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good morning all,

I have difficulties to find the correct formula that allows me to calculate the gain of half wave dipole in parallel with another parasitic half wave dipole. I'm trying to calculate the gain(theta,phi) of this array for different distances bentween the two dipoles. If you have any interesting book or link that would be great.

Best regards enter image description here

$$ G_f(\phi)\left[\frac{\mathrm{A}}{\mathrm{HW}}\right] = \sqrt{\frac{R_{11}+R_{1L}}{R_{11}+R_{1L}-\lvert Z^2_{12}/Z_{22}\lvert \cos(2\tau_m-\tau_2)}} \times \left( 1+\left\lvert \frac{Z_{12}}{Z_{22}}\right\lvert \frac{\zeta+d_r\cos\phi}{} \right) $$

enter image description here enter image description here

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    $\begingroup$ Figure frome John.D KRAUS's book (Antennas for all applications, 3rd edition, P477) $\endgroup$ – Tarik L Oct 7 at 14:33
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    $\begingroup$ Does the graph illustrate the difference between the calculated results of the equations and NEC2 simulations? $\endgroup$ – Brian K1LI Oct 8 at 12:17
  • $\begingroup$ Yes sir (freq=868MHz), and i'm looking if there is another formula ! $\endgroup$ – Tarik L Oct 9 at 11:14
  • $\begingroup$ Hey Tarik, I tried to write the equation in MathJax. How did I do? I couldn't read a few of the subscripts. If I made any mistakes please let me know in the comments and I'll fix them, or edit the question if you want to fix them yourself. $\endgroup$ – rclocher3 Oct 13 at 19:48
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The demo version of EZNEC software (free) would be able to do that, with a fairly short learning curve: https://www.eznec.com/demoinfo.htm

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  • $\begingroup$ Thanks a lot sir. I already did it with EZNEC and 4NEC2, but i'm looking for the right mathematical formula. $\endgroup$ – Tarik L Oct 8 at 8:03

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