K.L.N. College of Engineering, Pottapalayam – 630 612.

(An Autonomous Institution, Affiliated to Anna University)

DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING

MCQ Practice - Question Bank

EC8701 & Antenna and Microwave Engineering

IV Year & VII semester
UNIT – I
INTRODUCTION TO MICROWAVE SYSTEMS AND ANTENNAS

Part – A ( Remember / Understand Level ) – 1 Mark Questions

1. When the separation between two lines that carry the TEM wave approaches λ the wave
tends to be
a. Reflected
b. Absorbed
c. Radiated
d. No change occurs
Answer: c
2. As the beam area of an antenna decreases, the directivity of the antenna:
a. Increases
b. Decreases
c. Remains unchanged
d. Depends on the type of the antenna
Answer: a
3. The number N of radio transmitters or point sources of radiation distributed uniformly
over the sky which an antenna can resolve is given by:
a. 4π/ ΩA
b. 2π/ ΩA
c. π/ ΩA
d. None of the mentioned
Answer: a
4. The number of point sources an antenna ideally can resolve is numerically equal to:
a) Gain of the antenna
b) Directivity
c) Beam efficiency
d) Beam area
Answer: b
 5. Gain is always ____ directivity and minimum value of directivity is ____
a. Less than , zero
b. Greater than, infinite
c. Less than, infinite
d. Greater than, zero
Answer: a
6. In a spherical coordinate system θ= 90 degree, 0<φ<360 degree refers to
a. azimuth angle
b. elevation angle
c. azimuthal plane
d. elevation plane
Answer : c
7. Effective aperture in terms of beam area and operating wavelength is given by the
relation:
a) λ2/ ΩA
b) ΩA / λ2
c) λ2× ΩA
d) No such relationship exists
Answer: a
8. ________ of an antenna is defined as the ratio of the induced voltage to the incident
electric field.
a) Effective height
b) Gain
c) Directivity
d) Loss
Answer: a
9. The directivity of an antenna in terms of the aperture efficiency and operating wavelength
is given by:
a) 4πAe/λ2
b) 2πAe/λ2
c) πAe/λ2
d) None of the mentioned
Answer: a
10. An antenna has a loss resistance of 10ohm, power gain of 20 and directivity of 22. Calculate
its radiation resistance. Given: RL=10
a) 10ohm
b) 50ohm
c) 100ohm
d) 20ohm
Answer : c
11. ____________ is a graph of the spatial variation of the electric or magnetic
field component along a constant radius.
a) retarded potential
b) retarded time
c) field pattern
d) polarization
Answer : c
12. The transmitting antenna sends __________ and receiver antenna receive ________ .
a) Spherical wave , plane wave
b) Infrared waves , plane waves
c) Radio waves , Spherical waves
d) Plane waves , Radio waves
Answer : a
13. ______________ is defined as the fractional temperature at the input of antenna which
accounts for fractional noise at output
a) effective noise temperature
b) antenna noise temperature
c) receiver nose temperature
d) noise temperature
Answer: a
14. Link margin should ranges from ___ to ____
a) 3,20
b) 4,32
c)2,30
d) 4,30
Answer: a
15. Aperture efficiency is always _________ to unity.
a) >=
b) >
c) <=
d) <
Answer : c
16. The noise temperature at the output terminals of a transmission line depends on
a. lossy line
b. impedance mismatch
c. both
d. none
Answer: c
Part – B ( Apply Level ) – 2 Mark Questions
1. If the pattern function F(θ,φ) is 20, then the radial scale of the plot of radiation pattern is
___
a. 0db
b. 10db
c. 20db
d. 26db
Answer : d

2. If D = 15 inches, λ=2.42 cm, the far field distance of the parabolic reflector is
a. 24.4876m
b. 14.487m
c. 34.4876m
d. 4.4876m
Answer: c

3. An antenna has a field pattern of E (θ) = cos2 θ, θ varies between 0 and 900. Half power beam
width of the antenna is:
a) 330
b) 660
c) 12000
d) None of the mentioned
Answer: b

4. An antenna has a field pattern E (θ) =cos θ. cos 2θ. The first null beam width of the antenna is:
a) 450
b) 900
c) 1800
d) 1200
Answer: b

