AMiBA PROJECT WEEKLY MEETING MINUTES

Date: 8 March 2001

Participants: B. Martin, H. Wang, W. Warwick, M.Sinclair, M. Kesteven, M.T. Chen, H.C. Lu, R. Wei, W. Ho, Homin Jiang, P. Shaw, Jean Cheng

Issues and Description	Action by			Output
MMIC
1. Regarding the HPF purchasing issue, Leo got the response from Quinstar. They accepted our proposal, the price for the first four units is $4,000USD, and the second order for the rest of 36 units is $4,000USD. But Leo found there are some discrepancy between their offer and our specs, offered, Loe will ask Quinstar to clarify. 2. As for purchasing the InP HEMT & HBT MMIC foundry run from TRW, we are still waiting for the NDA document; Paul will follow up and send an email to Stracy Bui. 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, Mal has sent out an email to Stracy Bui, and a copy to Bob, Mingtang and Huei. But Huei didn¡¦t receive it, so Mal will resend it to him. 4. Regarding the test data of LNA modules from Neal Erickson/ Umass, Fred has sent an email to Sandy Weinreb asking for more information. In Sandy's response, he confirms that he designed that chip at UMass with NSF support, and he believes we are free to use the design on an AMiBA wafer run at TRW. He also suggests that keep on working on the export problem, and buys a wafer run for AMiBA later year or early 2002. There are 1100 LNA's of standard size (0.73x2 mm) on a wafer, so could have a few designs on the wafer and get enough chips for AMiBA, and he would also like to get some space on the AMiBA wafer for new experimental designs. 5. Since we need the module drawing and the dimension of w-band LNA to proceed our receiver design, Huei will ask Neal Erickson to provide this information directly to him or through Jeff. Bob thinks it probably is the same as to get this information through RCUH, and since he is the contact person in RUCH, so he will email his address of Hilo office to Huei as well. 6. 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 instrument? And see what we can do. Mingtang had some idea, he will write out while he back here. 7. Eugene re-tested the Spacek's amplifier, and he got a better gain this time but still lower than the specs. T. H. told Huei that one of the amplifier leakage currency already probably due to over driving. 8. Eugene says that he is still waiting for more information of the mixer & HPF from Russian firm. Mal agrees 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. Regarding the Sub-harmonic mixer packaging, Mingtang brought back some drawings back from AT. Huei says that Todd Gaier will provide a vendor who can make the substrate. Mal says that he received a layout sketch from Eugene, and he thinks it is quite good to him. Mal will talk to Eugene further to get this packaging issue resolved. 10. After this meeting, Bob & Paul will discuss cost issue and time scale with Huei.	H.C. Lu P. Shaw W.Wilson H. Wang M.Sinclair K.Y. Lo H. Wang H. Wang B. Martin Y.J. Hwang T.H. Chu Y.J. Hwang Y.J. Hwang M. Sinclair B. Martin H. Wang			Ongoing Action item DONE DONE Action item Ongoing Ongoing Ongoing Ongoing
Lag Correlator Hybrid
1. Warwick says that Paul is doing measurement on the InP HBT multiplier, and try to measure the noise level, but hasn't get result yet. He is look at what might be involved putting the whole 16 lag correlators on the InP HBT chip. According his initial calculation, it might be able to get all along to chip 1 sq. cm. And that might take 10 wafers to produce the total quantity correlator that we want. So he will continue working on that, and trying to have a look in more detail layout, see whether that is feasible or not. Bob thinks that would be a nice and clean approach, and minimize a lot of packaging problem. 2. Regarding the 1.0 um GaAs chip, Huei says he already received the chips from TRW, he will mounted them on print circuit board and send it to AT for probing in a couple days. Huei will send a binding drawing to Warwick by email today, and he hopes get some comment back from Warwick before he send chip out. 3. Regarding the final packaging for lag correlator, Warwick plans making the multipliers and putting them together on different board, the delay line and transistors, and putting it all in one chip, so it can save packaging cost. Warwick will work out how many wafers they require to use on the current design for example. It is the next thing along with figuring out the design of correlator on chip, and estimating the cost, the time scale as well. Since for the 20GHz bandwidth, we need to do another run making another design, test and production. Bob will go over all this issue in details with Warwick on off line. As for the prototype, Warwick says that the best they can offer is a 16 GHz device, and has to put it together on the print circuit board which using the same standard techniques