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mfarhan1
Joined: 20 Apr 2007
Posts: 227
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Location: UK
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 09 Jul 2008 15:38 Subharmonic Mixer |
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Dear all
I want to simulate an ideal (or real) subharmonic mixer in ADS. I could nt find any model for subharmonic mixer in ADS library and ADS toolbars that i can use.
The hardware component i have is XLD-X3 subharmonic mixer from synergy.
Can any one guide me how can i simulate subharmonic mixer? I dont want to design it.
Thanks, your help is really appreciated
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RF-OM
Joined: 03 Aug 2007
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| 14 Jul 2008 22:15 Re: Subharmonic Mixer |
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| May be Synergy can give you a model or S-parameter file?
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mfarhan1
Joined: 20 Apr 2007
Posts: 227
Helped: 122
Location: UK
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| 15 Jul 2008 1:52 Subharmonic Mixer |
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hmmm i could not find any s parameter file on the web site of synergy. Now i am thinking of measuring S parameter by myself and put them into ADS.
any suggestion for alternative?
thanks
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RF-OM
Joined: 03 Aug 2007
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| 15 Jul 2008 7:42 Re: Subharmonic Mixer |
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| I think you can do it. There may be a couple of problems. First of all S-parameters defined for certain impedance and all three ports must be terminated with this the same impedance. This is often not the case for mixers, moreover mixer often have different impedance during the single period of LO signal. You may try to use VNA and measure the S-parameters, but what VNA will actually measure it is hard to say. Next problem may be with different relation between input and output signals compare with normal mixers. You need to check what your particular VNA requires for mixer measurements. There are some application notes on Agilent web site about mixer measurements with VNA. If you will not find them let me know and I may check my library.
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khouly
Joined: 20 Oct 2003
Posts: 2414
Helped: 331
Location: EGYPT
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| 15 Jul 2008 7:45 Subharmonic Mixer |
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i don't know, if u inculded the S pam of the mixer ADS will take the mixing action into account or not.
u can make it by using freq multipier and mixer. this will be a system block.
khouly
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toonafishy
Joined: 18 Jun 2002
Posts: 416
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| 15 Jul 2008 7:49 Re: Subharmonic Mixer |
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| subhamonic mixing is a non linear process. i doubt S parameters will capture the performance
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khouly
Joined: 20 Oct 2003
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| 15 Jul 2008 8:21 Re: Subharmonic Mixer |
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please check the document i have attached
it is a very simple system models in ADS i have created from the frequency multiplier and mixer a subharmonic mixer
wish this helps u
khouly
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RF-OM
Joined: 03 Aug 2007
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| 16 Jul 2008 6:01 Re: Subharmonic Mixer |
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To toonafishy,
Yes, usage of S-parameters for mixer measurement and analyzes is not easy task. But it is possible. May be not for any case, but at least for some of them. By the way, I afraid that some of EDAboard members will fight to this opinion, but this is the true that linear mixer is possible. I mean mixer that made from linear (from RF point of view) elements. I invented such circuits, built them, tested and used a lot. They performed excellent, but I am sure many of university professors will bite me immediately. The beauty of these mixers is that they provide very high quality mixing and for some of them no LO currents practically flow through the mixer. These circuits may be considered as a kind of subharmonic when IF is not equal to n*RF+/-m*LO and they may be well described with standard S3P files. Therefore at least for some cases it is possible to use S-parameters file for mixer analyzes.
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khouly
Joined: 20 Oct 2003
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Helped: 331
Location: EGYPT
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| 16 Jul 2008 6:53 Subharmonic Mixer |
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RF-OM
do u mean by the linear mixer is the mixer based on time variant linear element. like the resistive FET mixer and so on. yeah this is possible , even i have designed and tested one.
if you mean other circuit would u please give a link for it or give a paper.
thanks
Khouly
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RF-OM
Joined: 03 Aug 2007
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| 16 Jul 2008 7:51 Re: Subharmonic Mixer |
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| You are right: such a mixer is one of an examples for mixer built with linear element. But in this case impedance is variable and usually we may consider it as geometric means from min and max values. At least for noise calculations. In previous post I mean another circuits. There are no links and papers because I did not publish the results due to the special purpose of these developments. It is still closed for a while. It is interesting that today you practically immediately mentioned at least one example of such a circuits. Long time ago I spent about two years until I found the mathematical prove that linear mixer is possible into one of rare and very old book that was publish in 1964.
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khouly
Joined: 20 Oct 2003
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Helped: 331
Location: EGYPT
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| 16 Jul 2008 8:24 Subharmonic Mixer |
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i worked with mixers alot during my master work , which is have finished very soon. my main reference was Steve Maas work.
khouly
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RF-OM
Joined: 03 Aug 2007
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| 16 Jul 2008 8:40 Re: Subharmonic Mixer |
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| Oh, I know Steve and his books. He is one of the best authors about mixers and noise. Good luck with your masters!