5. If an antenna radiates over half a sphere, directivity of the antenna is:

a) Two
b) Four
c) Three
d) One
Answer: a

6. The half power beam width of an antenna in both θ and φ are 400 each. Then the gain of the
antenna is:
a) 23
b) 25
c) 14
d) 27
Answer: b

7. The half power beam width of an antenna in both θ and φ are 400 each. Then the gain of the
antenna is:
a) 23
b) 25
c) 14
d) 27
Answer: b

8. The directivity of a pencil beam antenna with beamwidths θ 1 = 10 degree and θ2=10 degree is
a. 224
b. 324
c. 3240
d. 2240
Answer: b

9. The Gain of an antenna is ___________ if it's directivity is 25 and efficiency is 45 .

a. 0.55
b. 1.8
c. 55
d. 11.25
Answer : d

10. If the directivity of a square corner receiving antenna is 20 and operating at a wavelength of
0.25m, the effective aperture of a square corner antenna is
a. 0.4m2
b. 0.2m2
c. 0.1m2
d. None
Answer: d

11. The radiation intensity of the major lobe of many antennas represented by U = Cos(^4) θ.
0<θ<π/2, 0<φ<2π. The beam solid angle in steradians is
a. π / 2
b. π / 5
c. 2π /5
d. 2π / 3
Answer: c
12. The power loss factor of an lossy antenna _____ , if its radiation efficiency reduced by half
a. halves
b. doubles
c. thrice
d. no change
Answer: b

13. The Figure of merit for receive antenna G/T is ____ when gain=43.97dB and noise
temperature at the antenna 93.66 Kelvin.
a. 0.4694db
b. 4.694db
c. 24.26db
d. 2.426db
Answer: c

14. The effective isotropic radiated power of the transmitter antenna with gain 20dB and carrier
power 100W is
a. 20dbm
b. 2000dbW
c. 10000dbW
d. 10000W
Answer: d

15. The equivalent noise temperature of the overall system with noise figure 2 of a system at
room temperature 300C is
a. 60K
b. 600C
c. 2900C
d. 290K
Answer: d
UNIT-2-RADIATION MECHANISMS AND DESIGN ASPECTS
PART-A

1.Types of Aperature antenna :

a) Waveguide b)Horn
c) Slot d) All the Above
Ans: All the above

2.A horn antenna depends on_________.

a)Direction b)Amount
c)Type d)All of them
Ans: All of them.

3.Condition for physical realization in horn antenna?

a)Pe=Ph
b)Pe<Ph
c)Pe+Ph
d)Pe>Ph
Ans: Pe=Ph.

4. According to the geometry, how many sterdians are present in a full sphere?
a. π/2
b. π
c. 2π
d. 4π
ANSWER: 4π
5. The vector magnetic potential shows the inverse relationship with its
a. Source
b. Distance of point from the source (R)
c. Both a and b
d. None of the above
ANSWER: Distance of point from the source (R)
6.If the length of elements of an array is greater than λ/2, which will be the operating region
of an array?
a. Transmission line region
b. Active region
c. Reflective region
d. All of the above
ANSWER: Reflective region
7.Linear polarization can be obtained only if the wave consists of
a. Ex
b. E y
c. Both Ex & E y & in phase
d. Both Ex & E y & out of phase
ANSWER: Both Ex & Ey & in phase
8. When an electromagnetic wave travels from transmitter to receiver, which factor/s affect/s
the propagation level?
a. Curvature of earth
b. Roughness of earth
c. Magnetic field of earth d. All of the above
ANSWER: All of the above
9. For avoiding ground losses, better is the surface conductivity, less is the
a. Attenuation
b. Phase velocity
c. Propagation constant
d. Tilt angle
ANSWER: Attenuation

