High Frequency Electronics and radio

Discussion in 'General Electronics Chat' started by Robin Mitchell, Nov 7, 2014.

  1. Robin Mitchell

    Thread Starter Well-Known Member

    Oct 25, 2009
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    Hi all,

    I have always wondered something...

    I want to build a radio receiving circuit and wish to detect signals in the 100MHz region but this got me thinking. How can electronic circuits pick up signals greater than so many gigahertz? What frequencies can radio circuits really function at? What are the largest frequencies that electronic circuits can operate at? Can circuits really function at frequencies greater than 10GHz?

    All the best,
    Robin Mitchell
     
  2. crutschow

    Expert

    Mar 14, 2008
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    Microwave circuits are commonly used that operate above 100 GHz, with experimental circuits operating in the THz area. Of course at those frequencies you can't use wire to conduct the signals over any significant distance so some form of waveguide is typically used.
     
  3. flat5

    Active Member

    Nov 13, 2008
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    There are oscilloscopes that can do analysis at 100Ghz.
    BTW, they are not inexpensive.
     
  4. takao21203

    Distinguished Member

    Apr 28, 2012
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    at 100 MHz a 3.5 Turns air coil has significant influence on the circuit.
    At 300 MHz, a PCB trace can be used as inductor.

    Generally, GHz circuits tend to be very small, and special structures are used on the PCBs, called microstrips.

    Above 10 GHz isnt used in consumer electronics as far as I know.

    100 MHz isnt difficult if you use Manhattan or "Dead bug" style on perfboard (with the copper side up).
    But above that, it gets more and more difficult, with 800 MHz or so being the margin what you can do with conventional circuit technology.
     
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  5. ian field

    Distinguished Member

    Oct 27, 2012
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    Just past millimetre wave radar is longwave IR.
     
  6. alfacliff

    Well-Known Member

    Dec 13, 2013
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    checkout J Chagdesh Bose ( I hope the spelling is right) he was working with milimeter waves back when marconi was working with long waves. He invented a lot of the stuff used today, waveguide, dielectric lenses, polarization shifting, p, and n type semiconductor detectors and a lot else.
     
  7. bertus

    Administrator

    Apr 5, 2008
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  8. ian field

    Distinguished Member

    Oct 27, 2012
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    In the earliest ventures into experimentation with Hertzian waves, no one had any notion of winding coils - the nearest anyone had to inductance was a hoop of metal.

    It was basically UHF and up.
     
  9. takao21203

    Distinguished Member

    Apr 28, 2012
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    Did you find this info on wikipedia? Can you cite any sources?
     
  10. bertus

    Administrator

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  11. ian field

    Distinguished Member

    Oct 27, 2012
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    Can't remember where I read that - probably an e-book or magazine article on the history of radio.
     
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