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744 waveguide transformer • wave normal
waveguide transformer A waveguide component
that functions as an impedance transformer.
waveguide tuner In a waveguide system, an adjustable
tuner providing impedance transformation.
waveguide twist A length of waveguide whose
cross section is rotated around the longitudinal
axis (e.g., from vertical to horizontal).
wavelength Unit, meter. The displacement in one
complete wave of an alternating or vibrating phenomenon,
generally measured from crest to crest
or from trough to trough of successive waves. For
electromagnetic waves in free space, the wavelength
in meters is equal to 3 × 10 8 divided by the
frequency in Hertz. Also see WAVELENGTH-
PERIOD-FREQUENCY RELATIONSHIPS.
Greater
than 2λ
waveguide twist
waveguide wavelength In a uniform waveguide
operating at a given frequency and in a particular
mode, the distance between similar points for
360° phase shift.
waveguide wavemeter A waveguide component
that acts as an absorption wavemeter or transmission
wavemeter for identifying microwave
frequencies.
Movable
plunger
Voltage probe
Metal cylinder
V
waveguide wavemeter
Voltmeter
Slot for sliding
probe along guide
λ
B
A A
Wave of
energy
Energy
waveguide wedge See WEDGE, 1.
waveguide window A thin metal opening mounted
transversely inside a waveguide for impedancematching
purposes. The edges of the slit in a capacitive
window are perpendicular to the electric
field; in an inductive window, they are parallel to
the electric field.
waveguide wye In a waveguide assembly, a wyeshaped
junction for joining three waveguide sections.
wave heating Heating a material by energy absorbed
from traveling electromagnetic waves.
wave interference Interaction between two or
more waves, resulting in reinforcements and cancellations
of energy.
wavelength constant The imaginary-number
component of the propagation constant.
wavelength shifter 1. A frequency shifter whose
performance is indicated in units of wavelength,
rather than in units of frequency. 2. In certain
photosensitive cells and tubes, a photofluorescent
substance that raises the efficiency of the
device by absorbing photons and then releasing
ones of longer wavelength.
wave mechanics A theory of matter that views
subatomic particles as complex wave patterns,
and attempts to account for all physical processes
in terms of wave phenomena.
wavemeter An instrument for measuring the wavelength
or frequency of radio waves. One form consists
of a series-resonant circuit containing an
inductor, variable capacitor, and diode-type meter.
The dial of the capacitor is calibrated to read
in MHz. The inductor picks up energy from the
radio-frequency source of unknown frequency,
the capacitor is tuned for peak deflection of the
meter, and the unknown frequency is read from the
dial. This instrument is often called an absorption
wavemeter because it absorbs a certain amount of
power from the signal source under test. See also
CAVITY WAVEMETER, COAXIAL WAVEMETER,
LECHER WIRES, and SLOTTED LINE.
wave motion Undulating motion (e.g., up and
down, and side to side). An electromagnetic wave
has undulating electric and magnetic components
that are both in phase and perpendicular
to each other and to the direction of propagation
of the wave.
wave normal 1. The direction of propagation of an
electromagnetic wave. 2. A unit vector directed at