10. On which factors of earth does the magnitude of tilt angle depend in surface wave?
A. Permittivity
B. Conductivity
C. Resistivity
D. Reflectivity
a. A & B
b. C & D
c. A & C
d. B & D
ANSWER: A & B
11.What is the direction of varying orientation of polarized surface wave at the earth surface
in a wave tilt mechanism?
a. Horizontal
b. Vertical
c. Diagonal
d. Opposite
ANSWER: Vertical
12. Which layer has the atmospheric conditions exactly opposite to that of standard
atmosphere?
a. Depression layer
b. Regression layer
c. Inversion layer
d. Invasion layer
ANSWER: Inversion layer
13.Under which conditions of two unit vectors, the polarization loss factor (PLF) is equal to
unity?
a. Perpendicular
b. Perfectly aligned
c. Angle inclination (Ψp)
d. All of the above
14.Which property/ies of antenna is/are likely to be evidenced in accordance to Reciprocity
theorem?
a. Equality of impedances
b. Equality of directional patterns
c. Equality of effective lengths
d. All of the above
ANSWER: All of the above

15. In solution evaluation process of inhomogeneous vector potential wave equation, if points
are completely removed from the source, then by which factor does the time varying field &
static solution differ?
a. e-jkr
b. ejkr
c. e-jk/r
d. e(jk + r)
ANSWER: e-jkr
18.In an electrically large loop, an overall length of the loop is equal to
a. λ/2
b. λ
c. λ/10
d. λ/50
ANSWER: λ

19.In broadside array, all the elements in the array should have similar excitation along with
similar amplitude excitation for maximum radiation.
a. Phase
b. Frequency
c. Current
d. Voltage
ANSWER: Phase
20.Which among the following is regarded as a condition of an ordinary endfire array?
a. α < βd
b. α > βd
c. α = ±βd
d. α ≠ ±βd
ANSWER: α = ±βd
21.In the solutions of inhomogeneous vector potential wave equation, which component
exists if the source is at origin and the points are removed
from the source (Jz = 0)?
a. Inward
b. Outward
c. Both a and b
d. None of the above
ANSWER: Outward
22.What is the far-field position of an electric short dipole?
a. Along x-axis
b. Along y-axis
c. Along z-axis
d. Along xy plane
ANSWER: Along z-axis
23. What would happen if the rms value of induced emf in loop acquires an angle θ = 90°?
a. Wave is incident in direction of plane of the loop with induced maximum voltage
b. Wave is incident normal to plane of the loop with no induced voltage
c. Wave is incident in opposite direction of plane of the loop with minimum voltage
d. None of the above
ANSWER: Wave is incident normal to plane of the loop with no induced voltage
24.Which of the following statement is true for bandwidth of an antenna?
(A) Inversely proportional to 1 / Q2
(B) Directly proportional to Q2
(C) Directly proportional to Q
(D) Inversely proportional to Q
ANSWER: Inversely proportional to Q
25.The polygonal loop antennas are the _________,_________,_________ and _______.
a. square, circular, triangular, and rhombic
b. square, rectangular, triangular, and rhombic
c. spherical, rectangular, triangular, and rhombic
d. square, rectangular, triangular, and cuboid
ANS: b. square, rectangular, triangular, and rhombic
26.Which antenna radiating region/s has/have independent nature of angular field distribution
over the distance from the antenna?
a. Reactive near-field region
b. Fresnel region
c. Fraunhofer region
d. All of the above
ANSWER: Fraunhofer region
27.Which antennas are renowned as patch antennas especially adopted for space craft
applications?
a. Aperture
b. Microstrip
c. Array
d. Lens
ANSWER: Microstrip
28.Which among the following plays a primary role in generation of conduction current in an
ionosphere due to presence of electric field?
a. Ions
b. Motion of electrons
c. Neutral molecules
d. None of the above
ANSWER: Motion of electrons
29.According to Snell’s law in optics, if a ray travels from dense media to rarer media, what
would be its direction w.r.t the normal?
a. Towards
b. Away
c. Across
d. Beside
ANSWER: Away
30.Which mechanism/s is/are likely to occur in mid-frequency operation corresponding to
ionospheric region?
a. Only Reflection
b. Only Refraction
c. Partial reflection & refraction
d. None of the above
ANSWER: Partial reflection & refraction
31.Which type of ground wave travels over the earth surface by acquiring direct path through
air from transmitting to receiving antennas?
a. Surface wave
b. Space wave
c. Both a & b
d. None of the above
ANSWER: Space wave
32. After which phenomenon/phenomena do the waves arrive at the receiving antenna in
ionospheric propagation?
a. Reflection or Scattering
b. Refraction
c. Defraction
d. All of the above
ANSWER: Reflection or Scattering
33.In ungrounded antennas, if an excitation is applied directly across the base insulator, then
on which factor/s would the voltage across the
insulator depend?
a. Power delivered to antenna
b. Power factor of impedance
c. Both a and b
d. None of the above
ANSWER: Both a and b
34. Which among the following exhibits perpendicular nature in TEM wave? a. Electric field
b. Magnetic field
c. Direction of propagation
d. All of the above
ANSWER: All of the above
35.Which mode of radiation occurs in an helical antenna due to smaller dimensions of helix
as compared to a wavelength?
a. Normal
b. Axial
c. Both a and b
d. None of the above
ANSWER: Normal
36.Which among the following elucidate the generation of electromagnetic waves?
A. Ampere’s law
B. Faraday’s law
C. Gauss’s law
D. Kirchhoff’s law
a. A & B
b. B & C
c. A & C
d. B & D
ANSWER: A & B
37.What is the functioning role of an antenna in receiving mode?
a. Radiator
b. Converter
c. Sensor
d. Inverter
ANSWER: Sensor
38.In lens antenna, what kind of wave energy is transformed into plane waves?
a. Convergent
b. Divergent
c. Contingent
d. Congruent
ANSWER: Divergent
39.How is the effect of selective fading reduced?
A. By high carrier reception
B. By low carrier reception
C. By single side band system
D. By double side band system
a. A & C
b. B & D
c. A & D
d. B & C
ANSWER: A & C
40.If the maximum electron density for F-layer in ionosphere is 4 x 106 electrons/cm3, then
what will be the critical frequency of EM wave for F-layer?
a. 4 MHz b. 9 MHz c. 18 MHz d. 25 MHz
ANSWER: 18 MHz
PART-B
1. In horn antenna ,directivity D= ____________?
a) 0.75*A/lamda^2 b) 7.5*A^2/lamda
c)7.5*A/lamda d)7.5A*/lamda^2
Ans:7.5A*/lamda^2

