Scale model measurements - For discussion

[hntko]

Dear all,

I am interesting in "Scale model measurements" issues. In my hand now is the Balanis's book called "Antenna - Theory analysis and design". It is a very famous book for every antenna engineer, I think. For the geometrical scale model in chapter 16 of this book (page 880 and 881), it highlighted that there are some scaled parameters and some unchanged parameters. The following is some examples:
Scaled parameters
Length
Frequency
Conductivity

Unchanged parameters
Permittivity
Impedance
Antenna gain

My question is, when we apply the geometrical scale for a printed antenna, do we need to scale the thickness of the antenna's substrate? I think “Yes” because the thickness is a length parameter, but I am not sure. I have no experience in this issue.

What is your answer? Please give some explanations. Thank you so much for your discussion.

Le

 

[Kohi_boy]

Yes.

The object being scaled should remain electrically the same dimension.

The dielectric constant should remains the same as the material used did not change. Thus when frequency is changed, the wavelength in the material also changes. The length of the material, usually of certain ratio of wavelength will also correspond accordingly.