Dipole Antenna Gain vs Electric Field in HFSS

[kmeht46337]

Hello,

I'm simulating a dipole antenna array in HFSS at f = 1GHz. I'd like to get the array response of the dipole antennas, so I'm capturing the theta-polarized electric field (Eth). To check my work, I'm also recording the gain of each antenna element from HFSS.

My question comes in comparing the gain and Eth. The gain plot is in dB (10log10), so I estimated that the quantity 10*log10(abs(Eth)) should be equal to the gain. It is not. A plot of the two values is shown below. There seems to be a difference of some scaling factor. Does anyone know how HFSS computes the gain values, like what equations? Is my relationship between the field and the gain correct?

Thanks!
KMeht46337

 

[MuroSamuro]

Gain is not the electric field in dB.
I suggest you look at Balanis or other textbook for Directivity which is the radiation intensity at a specific direction divided by the averaged radiation intensity.
Then you can understand the term 'antenna gain' which is very similar to the Directivity.

 

[D.A.(Tony)Stewart]

looks like near-field reflections

https://www.ahsystems.com/EMC-formulas-equations/field-intensity-calculation.php

 

[volker@muehlhaus]

I'd like to get the array response of the dipole antennas, so I'm capturing the theta-polarized electric field (Eth).

Gain is a far field parameter! It is calculated by measuring the near field data, and internally running transformation from near field to far field.
You should really use the calculated gain, not the (near) field data.