2.If the path difference of two waves with single source traveling by different pathsto
arrive at the same point, is λ/2, what would be the phase difference between them?
a. β x (λ/2)
b. β / (λ/2)
c. β + (λ/2)
d. β – (λ/2)
ANSWER: β x (λ/2)

3. The operational frequency range of a Waveguide is around _________.

a)30 MHz to300GHz b)300 MHz to 30 GHz
c)300MHz to 300GHz d) None of these.
Ans:300MHz to 300GHz

4.If a linear uniform array consists of 9 isotropic elements separated by λ/4, whatwould
be the directivity of a broadside array in dB?
a. 6.53 dB
b. 7.99 dB
c. 8.55 dB
d. 9.02 dB
ANSWER: 6.53 dB

5. According to depth of penetration, what is the percentage proportion of attenuated

wave w.r.t its original value?
a. 17%
b. 27%
c. 37%
d. 57%
ANSWER: 37%
6. If a half-wave dipole operates at 300 MHz with λ = 0.5m & D0 = 1.643, what will be its
effective area?
a. 0.032 m2
b. 0.047 m2
c. 0.65 m2
d. 0.99 m2
ANSWER: 0.032 m2

7. Which term is regarded as an inductive field as it is predictable from Biot Savart law &
considered to be of prime importance at near field or the distance close to current element?
a. 1/ r
b. 1/ r2
c. 1/ r3
d. 1/ r4
ANSWER: 1/ r2

