Hwang , H.S.Li, P. Shaw, J. Wang

Issues and Description	Action by	Output
MMIC- W- Band InP HEMT LNA
1. Regarding the Sub Hamonic Mixer¡¦s chip test at ATNF, Huei will contact Mal to check the test result of the " isolation property" by early next week. 2. Huei says Todd told him that their mask of InP HEMT MMIC might be delay to the early Dec, so we might have time to work out another design, and he is willing to pay us as well. 3. As for the 0.1um GaAs HEMT, Huei says they had a design review in last Saturday. In the mean time, CIC/Taida keep on negotiating the contract with TRW. 4. As to the export license application for the InP HEMT of TRW, Huei says Joyce told him that the review process is still ongoing at the State Department He is expecting to get a final decision on that issue by early November. 5. Waveguide filter ¡V Mal says that they have been doing some experiments with particular type of sorts there, due to the cut off rate is not sufficient, they need to do some small work on that in a couple of weeks more. He will send some of data to Huei to take a look. 6. As for purchasing the 4 units of 82~106 GHz amplifiers from NRAO, we sent a letter to NRAO for export license application. Once the internal purchasing procedure was completed we will release that order to NRAO. Paul says that the internal purchasing process is still ongoing. 7. Mal sys that their lab will get ready to test the rest of 6 units of w-band InP LNA in a week or two. 8. Prof. Chu says he didn't receive the Specek's amplifiers yet, and the dead line is on this Friday, so he will check the status with the local distributor.	H. Wang H.Wang H.Wang H.Wang M. Sinclair P. Shaw M. Sinclair T.H. Chu	ongoing ongoing ongoing ongoing ongoing ongoing ongoing ongoing
Lag Correlator Hybrid
1. For the 17 lag correlator, Jeff starts the discussion with Gramic about making these tree divider structure that they sent a email about, and we talked about two weeks ago . They like the idea, but suggested that we should make the structure with print resistors on synthetic substrate alumina, and that was discussing on making the entire part on alumina mixer at all instead of using hybrid. The alumina has an advantage of very good loss tangent. So they are discussing it. If it works out the entire lag correlator would be shrink by 3 inches dimension, and that will be very nice if we could achieve that. So that is the discussion they are having. Warwick says that the high dielectric constant is an advantage making things smaller, but the problem is the distortion with the wide bandwidth. He agrees the use of print resistor will be the only way we are able to do it for the 20GHz wide band correlator. And for the other substrates, similar to alumina but having lower dielectric constant, may be not common and a little bit expensive, but might be an option. 2. Warwick says that he is still waiting for the HBT Gilbert Cell multiplier wafers from TRW. 3. Ray Wei says he has simplified the circuit and also completed the simulation for the IC circuit. There are some problem about the frequency mismatch between master PLL and slave VCO, so is trying to solve these problems. After that he will start to design the digital part. 4. Huei says that they will finish the design work on the Gilbert Cells Multiplier in two weeks, if this time that chip could not meet with the design goal, they still have chance to make the second iteration, and to solve the problems by next time.	J. Peterson W. Wilson R. Wei H. Wang	Ongoing ongoing ongoing ongoing
Receiver
1. Mingtang says he is starting the purchasing process for the cold heads and some key components. 2. Yugene says he only got a sheet of specs from the Atlantic Microwave Company about the OMT, they only guarantee the band width of 94~96 GHz. Bob suggests Yugene that he should talk to NRAO people about the OMT while he visiting there by next week, and Bob will follow up that also.	M.T.Chen Y.J. Hwang	ongoing ongoing
LO/IF
1.Eugene says that he prepared some draft block diagrams for photonic LO and photonic calibration source, and he just sent them back to Taipei Jackie will distribute the copies to everybody right after this meeting. 2.Eugene says that as for the photonic LO system ,J. Payne and D¡¦Addario suggested to use the ¡§central unit & distribution¡¨ instead of a conventional one, and this will reduce cost of the whole system. There will be a further discussion with Bill Shallue about the issue of ¡§antenna - side coupled configuration¡¨.	Y.J. Hwang Y.J. Hwang	ASAP ongoing
30 cm antenna
Michael says he spoke to G. James, James is still working on the calculations for the small antennas, and need a little while to work out the number we need, he thinks.	M.Kesteven	ongoing
Platform/mount/dish
Regarding the height of ground shield for our antenna, Bob requests Micelle to ask their expert to verify what size is good for us.	M. Kesteven	ASAP
Site acquisition
Bob says he talked with John Barnes of the Mauna Lao Observatory last week. John is the Station Chief of the MAO operation in Hilo. It sounds very promising that our needs may mesh with what they look for in the use of the site. Bob says he is planning to visit Hilo in November, to take a look at the application process that we need to do. He hopes we could test the prototype over there by next year.	B. Martin	ongoing
Prototype Specification and Project Book
Bob distributed a draft prototype plan to everyone by email on Sep. 27, discussion about this issue in the meeting is summarized as below: l System block diagrams ¡V Leo will update the diagrams in electronic form. l Delay line system ¡V for the prototype, we should leave it off later, since we don¡¦t need it until the construction for all of the three platforms, Bob says. l System overview descriptions ¡V Michael will supply more details on that area. l Receiver ¡V Bob will ask Mingtang to add the layout drawings to the receiver description in section 6. l Photonic LO system & Calibration source¡V Yugene will input more block diagrams after discussing with NRAO persons. l IF system ¡V T.H. Chu says that he will provide the equalizer information. l Correlator ¡V Warwick says that he will write some information for the prototype. Jeff suggests that we should not put our efforts on building the prototype in module. Warwick agrees with Jeff¡¦s opinion, he says that we should not go too far for the prototype. l Computer control ¡V Michael says that he will provide some information on the computer section.	B. Martin H.C. Lu M.Kesteven M.T. Chen Y.J. Hwang T.H. Chu W. Wilson M.Kesteven	Ongoing ASAP ASAP ASAP Ongoing ASAP ASAP ASAP
Travelling
Yugene / Sep. 23 ~ Oct. 6; Bob / Oct.9 ~ Oct. 26
Next Meeting
8:30pm EDT, 8:30am Taiwan, 10:30 Australia, 5:30pm Tucson/Thursday/5. Oct. 2000