4. Propoagation Effects

Question 1

Standard vs. Anomolous Refraction

Answer 1

Standard refraction is predictable.

Anomolous refraction is not.

Question 2

What are the types of anomlous refraction?

Answer 2

Question 3

How is the radar horizon affected by refraction?

Answer 3

The effective radar horizon is increased due to refraction

Question 4

Describe Ducting/Trapping

Answer 4

Energy is trapped in a parallel plate waveguide near the surface. A duct can form due to temperature and humidity variation.

Question 5

What are shadow zones?

Answer 5

Question 6

Turbulence

Answer 6

Significatn at frequencies above 80 GHz, caused by variations in refractive index due to small fluctuations in temperautre and humidity.

Question 7

Multipath

Answer 7

When the radar wave takes multiple paths to reach the target or receiver.

Multipath can increase the range but it creates some blind spots.

Question 8

Diffuse Scattering vs Specular. How does surface roughness affect scattering.

Answer 8

Fully diffuse scattering is hemispherical.
Specular is the opposite.

A rough surface will create a more diffuse scattering effect.

Question 9

Critical Angle

Answer 9

All energy is reflected off boundary layer

Question 10

Brewster’s Angle

Answer 10

All incident energy transmitted into the boundary with no reflection