18WuD2x

590 reflected power • refractivity
loss caused by the mismatch because the reflected
field is usually all returned again when it
arrives back at the transmitter.
reflected-power meter A radio-frequency instrument,
connected between a source and a load,
that can measure INCIDENT POWER and RE-
FLECTED POWER.
reflected ray The ray that is reflected by the surface
of a body or region it strikes. Compare INCI-
DENT RAY and REFRACTED RAY.
reflected resistance 1. In a transformer, the effective
resistance across the primary winding when
a resistive load is connected to the secondary.
2. In a transmission line, the resistance at the input
end when a load is connected to the output end.
reflected wave 1. An electromagnetic wave reflected
by the ionosphere or by the surface of the earth.
Compare INCIDENT WAVE and REFRACTED
WAVE. Also see IONOSPHERE and IONOSPHERIC
PROPAGATION. 2. A wave that is bounced off an
obstruction, such as a building or mountain.
reflecting galvanometer A galvanometer having a
light-beam pointer.
reflecting shell See IONOSPHERE.
reflection
1. The turning back of a ray by a surface
it strikes. Examples of reflecting media are the
surface of the earth, the polished surface of a material,
and a layer of the ionosphere. Compare
REFRACTION. 2. The return of energy to the
source by the mismatched end of a transmission
line or by the end of a radiator.
reflection error In a radar, radionavigation, or radiolocation
system, an error in the reading
caused by reflections of the signal from objects
other than the intended signal source or object.
reflection factor See MISMATCH FACTOR.
reflection law When a ray strikes a smooth reflecting
surface, the angle of incidence is equal to the
angle of reflection.
Incident ray
Reflected ray
reflection law
Tangent plane
Surface
= Angle of incidence
= Angle of reflection
reflection loss 1. Loss caused by the reflection of
an electromagnetic field at a discontinuity in a
transmission line. 2. Loss that occurs when an
electromagnetic wave is reflected from a surface
or object.
reflection phase grating A device that diffuses
sound waves by diffraction effects. The acoustic
equivalent of an electromagnetic-wave DIF-
FRACTION GRATING.
reflective code See GRAY CODE.
reflectivity 1. See MISMATCH FACTOR. 2. The
degree to which a point, plane, or surface reflects
the radiation (light, for example) that strikes it.
reflectometer 1. See REFLECTED-POWER ME-
TER. 2. A type of photometer used to measure reflection.
reflector 1. A smooth, metal surface or wire screen
for reflecting radio waves. See, for example,
PARABOLIC REFLECTOR. 2. A length of wire,
rod, or tubing used in a parasitic antenna to reflect
radio waves. Compare DIRECTOR and RADI-
ATOR. 3. A polished surface for reflecting visible
light or infrared rays (i.e., a mirror). 4. See RE-
PELLER.
reflector element See REFLECTOR, 2.
reflector satellite A satellite whose skin reflects
radio waves.
reflector voltage In a reflex Klystron, the reflectorto-cathode
voltage.
reflex baffle A loudspeaker BAFFLE constructed
so that some of the sound radiated to the rear of
the diaphragm is transmitted forward (after
phase shift) to boost acoustic radiation at some
frequencies.
reflex bunching In a Klystron, electron bunching
following direct-current-field-induced reversal of
the velocity-modulated electrons. Also see RE-
FLEX KLYSTRON.
reflex circuit A radio receiver circuit in which a
single transistor is used successively for different
functions. For example, one active device can act
as a mixer and as a radio-frequency amplifier.
reflex Klystron A Klystron having only one cavity.
This cavity serves first as the buncher and then,
as the electrons are turned around and caused to
pass through again, as the catcher.
refracted ray The ray that is refracted by a body or
region through which it passes. Compare INCI-
DENT RAY and REFLECTED RAY.
refracted wave An electromagnetic wave that is refracted
by the ionosphere. Compare INCIDENT
WAVE and REFLECTED WAVE. Also see IONO-
SPHERE and IONOSPHERIC PROPAGATION.
refraction
The bending of an energy ray as it
passes through media that cause a change in the
speed of propagation. It can occur with radio
waves, infrared, visible light, ultraviolet, X rays,
gamma rays, and sound waves.
refractive index See INDEX OF REFRACTION.
refractivity The extent of the ability to refract, given
as the quantity (v 1 /v 2 ) – 1, where v 1 is the phase