AMiBA PROJECT WEEKLY MEETING MINUTES

Date: 26,October 2000

Attendants: J. Peterson, H. Wang , T.H. Chu, M.T. Chen, C.H. Lu, Y.J. Hwang, C.W. Lu, 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, Mal says the target date to do that test should be in the end of this month. Huei received an insulation measurement result for the SHP mixer chip from Mal. 2. Huei says that the first design for the InP HEMT MMIC is ready, and now is waiting for the wafer test data from JPL. Todd told him that he needs two weeks more to work out that test data. Fred says he will visit Pasadena in a week time. So Huei will inform Todd about Fred visit and ask him to arrange an appointment with the person in NASA who is responsible for the export license approval. 3. As for the 0.1um GaAs HEMT, Huei says the chip is ready shipped to TRW. There are some arguments on contract terms, and need to solve 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. Wave-guide filter ¡V Huei received some experiment data from Mal by fax, Mal will provide some drawings to Huei as well, and Huei will forward those data and drawings to Prof. Wu. This would be a good reference to Prof. Wu to develop his design in parallel. (Mal is modifying the existing design of 80 GHz to 85 GHz as we need.) As for the prototype receivers, Mal suggests Mingtang to investigate if he can find the required filters in the market. 6. As per NRAO¡¦s request, we released a formal purchase order to NRAO for purchasing the 4 units of 82~106 GHz amplifiers. Mingtang will directly contact NRAO¡¦s engineer in order to get some technical data, including the layouts of amplifier. 7.Mal says that he received a reminder the wafer is back this week, the plan is to test more chips in the next couple of weeks. All the hardware of the amplifiers blocks in completed, so he expects to start to test that w-band InP LNA chips sometime by end next week. So he hopes to work out some test results in three weeks. 8.According to the contract terms, Specek should pay the delay penalty to Taida. Because of the deviation on the conversion loss with the specs is not much, and it can be compensated by other IF components. So Prof. will inform the above decision to Specek.	H. Wang M. Sinclair K.Y. Lo H.Wang H.Wang M.Sinclair H. Wang M.T. Chen H.C. Lu MT. Chen H. Wang T.H. Chu		DONE ongoing ongoing ongoing ongoing ASAP ASAP ASAP ASAP
Lag Correlator Hybrid
1. Jeff says if we could use the alumina for the transmission line in the correlator, the area required for the whole correlator would be 5 times smaller. Currently some of his students are working on this study and doing some calculation. And it needs a couple of weeks more to know the answer. 2. Regarding the prototype mixer based lag correlator, Jeff will inform the update status by next week 3. Warwick says that they have made some measurement on the HBT Gilbert Cell multiplier wafer, the result is quite similar with the simulation, and he think there is a possibility to use that multiplier up to 16 to 20GHz bandwidth. Warwick will collect more measurement data, generate a report, and send over to Huei and Jeff to take a look. 4.The ACX Company has answered Warwick¡¦s enquiry about the correlator element fabrication by email, they also raised some questions to us. Warwick right now is working on those questions. 5. Warwick says he got the low bandwidth prototype working now, got the first spectrum the other day, and it is working quite nicely at the 3 GHz bandwidth, simulate the result of Andy Harris shown. He is doing a test on it at this moment, trying to figure out what the frequency response has on the performance. And he thinks it looks quite promising to work with the 3 GHz bandwidth correlator. 6.Huei says that they finished the design work on the Gilbert Cells Multiplier, but there are some Problems unsolved. So he will talk to Paul Robert to find out solution.	J. Peterson J.Peterson W. Wilson H. Wang		ongoing next week ongoing ASAP
Receiver
1. Mingtang is working on the dewar layout; he is waiting for the mount layout. He has not decided yet the overall size, because he is still waiting for the data of some components in dewar, e.g. wave-guide. J. Kingsley is working on the mount layout; Paul will contact Jeff to know the status. Leo will speed up the components sourcing progress to collect sufficient data in order to finalize the layout design ASAP. (Paul got one layout from J. Kingsley this morning. Kingsley says that he we will send over the rest of file to Paul once he backs from Sweden (next week). 2. Regarding the collaboration proposal on the development of NRAO OMT, Mingtang thinks that is a good idea, but still needs Fred¡¦s approval. Paul asks John to provide cost breakdown and detail time schedule to us accordingly. John agrees to do so, he will work out this information together with J. Kingsley. 3. Mingtang is working on the feed horn detail design; he has worked out some calculation and circulated it to everyone last week. AT has a prototype compact corrugated feed horn; he is discussing it with Mal. 4. Jeff says he made a design for feed horn year ago, and it is very easy to machine. He will send that design data to Mingtang to look at. 5. Regarding the ¡§circular & linear fits in the system¡¨ issue, Jeff has been discussing with Michael and Bob Sault about by email back and forth, and they think a phase shifter can be used. Mingtang says he will use the simple one ¡V the linear system for prototype, and he will leave some space in deward for phase shifter if we decide to use the circular system after. Jeff, Mingtang, Michael and Bob will keep on discussing on this issue. 6. Jeff will send the window foam material information to Mingtang once he got it.	M.T.Chen H.C. Lu J. Kingsley J. Payne C.T. Mingtang M.T. Chen J.Peterson		ongoing next week ASAP ongoing ASAP ASAP
LO/IF
1.Eugene just generates a NRAO visit report today; he will circulate it to everyone to look at. We will put it on the ASIAA web site, and welcome everyone to take a look and to comment. 2.Eugene is working on ¡§the wideband LO noise effect calculation¡¨, he will send over to everyone to look at once finished. 3.Eugene will visit Japan to participate the ALMA Photonic Meeting by Nov. 7&8.		Y.J. Hwang Y.J. Hwang	DONE ASAP
Platform/Mount/Dishes
1.Jeff doesn¡¦t think the caesarian could work with the 30cm antenna due to its high ground pick up. He will do some quantitative analysis to demonstrate this case. 2.Regarding the height of ground shield for our antenna, Bob requests Michael to ask their expert to verify what size is good for us? 3.Mingtang says our new engineer assistant C.W.Lu fould a local expert in the field of Hexapod. The expert, Prof. Perng, leading a lab in the Department of Power mechanical Engineering of The Tsing-Hua University. Prof. Peng has more than 10 years research experience on Hexapod, and he is very interest in the AMiBA work. So Mingtang will invite him over to ASIAA to give a talk on what he knows and what he think about our mount. Mingtang will organize a meeting sometime during the second week of Nov.		J. Peterson M.Kesteven M.T. Chen	ASAP ongoing ongoing
Site acquisition
Bob says that he plans to visit Mauna Lao Observatory by the second week of November, to take a look on site and see what the possibility is and how we proceed.	B. Martine		Ongoing
Prototype Specification and Project Book
1. Bob and Fred asks Michael, Ravi and Bob to take a close look at some technical related science issues, e.g. UV coverage with current design on platform and drift scanning techniques, observation strategy and photonic delay line. 2. As to the secondary mirror supporting structure, Jeff will collect some material information and send it over to everyone to look at.	M.Kesteven J. Peterson		Ongoing ASAP
Visitor
Darrel Emerson Nov. 9~11 / J. Payne Nov. 9~16/ B. Martin Nov. 2~13
Traveling
Bob /Nov. 1~2,
Next Meeting
8:30pm EDT, 8:30am Taiwan, 10:30 Australia, 5:30pm Tucson/Thursday/Nov. 2. 2000