EM simulators for PCB? - Page 1
Forum section: electronics / rf-microwave

author: rf-fil
author_rank: Regular Contributor
timestamp: August 25, 2017, 07:10:32 am
content: Greetings, I'm going through the fun task of optimising an RF PA, in the UHF range. I've only recently started with RF PA design, having done bunch of LNAs and other low power / 50 Ohm stuff in the past.I have been modelling the power amp PCB layout manually.. tracks as sections of microstrips, etc. Aand.. it's not accurate enough.It's really tricky to get the exact impedance match to get my RF power and efficiency.. so I need a 2.5D EM simulator. Something that can give me the PCB s-parameters that are close to the real thing. I'd like to just be able to import the Gerbers, maybe tell it manually where the inductors / capacitors are located (for these, I already have s-parameters).So, what's the word on the street re Keysight ADS vs AWR Microwave Office? Any other tools out there that I am missing?Cheers

author: hendorog
author_rank: Super Contributor
timestamp: August 25, 2017, 07:19:29 am
content: Sonnet lite can do quite a lot for free if you drop down to Net-list mode.It's not obvious which is intentional as they want to protect their full license sales.I found this which despite being old explains the concept.https://www.sonnetsoftware.com/support/downloads/publications/mpdnov99.pdf

author: rfeecs
author_rank: Frequent Contributor
timestamp: August 25, 2017, 04:53:24 pm
content: Quote from: rf-fil on August 25, 2017, 07:10:32 amFor a PA, your bigger issue is you have a non-linear design. Harmonic balance simulators, like those available in ADS and Microwave Office are ideal, provided you have good models. Both programs are about the same, though people have their individual preferences. But if you have load pull data or even if you just estimate your optimum load using the load line method, you can get pretty good results with a linear simulation, at least close enough to be tunable.With both of those programs, everything is an extra cost add-on. Harmonic balance, 2.5D EM, etc. are all options.Sonnet software is also fine for 2.5D EM. But it can't do other types of simulation.Remember if you do non-linear or harmonic balance simulation, all your models need to cover frequencies from DC out to several harmonics of your carrier frequency.

author: Pitrsek
author_rank: Regular Contributor
timestamp: August 25, 2017, 06:22:15 pm
content: For harmonic balance simulation, you might want to try Qucs Studio. Qucs Studio also supports simulation with touchstone files(that's what I use it for) and spice (with caveats) + many more. For 2D field solver I use MMTL. It has it quirks, but for usual kind of PCB transmission works usually quite well.Last time I searched for something more capable I've stumbled upon OpenEMS, but haven't tried it yet.

author: rf-fil
author_rank: Regular Contributor
timestamp: August 28, 2017, 11:57:11 pm
content: Great info, thanks all.Luckily, I don't have to do HB / nonlinear stuff or load-pull analysis because I know the target drain load impedance. It's in the device datasheet. My issue is just that PCB simulation using microstrip models is not accurate enough.Cheers

author: dcarr
author_rank: Regular Contributor
timestamp: August 31, 2017, 03:46:48 am
content: Use Sonnet Lite, it's very powerful and free.

author: MrTurk
author_rank: Newbie
timestamp: September 04, 2017, 02:26:06 pm
content: I've used both ADS and AWR. Honestly say that ADS has steep learning curve. AWR MO intuitively easy to use. Unless you do some complex 3D EM stuff, it gives accurate results. If you have an academic email address they'll send free license for 4 months. It is bundled with many sample projects and has seamless integration with EDA tools(sorry for Altium) for mixed signal design.One drawback of AWR, it has limited community support and lots of unanswered forum threads online Nexus 5 cihaz?mdan Tapatalk kullan?larak gönderildi