as they are using now. Bob says that there are a lot to do here about development, he is worry about more iteration to get design to get the last band width, and he will bring up this topic to the science group, the implication and compromise this point sustaining 16 to 20GHz band width. and what they think really works about such development. Fred says that we could not afford the whole of extra money and whole of the extra time to get the extra bandwidth, and all this issue is needed to work out by off line in the other hand. 4. Regarding how to fit the prototype measurement with two correlators instead of four, Mike will bring this issue to the science group. Michael has generated a paper for prototype test and sends it over to everyone to look. We will read this paper and discuss it by next week. 5. Regarding the 16-element correlator basis on mixer using power divider circuit, Jeff says that he had another round of back and forth design with Gramic, and they are getting close to the hard board. 6. Regarding the LNA ,Ray says that he found three firms could supply the chip in die form,they are Linear Technology, Burr Brown and Analog Device. He has contacted those firms and asked for quotation.	W.Warwick H. Wang W. Warwick W.Warwick B. Martin All J. Peterson R. Wei			Ongoing Ongoing Ongoing Next week sophieOngoing Ongoing
Receiver
1. Mingtang says he had a lot of discussion with Mal about receiver design during his visit in AT, he will summarize a report and talk to us next week. 2. Jeff will re-send a note about the little tiny window on the back of feed horn to Mingtang and Bob by fax. 3. Regarding the modeling on the circular polarization, Mal says his colleague is working on that, and he expects to get a report within a week or so. 4. Mingtang says we received two w-band LNA from NRAO, Eugene has tested them, and the result is quite identical with the data they sent to us earlier.	M.T. Chen J.Peterson M. Sinclair		ongoing ongoing Ongoing
IF/LO
1. Regarding the over-order fiber laser system, Eugene will discuss with Wawwick in detail. 2. As to purchasing the optical fiber, Eugene has figured out he need 300 m. Bob will talk with Smithsonian people to see whether they could help us to get what we need from Sumitomo. In the Mean time, Fred will talk to Kaifu and see what he can do on this issue. 3. Regarding the optical amplifier, Eugene says it is very difficult to find the required amplifier from any company, so he plans to add some gain on the LO amplifier in the individual module on the receive side and drop out the optical amplifier, and then see what effect on the LO phase noise and the performance of power level, he will discuss this issue with John as well. 4. Leo says that if they could not find the IF amplifier with 20dBM, they may combined two amplifiers together in order to get sufficient output power for correlator. Warwick recommends Leo to look at the other two companies who can provide amplifiers with more output power, and they are in MMIC chip form.		Y.J.Hwang. B. Martin K.Y. Lo Y.J.Hwang H.C. Lu T.H. Chu		Ongoing Ongoing Ongoing
Platform/Mount/Dishes
1. As for the mount, Bob says that there will be a phone meeting with Vertex tomorrow to find out what they are working on in the past week and half. The manufacturing is moving forward on the tooling for small dish. He try to assemble a final optical layout drawings by earlier next week and circulate to everyone to look. . 2. Mike has sent the specs and drawing of mount to the Sydney Engineering Co, he will talk to them in details tomorrow.		B. Martin P. Shaw M. Kesteven		Ongoing Ongoing
Computer control
Bob thinks we need to think about the computer control around the whole system of AMiBA array, we need to set up a standard. He wants to bring this issue up, let people to think about a bit, when we come back to here and decide really what is we needed. Mike mentions that he still haven¡¦t seen a detail what fulfill the needs of controlling among mount, receiver and LO. He can understand the correlator, the platform and the interface, but he hasn¡¦t seen any specification for the hardware. Bob says that we do need some sort of real time control and timing synchronization. Mike says that in the on-line specification, they have a model, which a clock distributes the regular signal, and they have a device which treat the clock, and that give us the synchronization. Mike will put some together and comment what he thinks we need for computer control. Jeff suggests we had better to keep it simple in order to save time and cost.		M. Kesteven	Action item
Test plan
Mike has generated a test plan for prototype and circulated to everyone to look, any comment on it should be sent to Mike, and copy to Bob and Paul.		All	Action item
Next Meeting
7:30pm EDT, 8:30am Taiwan, 10:30 Australia, 4:30pm Tucson/Thursday/March 15, 2001