# HFSS lamda/2 dipole antenna

1. ## HFSS lamda/2 dipole antenna

Hello people!
I'm trying to create a λ/2 dipole antenna at 402MHz, but i have some questions.

Is there a rule to follow on setting : 1)the dipole radius?
2)the source rectangle?
3) the dimensions of the cylinder (of air) on which i will assign radiation?

P.S. I'm using HFSS v11!

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2. ## Re: HFSS lamda/2 dipole antenna

gap_source = lambda * 0.0125
res_length = 0.475 * lambda
dipole length = res_length/2 - (gap_source/2)

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3. ## Re: HFSS lamda/2 dipole antenna

one more:

airbox = lambda/4 (minimum)

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4. ## Re: HFSS lamda/2 dipole antenna

Originally Posted by kae_jolie
one more:

airbox = lambda/4 (minimum)
Note if you designing an antenna for 100 MHz, but are intending simulating the antenna from 80 MHz to 123 MHz, then you must use the lowest frequency (i.e. 80 MHz) in the calculation.

Another thing to watch is that for accurate simulation of the far-field, you must ensure that the maximum size of the tetrahedrals on the boundary is less than lambda_max/6, where lambda_max is the maximum frequency you simulate over. So in this case, you would need to find the wavelength at 123 MHz, and that value. I'm no expert on this, but I believe that this is more critical if you are interested in the far field radiation pattern, and is less important if you are only interested in measuring parameters at the port, such as S11.

Dave

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