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khouly
Joined: 20 Oct 2003
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Helped: 331
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| 16 Jul 2008 9:02 Subharmonic Mixer |
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thanks RF-OM
yeah Steve Maas is great author. i studied his book about nonlinear microwave circuits it is amazing.
khouly
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RF-OM
Joined: 03 Aug 2007
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| 16 Jul 2008 9:17 Re: Subharmonic Mixer |
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| Yes, he is nice to talk too and he is definitely knows all these subjects well.
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mfarhan1
Joined: 20 Apr 2007
Posts: 227
Helped: 122
Location: UK
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| 16 Jul 2008 19:40 Re: Subharmonic Mixer |
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First of all
Thanks to all of you for your expert advice.
The file uploaded by khouly is really helpfull and very interesting way of simulating Subharmonic mixer. I agree with toonafishy and RF-OM that S paramter is not that stright as they are for filters etc, I dont want to put myself in that trouble of calculating S parameters. RF-OM i did look on agilent application notes they are really helpful when measuring mixers.
Very amazing to know about mixer with linear elements. Stev maas has written excellent books on mixers and nonlinear elements i read them. I am working on mixers with Prof. I.D Robertson and would seek your help further
By the way is any of you working on LTCC!
Cheers all.
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khouly
Joined: 20 Oct 2003
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Helped: 331
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| 16 Jul 2008 20:02 Subharmonic Mixer |
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i am trying to find information about it , and how to design microwave circuits using LTCC. but LTCC is design is always a process dependent so u need to have a design kit fot it
if u have any resorses about it please share
Khouly
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RF-OM
Joined: 03 Aug 2007
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| 16 Jul 2008 22:15 Re: Subharmonic Mixer |
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| As far as I know LTCC is make sense on frequencies higher than 10 GHz. Below 10 GHz it is too expensive and may provide too low yield. This is very old technology, but surprisingly there is almost no changes for so many years. I considered LTCC for several times and always regular PCB won.
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khouly
Joined: 20 Oct 2003
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Helped: 331
Location: EGYPT
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| 16 Jul 2008 23:26 Subharmonic Mixer |
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what about think film technology , i saw many RF FEMs and PAM's are designed using thin film
also this technology is used in RF SIP
khouly
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RF-OM
Joined: 03 Aug 2007
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| 16 Jul 2008 23:39 Re: Subharmonic Mixer |
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| I did not use this technology yet. Could you please tell a bit more about it and give some link(s) to find the information?
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khouly
Joined: 20 Oct 2003
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Helped: 331
Location: EGYPT
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| 17 Jul 2008 0:40 Subharmonic Mixer |
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check this
http://www.imec.be/wwwinter/mediacenter/en/SR2006/681438.html
http://eesof.tm.agilent.com/pdf/rf_sip_module_design_verification.pdf
http://www.thin-film.com/web/TFT.nsf/+view+/A4FB30ADCDB0C7F8862573F6007E6160/$FILE/tft_custom_electrical_filter_designs.pdf
khouly
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RF-OM
Joined: 03 Aug 2007
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| 17 Jul 2008 1:09 Re: Subharmonic Mixer |
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Thanks a lot! It is interesting and the accuracy of the geometry must be much higher that for LTCC. For SIP it may be a good choice.
RF-OM
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mfarhan1
Joined: 20 Apr 2007
Posts: 227
Helped: 122
Location: UK
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| 17 Jul 2008 10:47 Re: Subharmonic Mixer |
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yes LTCC is definitely process Dependant but it can not be compared with PCB as it gives you 3rd dimension too. It is modified version of thick film. The process is much cheaper than thin film and much faster.
The application of LTCC is not limited to circuits it has huge application in microfludics, WSN, MEMS packaging.
khouly what do you mean by design kit.
I have some good introduction literature and will share shortly.
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mfarhan1
Joined: 20 Apr 2007
Posts: 227
Helped: 122
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| 17 Jul 2008 17:31 Re: Subharmonic Mixer |
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here are two intro files on LTCC it covers the process and few applications
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RF-OM
Joined: 03 Aug 2007
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| 22 Jul 2008 18:26 Re: Subharmonic Mixer |
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Dear mfarhan1,
Unfortunately I exceed my download limit and cannot donwload your files. Could you please send them to me trough pm? Thank you in advance for your help.
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khouly
Joined: 20 Oct 2003
Posts: 2414
Helped: 331
Location: EGYPT
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| 22 Jul 2008 20:22 Subharmonic Mixer |
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very good Mfarhan1
i meant by design kit is the library provided by the foundry , which contain the models of some components ready to use
khouly
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mfarhan1
Joined: 20 Apr 2007
Posts: 227
Helped: 122
Location: UK
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| 23 Jul 2008 10:29 Subharmonic Mixer |
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@Khould
you are right it surely helps but i dont have any design kit as long as you can spare some time in momentum you can help your self with basic components,
There is no fixed topology of any component with LTCC, Like coupler can be made with single layer or with up till 4 layers it totally depends on your packaging requirements so there is no drawback not having library.
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khouly
Joined: 20 Oct 2003
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Helped: 331
Location: EGYPT
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| 23 Jul 2008 10:56 Subharmonic Mixer |
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maybe. but it will helpt get a library
even some friends of mine they generate there own library by the Advanced model composer in momentum to generate parametrized models
khouly
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