8.If the radius of loop is λ/ 20 in a free space medium,what will be the radiation resistance of
8-turn small circular loop?
a. 0.7883 Ω
b. 50.45 Ω
c. 123.17 Ω
d. 190.01 Ω
ANSWER: 123.17 Ω
9.According to depth of penetration, what is the percentage proportion of attenuated wave
w.r.t its original value?
a. 17%
b. 27%
c. 37%
d. 57%
ANSWER: 37%
10.If the maximum electron density for F-layer in ionosphere is 4 x 106 electrons/cm3, then
what will be the critical frequency of EM wave for F-layer?
a. 4 MHz b. 9 MHz c. 18 MHz d. 25 MHz
ANSWER: 18 MHz
11.If an antenna draws 12 A current and radiates 4 kW, then what will be its radiation
resistance?
a. 22.22 ohm
b. 27.77 ohm
c. 33.33 ohm
d. 39.77 ohm
ANSWER: 27.77 ohm
11.A dipole carries r.m.s. current of about 300A across the radiation resistance 2 Ω. What
would be the power radiated by an antenna?
a. 90 kW
b. 135 kW
c. 180 kW
d. 200 kW
ANSWER: 180 kW
12.A rectangular horn antenna operating at 4GHz has the wavelength of 0.075m and gain of
about 13dBi. What will be its required capture area?
a. 0.0149 m2
b. 0.0475 m2
c. 0.5521 m2
d. 0.9732 m2
ANSWER: 0.0149 m2

13.If a half-wave dipole operates at 300 MHz with λ = 0.5m & D0 = 1.643, what will be its
effective area?
a. 0.032 m2
b. 0.047 m2
c. 0.65 m2
d. 0.99 m2
ANSWER: 0.032 m2
14.If the radius of loop is λ/ 20 in a free space medium, what will be the radiation resistance
of 8-turn small circular loop?
a. 0.7883 Ω
b. 50.45 Ω
c. 123.17 Ω
d. 190.01 Ω
ANSWER: 123.17 Ω
15.If a linear uniform array consists of 9 isotropic elements separated by λ/4, what would be
the directivity of a broadside array in dB?
a. 6.53 dB
b. 7.99 dB
c. 8.55 dB
d. 9.02 dB
ANSWER: 6.53 dB
16. Let the directivity of a microwave antenna be 900. The maximum effective aperture will
be
(A) 716.19 λ 2
(B) 71.619 λ 2
(C) 7.1619 λ 2
(D) 71619 λ 2
ANSWER: 71.619 λ 2
17.In half wave dipole antenna the radiation resistance about __________
a.26 ohm
b.52 ohm
c.73 ohm
d.70 ohm
ANS : c. 73 ohm
18.maximum effective apeture to
a.Aem = [( λ^2 /4𝜋 ) D0 ] = 3λ^2/ 5 𝜋
b.Aem = [( λ^2 /4𝜋 ) D0 ] = 3λ^2/ 7 𝜋
c.Aem = [( λ^2 /4𝜋 ) D0 ] = 3λ^2/ 8 𝜋
d.Aem = [( λ^2 /4𝜋 ) D0 ] = 7λ^2/ 8 𝜋
Ans:c. Aem = [( λ^2 /4𝜋 ) D0 ] = 3λ^2/ 8 𝜋
19. total input impedance for l = λ∕2 is equal to
a. Zin = 73 + j42.5
b.zin=26+j2.26
c.zin =42+j73.19
d.zin=11+j26.19
ANS:a. Zin = 73 + j42.5
20.The surfaces exist in ______ and___, with electric conductivities on the order of
_________
a.nature ,metals,10^7 to 10^8
b.nature,non-metals,10^6 to 10^9
c.nature ,non metals10^7 to 10^8
d.nature,metals,10^6 to 10^9
ANS: a.nature ,metals,10^7 to 10^8
21.The radiation resistance of the ferrite loop is given by
a. Rf = (𝜇ce/ 𝜇0 ).Rr
b. Rf /Rr = (𝜇ce/ 2𝜇0 )^2
c. Rf /Rr = (𝜇ce/ 𝜇0 )^2
d. Rf /Rr = (𝜇ce/ 𝜇0 )^4
ANS:c. Rf /Rr = (𝜇ce/ 𝜇0 )^2
 UNIT - 3 ANTENNA ARRAY AND APPLICATIONS
PART-A

