- Shahriar currently works in the ASIC design lab that is part of the Murray Hill building at Bell Labs.
- The millimeter wave researchers often say “GHz is basically DC”
- Making higher speed complex devices can be difficult but there was a 2006 paper that had a 81Gb/s timer.
- ST Micro has one of the leading SiGe BiCMOS high speed.
- The ASIC group has some of their research work fabricated at TowerJazz because it is approved by the government.
- The government has been focused on III/V semiconductor technology – InP and GaAs, GaN
- The PA/front end of cellphones/wifi uses GaAs (instead of Si) because of breakdowns of submicron processes.
- Chip designers get design kit from the fab and these are used in simulations. Here is an example of one from TSMC, provided by MOSIS (discussed previously on the show)
- Shahriar usually tests new design kits with a LNA/PA. He also designed a 160 GHZ PLL as a student.
- 3 um x 3 um capacitor is 12 fF.
- The ASIC designers use 3D EM simulation from Cadence.
- Design kits will have variations: DC characteristics like transconductance (gm) might be ok but the designers know the capacitance will have uncertainty as they characterize the design kit more.
- Dave recently did an EEVblab about what a hobbyist should know. Shahriar agrees and things knowing to test is very important.
- Chris loved Shahriar’s cryo experiments because they really showed the (extreme) effect of temperature on components.
- Testings for THz can require complex/custom test gear. Often it is a network analyzer with a front end. OML, VDI make extenders for Anritsu, Keysight.
- One Signal Path episode used a Keysight/Agilent 62GHz oscilloscope, it was on loan from the dealer.
- On scopes you start to run into the noise floor of the ADC (b/c jitter). This limits around 100 GHz. At 110GHZ the connectors become limiting (1 mm). If the connectors go to .8 mm, it could go up to 160 GHz.
- Shahriar has a range of research papers: http://scholar.google.com/citations?view_op=new_group&hl=en&nun=Shahramian&imq=author:%22Shahramian%22&authorid=2011075341937338871
- Peer review is critical for journals. Bell Labs splits research between keeping it private and publishing it.
- There are a range of technical conferences for millimeter wave research: ISCCC, SiRF, SSYCs, IMS conference
- A phased array is a grid of antennas. It allows steering the signals towards the source/receiver.
- Different high GHz bands are great because of the open bandwidth.