Waveguide

Front 1

Waveguide

Back 1

A hollow conductive tube, usually rectangular in cros section

Front 2

Waveguide

Back 2

Does not conduct current in the true sense but rather serves as a boundary that confines the EM energy

Front 3

Reflecting back and forth in zigzag manner

Back 3

EM energy propagates down a waveguide by ______

Front 4

Same order

Back 4

The cross sectional area of a waveguide must be on the _______ as the wavelength of the signal it is propagating

Front 5

Above 1GHz

Back 5

Waveguides are generally restricted to frequencies ______

Front 6

Rectangular Waveguide

Back 6

The most common form of waveguide

Front 7

Group Velocity

Back 7

The velocity at which a wave propagates

Front 8

Group velocity

Back 8

Velocity of propagation of a wave along a waveguide is less than its velocity through free space

Front 9

Group Velocity

Back 9

Actual Velocity

Front 10

Phase Velocity

Back 10

The velocity at which the wave changes phase in a direction parallel to a conducting surface

Front 11

Phase Velocity

Back 11

Apparent velocity of a particular phase of the wave

Front 12

Phase Velocity

Back 12

Determined by measuring the wavelength of a particular frequency wave

Front 13

Group Velocity

Back 13

Can be measured by determining the time it takes for a pulse to propagate a given length of waveguide

Front 14

Cutoff frequency

Back 14

Minimum frequency of operation

Front 15

Cutoff frequency

Back 15

Absolute limiting frequency; frequencies below this will not be propagated by the wavelength

Front 16

Cutoff wavelength

Back 16

Smallest free-space wavelength that is just unable to propagate in the wavelength

Front 17

Propagation Modes

Back 17

Electromagnetic waves travel down a waveguide in different configurations

Front 18

1955, Institute of Radio Engineers

Back 18

In ______, the _______ published a set of standards designated the modes for rectangular waveguides

Front 19

m and n

Back 19

Integers designating the number of half-wavelengths of intensity that exist between each pair of walls

Front 20

m

Back 20

Measured along the x axis of the waveguide

Front 21

n

Back 21

Measured along the y axis of the waveguide

Front 22

TE 1,0 mode

Back 22

Dominant mode; the most natural mode

Front 23

High pass filter

Back 23

Waveguide act as _______

Front 24

Rectangular waveguide

Back 24

Normally operated within the frequency range between fc and 2fc

Front 25

TE 10 mode

Back 25

Allows for the smallest possible size waveguide for a given frequency of operation

Front 26

Reactive Stubs

Back 26

Used in waveguides for impedance transforming and impedance matching

Front 27

Short-circuited waveguide stubs

Back 27

Used with waveguides in the same manner that they are used in transmission lines

Front 28

Inductive

Back 28

When the opening is parallel to the narrow walls, the susceptance is ______

Front 29

Capacitive

Back 29

When the opening is parallel to the wide walls, the susceptance is ______

Front 30

Wave launchers

Back 30

Couplers at the input end of a waveguide

Front 31

Wave receptors

Back 31

Couplers at the load end of the guide

Front 32

Circular waveguides

Back 32

Used in radar and microwave applications when it is necessary or advantageous to propagate both vertically and horizontally polarized waves in the same waveguide

Front 33

Circular waveguide

Back 33

Easier to manufacture and easier to join together

Have much larger area than a corresponding rectangular waveguide used to carry the same signal

The plane polarization may rotate while the wave is propagating down it

Front 34

Ridged waveguide

Back 34

More expensive to manufacture than a standard rectangular waveguide

Allows operation at lower frequencies for a given size

Smalle overall waveguide dimensions are possible

Has more power loss per unit length

Front 35

Flexible waveguide

Back 35

Consists of spiral wound ribbons of brass or copper

The outside is covered with a soft dielectric coating to keep the waveguide air and watertight

Used in microwave systems when several transmitters and receivers are interconnected to a complex combining or separating unit

Used extensively in microwave rest equipment

Front 36

Dispersion

Back 36

Limits the usefulness of waveguides with pulsed signals and other types of modulation

Front 37

Dominant mode

Back 37

Mode with the lowest cutoff frequency

Front 38

TE 11

Back 38

Dominant mode for circular guide

Front 39

Tuning screw

Back 39

A technique for matching impedance to add capacitance or inductance

Front 40

Quarter wave monopole antenna

Back 40

What does a probe resembles?

Front 41

Probe

Back 41

Couples to the electric field in the guide, and it therefore should be loacated at an electric-field maximum

Front 42

Center of the (a) dimension

Back 42

For the TE 10 mode, the prove should be at the _____

Front 43

Probe

Back 43

Launches a wave along the guide in botg directions

Front 44

Loop

Back 44

Used to couple with the magnetic field in the guide

Front 45

Directional couplers

Back 45

Used to transfer power from a waveguide to a transmission line

Front 46

Insertion loss

Back 46

The amount by which a signal in the main guide is attenuated

Front 47

Coupling specification

Back 47

Gives the amount by which the signal in the main guide is greater than that coupled to the secondary waveguide

Front 48

Directivity

Back 48

The ratio between the power coupled to the secondary guide