Looking for advice on modelling - Page 1
Forum section: electronics / projects

author: Elec_Sank
author_rank: Newbie
timestamp: June 23, 2023, 07:13:54 am
content: So, basically I'm working on a project to design a PMUT. I have to build an equivalent electrical circuit of the PMUT for which my professor told me I can use either MATLAB or LTSPICE. Any thoughts on how exactly I should proceed?Keep in mind I've only just read up on the basics of how the device works as well as it's modelling. I would love it if you could give me tips on how to get more familiar with the software as well.

author: shridmaster
author_rank: Contributor
timestamp: June 23, 2023, 07:45:19 am
content: Is this for an assignment or for research? This is something that Verilog-A is built for, SPICE would not be a great choice as it fulfills a different purpose, but you can definitely do it as long as you understand its limitations and properly understand the outputs.Either way, I don't personally have an understanding of PMUTs, I'm not familiar with MEMS physics, so I'm useless for you there, but this seems like something you need to dig into research papers about.You need to understand what the purpose of your simulation/modeling is. For example if you're only interested in the signal coming out and how to design a filter for it, you can use Python/Matlab to generate a PWL file and feed that into LTSpice. If, on the other hand, you're designing a circuit that's driving the MEMS and you need to know things like parasitic capacitance, back emf etc. that's a different process.

author: Elec_Sank
author_rank: Newbie
timestamp: June 23, 2023, 08:08:59 am
content: More like research but since I'm still an undergrad student, as you've said, I'll have to read more research papers.And I've only recently started so I've yet to figure out what the purpose of my modelling is. All I know at this point is that I have to analyse an electrical equivalent of a PMUT which is to be simulated on COMSOL and compare the results. So I'm kinda stuck at this point since I don't know where to get started on the analysis bit.I will look into Verilog-A though. Thanks for helping out!

author: moffy
author_rank: Super Contributor
timestamp: June 23, 2023, 09:54:43 am
content: Looking at some of the electrical equivalent models of a PMUT: e.g.https://dspace.mit.edu/bitstream/handle/1721.1/98507/EqCircTUFFC_Final_wNomen_Highlights.pdf?sequence=1&isAllowed=yand page 6, LTSpice would be suitable to run the simulation, the great difficulty will be coming up with the mechanical to electrical equivalence equations, that is very hard especially when you consider the number of items in the Nomenclature on pages 1-3. Can you choose a different topic?

author: Terry Bites
author_rank: Super Contributor
timestamp: June 23, 2023, 10:29:34 am
content: www.google.co.uk/search?q=Piezoelectric+Micromachined+Ultrasonic+Transducers+electrical+model+simulation&spell=1&sa=X&ved=2ahUKEwjqn_a2l9n_AhWSFMAKHbgbAzoQBSgAegQIERAB&biw=1757&bih=1001&dpr=1.88

author: Elec_Sank
author_rank: Newbie
timestamp: June 23, 2023, 12:51:21 pm
content: @Terry BitesI'm afraid I can't change my topic anymoreThank you for the article you shared though. It seems to talk extensively about the equivalent circuit model of a PMUT and I'll try going through the equations even though they do seem quite hard.Thanks a lot!

author: larsdenmark
author_rank: Regular Contributor
timestamp: June 23, 2023, 08:09:08 pm
content: What level of modelling are you looking at?Perhaps this link can helphttps://www.comsol.com/paper/simulation-of-an-aln-pmut-with-a-crossed-slit-for-enhanced-acoustic-pressure-out-82231