The Amp Hour Electronics Podcast

A weekly show about the trends in the electronic industry.

You are here: Home / Guest Appearance / #228 – An Interview with Shahriar from The Signal Path – Quisquous Quivering Quadripole

#228 – An Interview with Shahriar from The Signal Path – Quisquous Quivering Quadripole

Play

Podcast: Play in new window | Download

Subscribe: Apple Podcasts | RSS

 

Welcome Shahriar from The Signal Path! If you’re not already, you should definitely be subscribed to the YouTube channel.

  • 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.
    [tube]https://www.youtube.com/watch?v=9iXFhKUa1BU[/tube]
  • Chris loved Shahriar’s cryo experiments because they really showed the (extreme) effect of temperature on components.
    [tube]https://www.youtube.com/watch?v=MpCQsB1VK24[/tube]
  • 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.
    [tube]https://www.youtube.com/watch?v=dx596o8t_TY[/tube]
  • 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.

Comments

  4. The deal with IEEE copyright is actually not accurate. You are allowed to put the version of the paper on your website, just not the final one published by IEEE journal (with all the formatting etc). Putting up the preprints they send you for proofreading and offprints on your website or sharing with your students, etc is completely OK. Read the copyright release in detail – they don’t reserve all rights on it.

  5. Shahriar’s Signal Path Blog is the best out there IMO for existing EE’s, and a stellar example of a decent human being! Bless you sir.

  7. Spooks-Aerospace-Military… That’s how cutting edge technology in the US gets funded(f-ing sad).. This is the best interview ever with an engineer who really know the score! He tells it like it really is!
    This engineer is awesome! Get more like him on the show. Thanks. – retired engineer in US
    who’s been there, done that, and has the t-shirt, and worn it out.

  9. I love your show, and especially this one. What an intelligent and compassionate person Dr. Shahriar is. Keep up the great work of interviewing people who are cutting paths for a better future. Even though I’m not a PhD I do enjoy listening. I really appreciated Dr. Shahriar’s understanding of what functioning and declining societies need and look like. I was a Social Worker and am the daughter of a Holocaust survivor so I can really related to this. Thank you.

  10. Thank you Dave & Chris for the best interview yet. Thank you Shahriar for sharing the lights of knowledge. Philomathea Paradigm Power…

  12. I wonder if anyone has ever noticed that Shariar kinda looks like the guitarist from ‘The Strokes’ (Albert Hammond, Jr).

    Check out the video ‘Last Nite’ to see

Trackbacks