1)Antenna arrays is used to radiate more in desired direction with _________

a) low gain
b) medium gain
c) high gain
d) moderate gain
Answer: C
2) Antenna array is used to get ________directivity in a desired direction
a) Lower
b) Greater
c) Moderate
d) Relative
Answer:B
3)________are the multi-elemented arrays that provide high directivity gain without even
feeding each element of the array
a) Collinear antenna array
b) Broadside
c) Parasitic
d) End-fire
Answer: C
4) Collinear antenna array arrangements offers maximum gain when the elements are
spaced
at a distance of about
a) 0.2 to 0.3lambda
b) 2 to 4lambda
c) 0.3 to 0.5lambda
d) 5lambda
Answer:C
5)An antenna configuration formed by arranging the elements in a straight line at a equal
distance from each other is referred as a
a) Broadcasting
b) Linear antenna
c) Point to point
d) Uniform
Answer:B
6)All the elements are excited with the current of same maginitude having a consistency
growing phase shift along the line then it is known as______
a) Directivity
b) Uniform linear array
c) Non uniform linear array
 d) Antenna array
Answer: B
7)Multi-element array uses a half wave dipole antenna .however the length is not actually
an electrical half wavelength as there is around ____ variation in the length
a) 5%
b) 8%
c) 3%
d) 4%
Answer: A
8)Working of antenna array is to be noted that the interference within the system can be
either
a) Constructive
b) Destructive
c) Both a & b
d) None of these
Answer: C
9)_______is defined as a radiating element formed by arranging various individual
antennas in a properly spaced and phased manner
a) Antenna array
b) Uniform linear array
c) Non uniform linear array
d) Directivity
Answer: A
10)Antenna array is due to providing concentrated energy in ________ suits point to point
communication
a) One direction
b) Two direction
c) Both a & b
d) Multi direction
Answer: A
11.Maximum amplitude of individual source may be________
a) Equal
b) Unequal
c) minimum
d) Maximum
Correct answer: b)
12.The field pattern of an array of nonisotropic but similar point sources is the
product of the pattern of the _________ and the pattern of an array of ________
having the same locations.
a) Individual source,isotropic point source
b) Isotropic point source,individual source
c) Individual source,individual pattern
d) Isotropic point source,isotropic element
Correct answer:a
13.The principle of pattern multiplication can be applied __________ to find the
patterns of arrays of arrays of arrays.
a) n+1 times
b) N-1 times
c) N times
d) N^2 times
Correct answer: c
14.The total normalized pattern is _______
a) E=sin pi(sqrt (1+a cos psi)^2+a^2 sin^2 psi)
b) E=cos pi(sqrt (1+a cos psi)^2+a^2 sin^2 psi)
c) E=sin pi(sqrt (1+a cos psi)^2+a^2 cos^2 psi)
d) E=cos pi(sqrt (1+a cos psi)^2+a^2 cos^2 psi)
Correct answer: a
15.The total field is __________
a)E =fp(θ , φ) + Fp(θ , φ) /f (θ , φ)F (θ , φ)
b)E = f (θ , φ)F (θ , φ) /fp(θ , φ) + Fp(θ , φ)
c)E = f (θ , φ)F (θ , φ) /fp(θ , φ) - Fp(θ , φ)
d)E =fp(θ , φ) - Fp(θ , φ) /f (θ , φ)F (θ , φ)
Correct answer: b
16.In _______ by processing the signals from the individual elements, an array
can become active and react intelligently to its environment.
a) Horn antenna
b) Helical antenna
c) Smart antenna
d) Long wire antenna
Correct answer: c) Smart antenna
17.In smart antenna interfering signal and thereby______ signal-to-noise
ratio of the desired signal.
a) Minimizing
b) Controlling
c) Equal
d) Maximizing
Correct answer: d)Maximizing
18.The phase detector compares the ____ of the downshifted signal with the ____ of
the reference oscillator
a) phase,angle
b) Angle,angle
c) Angle,phase
d) Phase,phase
Correct answer:d)
19. In smart antenna, interfering signal at 150◦ would be at a pattern______
a) Minimum
b) Maximum
c) Zero
 d) Equal
