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    Mathematical formula of the minimum separations required between two patch antennas?

    Hello,
    please i want to know the D (maximum dimension of antenna) given in this equation is the width * length of the patch antenna or not?Click image for larger version. 

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    Re: Mathematical formula of the minimum separations required between two patch antenn

    Hi Suo,

    This looks like the equation for the far-field distance of an antenna; in that case D is typically taken to be the diameter of the smallest possible sphere that encloses your antenna.



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    Re: Mathematical formula of the minimum separations required between two patch antenn

    so do you know the mathematical formula between the distance between element patch antennas and dimentions of antennas?



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    Re: Mathematical formula of the minimum separations required between two patch antenn

    I have a weather forecast system (WeatherDirect) that receives information over the internet. The three units talk by rf communication. The instructions advise me not to place them close together.

    In fact they state in the event one unit doesn't recognize the other, then I should increase their separation as much as several feet. I suppose multipath is the issue here. Perhaps it is most problematic when reflective objects are close to both transmitter and receiver.



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    Re: Mathematical formula of the minimum separations required between two patch antenn

    Quote Originally Posted by Suo View Post
    i want to know the D (maximum dimension of antenna) given in this equation is the width * length of the patch antenna or not?
    In the far-field equation, D is the largest dimension of the antenna.
    In case of a patch antenna, D will be equal to which one is bigger, from L length or W width.



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    Re: Mathematical formula of the minimum separations required between two patch antenn

    Hello vfone,
    what do you mean please?
    you mean that when the length is bigger than the width of rectangular patch antenna, then D is the length and vice versa?
    i need your answer please.



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    Re: Mathematical formula of the minimum separations required between two patch antenn

    Yes, exactly.
    In patch antenna design generally the width W is larger than the length L, but there are applications (some array antennas) where is in the other way.



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    Re: Mathematical formula of the minimum separations required between two patch antenn

    What is "wavelength of lower cutoff frequency"? Cutoff frequency of array?
    Does this imply the following:
    For narrow-band antennas lambda=1 D=0.5 and dmin=2*d^2/lambda=0.5
    Then for wide-band antennas separation must be bigger. as lambda is fraction of 1?



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