Optical Properties of Radio Wave Flashcards
The different waves propagated along such multiple paths interfere at the reception
multipath
propagation
Refraction of electromagnetic waves can be expressed in terms of refractive index of the atmosphere it is passing through.
π = /ππ (n = square root of ππ)
____ defined as the modulation or redistribution of energy within a wavefront when it passes near the edge of an opaque object.
Diffraction
__________ occurs when an incident wave strikes a boundary of two media and some or all of the incident power does not enter the second material.
Electromagnetic reflection
states that every point on a given spherical wavefront can be considered as a secondary point source of electromagnetic waves from which the other secondary waves are radiated outward.
Huygenβs principle
The amount of bending or refraction that occurs at the interface of the two materials of different densities.
depends on the refractive index of the two materials.
As the wave front passes the object, the point sources of waves at the edge of the obstacle create additional spherical waves that penetrate and fill in the shadow zone.
knife-edge diffraction
In Earthβs atmosphere, ray-wavefront propagation may be altered from free-space behavior by optical effects such as ________.
refraction, reflection, diffraction and
interference.
The ratio of the reflected and incident power densities is called ________________.
reflection coefficient (Ξ)
_________ is actually the changing of direction of an electromagnetic ray as it passes obliquely from one medium into another with different velocities of propagation.
Electromagnetic refraction
______ the phenomenon that allows light or radio waves to propagate (peek) around corners.
Diffraction
_ is the angle of incidence that results in an angle of refraction of exactly 90Λ
Critical angle
The fraction of power that penetrates medium 2 is called ______.
absorption coefficient
Interference as _____.
colliding
the reflected voltage intensities is less than _________.
incident voltage field intensity
_ states that a semi-rough surface will reflect as if it were a smooth surface whenever the cosine of angle of incidence is greater than π/8d, where d is the depth of irregularity.
Rayleigh criterion
refraction becomes a form of reflection
total internal reflection
the founder of the wave theory of light.
Christian Huygens
The relationship between the angles and the indices of refraction is given by a formula known as.
Snellβs law
ππππππ½π = ππππππ½π
result from the superposition of oscillations or waves of same nature and equal frequency.
Interferences
diffraction as _____.
scattering
Surface that fall between smooth and irregular is called
semi-rough surfaces
Saying all the reflected waves remain in medium 1, the velocity of the reflected and incident waves _______.
equal
It is sometimes referred to as the bending of the radio wave path.
Refraction
refractive index can be expressed as
π = π/ππ
The portion of the total incident power that is not reflected is called _______.
power transmission coefficient
(T)
refraction can be _______.
bending
When an incident wavefront strikes an irregular surface, it is randomly scattered in many directions. Such condition is called ____.
diffused reflection
critical angle can be expressed as ___.
π½π = π¬π’π§^βπ ππ/ππ
Whereas reflection from a perfectly smooth surface is called
specular (mirrorlike) reflection
reflection can be _______.
bouncing
