Why can a radar with circularly polarized antenna not see a conductive surface?

Thread Starter

okati

Joined Jan 8, 2022
1
We know that conductive surfaces reflect the radar signals very well and the radar sees the surface. Why this is not like that when the antenna is circularly polarized?
 

nsaspook

Joined Aug 27, 2009
9,727
https://www.rfcafe.com/references/electrical/ew-radar-handbook/polarization.htm
If the desired antenna is used for a receiving a wave with a single or odd number of reflections, such as a bistatic radar where separate antennas are used for transmit and receive as shown in Figure 6, then opposite circularly polarized antennas would be used for maximum signal reception. In this case buy antennas of opposite polarization sense (one left hand and one right hand).
 

LesJones

Joined Jan 8, 2017
3,705
I think it is probably caused by the reflected signal being the opposite circular polarisation. I.E it changes left hand to right handed circular polarisation.

Les.
 

nsaspook

Joined Aug 27, 2009
9,727
I think it is probably caused by the reflected signal being the opposite circular polarisation. I.E it changes left hand to right handed circular polarisation.

Les.
That's another reason why even number of reflection corner reflectors for radar targets are used.
1641673048261.png
1641673006267.png

Using EW decoy systems with reflectors (and other toy's) it's possible to generate returns that can fool a radar system to identity the decoy as a much larger target.
 
Last edited:
Top