cosecant square antenna intuition

[yefj]

Hello, In the link bellow they describe the idea behind cosecant square antenna radiation
I have few problems understanding the concept:
1.Why they say that h is constant?
the height of the plane is not constant the plane is descending constantly

https://www.radartutorial.eu/06.antennas/Cosecant Squared Pattern.en.html

 

[volker@muehlhaus]

the height of the plane is not constant

If you check your link, the words "constant height" are mentioned multiple times ...

“The cosecant squared pattern is a means of achieving a uniform signal strength at the input of the receiver as a target moves with a constant height within the beam.”

Vector R indicates distance to the plane, not the planes path.

 

[yefj]

Could you please make a simple ilustration of how the plane moves so i could see the constant height?(even on landing)
Thanks.

 

[FvM]

You have given the illustration, the plane is moving along the red line. Constant height trajectory is just a prerequisite of the calculation.