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    how to reduce the inductance of a 3 loop antenna

    Hello Guys ,

    Please have a look at the following loop(15mm length 2mm thick) antenna for 432Mhz Transmitter hand held device ,which is for PCB. I want to know about the following;



    1) What value of Variable capacitor to select (PCB is FR4 , 1.6mm thick standard).

    2) Can loop be made small if yes what dimension.


    Thank you
    -Ts

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    wonder loop antenna

    It needs full study before commenting on your questions.
    Let say,
    1)you need the tuner for a range then what is the frequency range interested?
    2) you have variable cap in series, what is the inductance of the circuit?
    3) then calculate the C range

    finally yes you can reduce the loop dimensions.



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    reducing inductance of loop antenna

    Quote Originally Posted by kspalla
    It needs full study before commenting on your questions.
    Let say,
    1)you need the tuner for a range then what is the frequency range interested?
    2) you have variable cap in series, what is the inductance of the circuit?
    3) then calculate the C range

    finally yes you can reduce the loop dimensions.
    Thanks ,

    Actually I require an antenna for 432Mhz , I place the track as hown around 15cm approx Lambda/4 . The variable cap I see was an example from RFM app note (should the capacitor be placed parallel to loop).

    I need suggestion can the loop be left ungrounded when we are furnishing Lambda/4 requirement.

    Now when I use FR4 , 1.6mm thick dielectric 4.7 what could be the best bet for tuner capacitor . I am unsure what the inductance might come out at that frequency.

    -Ts



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    Tuning loop antenna tuning help

    You previously said length is 15 mm, now 15 cm. I also wonder what's the length of a loop? So what's the loop geometry?

    P.S.: For some reaosn, the drawing wasn't visible to me. The dimensions are still unclear, but I wouldn't call it a loop, it's rather a meander. A loop is a magnetic antenna, that has an enclosed area as significant parameter. By adding a meander, you increase only the inductance but not the area. A meander may have more effect with a monopole (open end) antenna.



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    Re: Tuning loop antenna tuning help

    Quote Originally Posted by FvM
    You previously said length is 15 mm, now 15 cm. I also wonder what's the length of a loop? So what's the loop geometry?

    P.S.: For some reaosn, the drawing wasn't visible to me. The dimensions are still unclear, but I wouldn't call it a loop, it's rather a meander. A loop is a magnetic antenna, that has an enclosed area as significant parameter. By adding a meander, you increase only the inductance but not the area. A meander may have more effect with a monopole (open end) antenna.
    Apologies , that was a typo it is 15cm (Lambda/4 @ 432MHz) . I repost the schematic here ;


    'A' drawing is a meander and 'B' is I try to tune a meander . Actually the antenna is for a short range link and it has to suffer hand effect and nearby metallic box . I think as the range is not critical 10meter or so , therefore go for this type of design . I am at this point of time unable to download or study HFSS or other simulation but some time in future will definitely download it .
    I require suggestions as to what type of antena is the best , the A or B . The B has a quality of a loop as well to stay immune from coupling effects. If one goes for 'B' then what tuner capacitor is required . I couldnt get the Inductance of this type of trace at 432MHz difficult . If trimmer capacitor option is better then please advise value?

    Thanks
    -Ts



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