NAVEDTRA 14183A, NEETS Mod. 11, Ch. 1 Flashcards Preview

ATI2 MAR2017 > NAVEDTRA 14183A, NEETS Mod. 11, Ch. 1 > Flashcards

Flashcards in NAVEDTRA 14183A, NEETS Mod. 11, Ch. 1 Deck (31)
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1
Q

The microwave region is that portion of the electromagnetic spectrum which falls between 1000 megahertz and what?

A

100,000 megahertz

2
Q

What is microwave theory based on?

A

Electromagnetic fields

3
Q

Which transmission media is more efficient than two-wire lines for transferring electromagnetic energy because the fields are completely confined by the conductors?

A

Coaxial lines

4
Q

What is the most efficient way to transfer electromagnetic energy?

A

Waveguides

5
Q

What is the primary lower-frequency limitation of waveguides?

A

Physical size

6
Q

A waveguide may be considered as having upper and lower quarter-wave sections and a central section which is a solid conductor that is called what?

A

Bus bar

7
Q

In practical applications, the wide dimension of a waveguide is usually what wavelength at the operating frequency?

A

0.7

8
Q

Two conditions, known as what, must be satisfied for energy to travel through a waveguide?

A

Boundary conditions

9
Q

When a quarter-wavelength probe is inserted into a waveguide and supplied with microwave energy, it will act as what type of antenna?

A

Quarter-wave vertical

10
Q

Which type of frequency in a waveguide would cause angles of incidence and reflection to be zero degrees?

A

Cutoff frequency

11
Q

What is the forward-progress velocity of the wavefront in a waveguide called that is somewhat slower than the speed of light?

A

Group velocity

12
Q

The cutoff wavelength of a circular guide is how many times the diameter of the waveguide?

A

1.71

13
Q

What are the three devices used to inject or remove energy from waveguides?

A

Probes, loops, and slots

14
Q

Power losses are greater in what type of waveguide because the inner surfaces are not perfectly smooth?

A

Flexible

15
Q

Permanent, semi-permanent, along with what else are the three basic types of waveguide joints?

A

Rotating

16
Q

What provides good electromagnetic continuity between sections of waveguide with very little power loss?

A

Choke joint

17
Q

Which electrical action takes place that causes very rapid corrosion of the metals when two dissimilar metals, such as copper and steel, are in direct contact?

A

Electrolysis

18
Q

Which type of device provides a method of sampling energy from within a waveguide for measurement or use in another circuit?

A

Directional coupler

19
Q

What is the upper frequency limit for a conventional resonant circuit?

A

2000-3000 MHz

20
Q

What is any space completely enclosed by conducting walls that can contain oscillating electromagnetic fields and possess resonant properties?

A

Resonant cavity

21
Q

Which two variables determine the primary frequency of any resonant cavity?

A

Physical size and shape

22
Q

The resonant frequency of a cavity can be varied by changing any of three parameters: cavity volume, cavity capacitance, or what else?

A

Cavity inductance

23
Q

What is it known as when you change the frequencies of a cavity?

A

Tuning

24
Q

What are used to determine the frequency of the energy traveling in a waveguide?

A

Cavities

25
Q

What is the most simple of the commonly used waveguide junctions?

A

T-Junction

26
Q

Which two basic types are T junctions divided into?

A

E and H Type

27
Q

What are the two most commonly used hybrid junctions?

A

Magic-T and Hybrid ring

28
Q

What permits a system to use the same antenna for both transmitting and receiving?

A

Duplexer

29
Q

Which type of device is composed of material that causes it to have useful magnetic properties and, at the same time, high resistance to current flow? 


A

Ferrite

30
Q

Which two basic types of motion do electrons have?

A

Orbital and Electron spin

31
Q

Which type of ferrite device can be constructed so that it allows microwave energy to pass in one direction but blocks energy in the other direction in a waveguide? 


A

Isolator