Correct answer:b)
20.Application of smart antennas are
a) Tracking in RADAR
b) Radio Astronomy
c) Radio Telescopes
d) All of the above
Correct answer: d)
21.Multiple beams may be simultaneously directed toward many signals arriving from
different directions within the field of view of the antenna. These antennas are sometimes
called ______________
a) Digital beam-forming antennas
b) Analog beam-forming antennas
c) Discrete beam-forming antennas
d) Multiple beam-forming antennas
Correct answer: a)
22.By suitable signal processing, performance may be further enhanced, giving simulated
patterns of _____ resolution and ____ side lobes.
a) higher,higher
b) Higher,lower
c) Lower,higher
d) Lower,lower
Correct answer: b)
23.For a given side lobe level the array produces the smallest beam width between the first
nulls.
A) Dolph-Tschebyscheff
B) Binomial array
C) Uniform amplitude array
D) None
Answer A)
24.Which of these distributions yields a smallest half power beam width
A) Tschebyscheff
B) Binomial array
C) Uniform amplitude array
D) None
Answer C
Uniform amplitude array < Tschebyscheff < Binomial array
25.Which of these distributions have smallest side lobes
A)Tschebyscheff
B) Binomial array
C)Uniform amplitude array
D) None
Answer B
Binomial array < Tschebyscheff < Uniform amplitude array
26.Binomial array with element spacing equal to or less than λ/2 have side lobes
A) 1
B) 0
C) 2
D) 3
Answer B no side lobes
27.When compared with uniform array super directive antennas have directivity
A) Lower
B) Higher
C) Equal
D) None
Answer B)
28.For any nonuniform array method, one of the requirements is the amplitude excitation
coefficients for a given number of elements which can be obtained by
A) (2+x)m-1
B) (1+x)m+1
C) (1-x)m-1
D) (1+x)m-1
Answer D)
29.In case of a binomial array the half power beam width when the spacing between the
elements of the arrays (d) is λ/2 is
A) 1.06/√(N-1)
B) 1.06/√(2N-1)
C) 0.75/√(2N-1)
D) 0.75/√(N-1)
Answer A) 1.06/√(N-1) or 0.75/√(L/λ) or 1.06/√(2L/λ)
30.Directivity of the binomial array method is given by
A) 1.25√N
B) 1.77√N
C) 1.06√N
D) 1.06N
Answer C)
31.Number of minor lobes of the array elements with the spacing of λ/2 and λ/4 is
A) 0
B) 1
C) 2
D) 10
Answer A) there will be no minor lobes when the array elements have spacing of about λ/2
and λ/4
32.For a 10-element binomial array with the spacing of λ/2 between the elements is
A)0.227
B)0.488
C)0.353
D)0.776
 Answer C) N=10 HPBW= 1.06/√(N-1) = 0.353 radian = 20.23 degree
33.A Dolph-Tschebyscheff array with no side lobe is reduced to
A) Dolph-Tschebyscheff
B) Binomial array
C) Uniform array
D) Linear array
Answer B)
34.The order of the Tschebyscheff polynomial is always the total number of elements.
A) One less than
B) Greater than
C) Equal to
Answer A)
35.The directivity of a Dolph-Tschebyscheff array, with a given side lobe level, increases as
the
increases.
A) Array size
B) Either Array size or number of elements
C) Number of elements
D) Both
Answer B) array size or number of elements
36.For large Dolph-Tschebyscheff array,the side lobes will be in the range of
A) -20 to 40 db
B) -20 to -60 db
C) -40 to -60db
D) 20 to 60 db
Answer B)
37.The relations between the cosine functions and the Tschebyscheff polynomials are valid
only in the range.
A) −1 ≤ z ≤ +1
B) 0 ≤ z ≤ +1
C) -1≤ z ≤ 0
Answer A)
38.Find the odd one out in the types of antenna arrays
a)broadside array b)binomial array c)parasitic array d)end fire array
ans : b) binomial array
39.example of parasitic array is
a)yagi-uda antenna b)linear antenna c)endfire antenna d)broadside antenna
ans : a)yagi-uda antenna
40.In broadside array the phase difference is
a)180 b)90 c)60 d)0
ans: d)0
41.The array used for array tapering is
a)phased array b)parasitic array c)linear array d)binomial array
ans:d)binomial array
