Log periodic antenna intuitions for its region properties

[yefj]

Hello,a log periodic antenna shown In the diagram shown bellow. As you can see there are reflective region and non radiative region. there are phase shift of 180 degrees between neighbor "wings".
I have read that the not radiative region is not radiative because it hase capcitative profile
. I can see why it has capacitate profile? And why a capacitative profile doesnt allow us to radiate?
Same this for the reflecting region,its says that its reflective because its an inductive profile. why inductive profile reflects the wave?
reflection coefficient acts as the formula shown bellow
for the wave to be reflected the LOAD has to be eigher 0 or very large impedance.
Z_L=jwL so it depends on the L and frequency value,i cant see why they say its automatic reflection of the wave?
and why its inductive profile?

Thanks.

 

[FvM]

Which textbook/paper are you referring to? Some terms related to LDPA are commonly understood like a active and inactive region, others like reflective region are not.

For a detailed explanation of LPDA, I would suggest the chapter Frequency Independent Antennas, paragraph Log-periodic Antennas in Ballanis Antenna Theory.

 

[yefj]

Hello,Can i have an intuition regarding how exactly we get a constructive sum in the main direction?
capacitative part make -90 degrees phase inductive part make +90 degrees phase so how they make 360 degrees in phase?
Thanks.