Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Capacitor design

  1. Feb 27, 2014 #1
    Hi guys,

    I'm a new member of this forum.
    As a chemist, I don't have much knowledge of electrical engineering, and that's the reason why I'm here. Hope you guys can help me out.

    I'm going to go straight to the point. I need to build a capacitor connected to an AC generator with an AC frequency of around 2 GHz (and more). I also need a power from 800W to a few kW. What do I need in order to do so? Like electronic oscillators or stuff like that? If you need any further information, please just ask.
    Thanks in advance.
     
    Last edited by a moderator: Feb 27, 2014
  2. jcsd
  3. Feb 27, 2014 #2
    A few kW at 2Ghz is a tall order. 2GHz is no problem and a few kW is no problem but putting high frequency and that high power together is pretty tough. There isn't going to be any off-the-shelf solution for you. I don't think that high current switches exist that could achieve that speed.

    I think you're going to need a very special generator custom made for something like this. It will need lot's of poles, will have to spin very fast, and be very large.

    At 2 GHz you're going to have scattering problems. Every wire and connection will have to be scrutinized for reflections or else the power will not be effectively delivered to your capacitor. Pay special attention to the connection of your capacitor. It will have a certain impedance which must be matched to the impedance of the transmission line carrying the signal. There are methods to fix scattering problems but I'm not an expert WAMI guy (Wireless and Microwave).

    Cat 5e cable would be a good choice for the transmission line. It has a characteristic impedance of about 100 Ohms. Cat 5 won't be able to handle that much power though.

    Is there any way you could scale the power down? It would make it much more feasible. 1 Watt is more realistic. If anyone has a better idea I would be most impressed.
     
  4. Feb 27, 2014 #3
    Thanks for your reply okefenokee. Unfortunately, the minimum I can go for is around 800 W, not less than that. I don't know whether all this is feasible or not. Maybe I'm just saying nonsense, but that's what I'd need.
     
  5. Feb 27, 2014 #4
    Do not attempt this. This is an extremely unsafe project. Even folks who really know what they are doing take serious precautions.

    800W at 2GHz will literally cook you. It will reach out and boil the liquid in your eyeballs within seconds.
     
  6. Feb 27, 2014 #5
    Oh man, you just gave me a bad news. But from your reply, I kind of guess this is feasible then?
    To be honest, I don't know what would happen if I used a lower AC frequency. It should work anyway but, you know, I'd need to run some experiments before saying that.
     
    Last edited: Feb 27, 2014
  7. Feb 27, 2014 #6
    Purchase a microwave oven. They are approximately the correct power and frequency.
     
  8. Feb 27, 2014 #7

    berkeman

    User Avatar

    Staff: Mentor

    Thread closed. Dangerous activities are not discussed on the PF.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook