Modern Electronic Communication by Gary Miller Chapter 14 with Answers

Chapter 14 Waveguides & RADAR

1	At a frequency of 1 Ghz and transmitter-receiver distance of 30 mi, which is the most efficient device for energy transfer?
	a. Transmission lines
	b. Waveguides
	c. Antennas
	d. None of the above
2	The most efficient means of transmitting a 1-Ghz signal 1500 ft would typically be
	a. Transmission lines
	b. Waveguides
	c. Antennas
	d. None of the above
3	The dominant mode for waveguide operation is
	a. TE10
	b. TE01
	c. TM10
	d. TM01
4	The propagation velocity of the signal in a waveguide, when compared to the speed of light is
	a. larger
	b. smaller
	c. the same velocity
	d. either b or c
5	Ridged waveguides are advantageous over rectangular waveguides in their
	a. cost
	b. attenuation
	c. ability to work at lower frequency
	d. ease of construction
6	A circular waveguide is used for
	a. Efficiency reasons
	b. Ease of manufacture
	c. Rotating section applications
	d. Greater bandwidth
7	Variable attenuators are used in waveguides to
	a. Isolate a source from reflections at its load so as to preclude frequency pulling.
	b. Adjust the signal levels.
	c. Measure signal levels.
	d. All the above.
8	The coupling in dB of a directional coupler that has 85 mW into the main guide and 0.45 mW out the secondary guide is
	a. 22.8
	b. 18.9
	c. 188.9
	d. 45.6
9	The resonant frequency of a cavity may be varied by changing the cavity's
	a. Volume
	b. Inductance
	c. Capacitance
	d. All the above
10	The guide wavelength is
	a. Greater than free-space wavelength
	b. Equal to free-space wavelength
	c. Less than free-space wavelength
	d. All the above
11	The process of employing radio waves to detect and locate physical objects is known as
	a. The Doppler effect
	b. Radar
	c. Directional coupling
	d. Cavity tuning
12	The use of two grounded conductors that sandwich a smaller conductive strip with constant separation by a dielectric material on a printed circuit board for use at frequencies above 500 Mhz is known as
	a. Artwork traces
	b. Dielectric waveguide
	c. Microstrip/stripline
	d. MICs or MMICs
13	Second return echoes are
	a. Echoes produced when the reflected beam makes a second trip
	b. Echoes that arrive after the transmission of the next pulse
	c. Echoes caused by the PRT being too long
	d. All the above
14	The characteristic wave impedance for waveguides is
	a. 75
	b. 377
	c. Dependent on frequency
	d. Dependent on waveguide shape
	e. c and d
15	A dielectric waveguide is
	a. Enclosed by a conducting material
	b. A waveguide with just a dielectric
	c. Dependent on the principle that two dissimilar dielectrics can guide waves
	d. b and c

Answers:

C

B

A

B

C

C

D

A

D

A

B

C

B

E

D