42.Which of the following is not a types of phased array
a)dolp tchebycheff array b)frequency scanning array c)retro array d)adaptive array
ans: a)dolp tchebychevv array
43.The individual antennas of the array are equaiiy spaced along a straight line then the array
is
a)linear b)binomial c)collinear d)uniform linear
ans: a)linear
44.what kind of beamwidth is produced by chebysev arrays for given side lobe level
a)narrowest a)widest c)both a & b d) none of the above
ans : a)narrowest
45.half power beam width of broadside array is
a)57.3(lamda /L ) B)57.3(L/lamda) c)57.3(2L/ lamda) d)57.3(2lamda / L)
ans: b
46. directivity of broadside array in terms of length is
a)2L/λ b)L/λ c) λ/L d)2λ/L
ans : a
47.directivity of end fire array is
a)4 λ /nd b)nd/λ c) 4nd /λ d)λ /nd
ans :c
48.Radiation pattern of broadside array is
a)unidirectional b)bidirectional c) both a & b d)none of the above
ans : b
49.array factor =
a)Et / 2E0 B)E0 /2Et c)E0 /Et d)Et/E0
ans :a
50.directivity is
a)Uavg /Umax b)UmaxUavg c)UmaxUavg/Umax d)Umax/Uavg
ans :d
51.the mode with lowest cutoff frequency is called _ mode
a)reversing b)dominant c)practice d)least
ans :b
52.The condition of an ordinary end fire array is
a) α<βd b)α > βd c)α=±βd d)α≠±βd
53.if the elements of binomial array are separated by λ/4 how many shape patterns are
generated with no minor lobes
a)2 b)4 c) 8 d) 16
ans: c
54.which statement regarding endfire array is not correct
a)no radiation at right angles to plane of array b)dipole spacing of λ/2 c)it called linear
resonant dipole array d) narrow bandwidth
ans:b
55.if all the elements are excited with current of same magnitude having a consistently
growing phase shift along the line then the array is
a) linear b)binomial c)phased d)uniform linear
ans : d
56.if the elements are fed with equal magnitude then the array is
a)binomial b)collinear c)linear d)adaptive
ans : c
57.elements are fed with unequal amplitude then the array is
a)binomial b)collinear c)linear d)adaptive
ans : a
58.phased arrays also called as
a)linear b)binomial c)scanning d)retro
ans : c
59. which antenna array elements that change their antenna pattern dynamically to adjust to
noise interference in channel that effects on signal of interest
a)scanning b)binomial c)collinear d)smart
ans : d
60.pattern multiplication is the multiplication of single array radiation pattern with
a)beamwidth b)array factor c) total field d)directivity
ans : b
61.Multiplying the normalized field with the normalized array factor gives the
a)patterm multiplication b)array factor c)beamwidth d)none
ans : a
62. In broadside array, all the elements in the array should have similar _______excitation
along with similar amplitude excitation for maximum radiation.
a) Phase b. Frequency c. Current d. voltage
Ans: a

PART-B
1.A uniform linear array contains 10 isotropic radiation with an inter element spacing of
lamda / 4. Find directivity of broadside form of arrays
a)4 b)2 c) 7 d)5
ans : d)5
2.A linear broadband array consists of four equal isotropic inphase point sources with lamda
/3 spacing. Find the directivity
a)2 b)3 c)2.6 d)3.6
ans : c)2.6
3. A linear broadband array consists of four equal isotropic inphase point sources with lamda
/3 spacing. Find the beamwidth
a)57 deg b)57.5 deg c)59 deg d)60 deg
ans :b )57.5 deg
4.A uniform linear array contains 50 isotropic radiation with an inter element spacing of
lamda /2 . find the directivity of broadside form of arrays
a)65 b)50 c)60 d)65
ans : b)50
 5.To find the array factor for the given magnitude field is 80 and the maximum magnitude
field is 2000
a)0.4
b)0.2
c)0.6
d)0.8
Correct answer: b)
6.For a 10-element binomial array with the spacing of λ/2 between the elements is
A)0.227
B)0.488
C)0.353
D)0.776
Answer C
7. A uniform linear array consists of 16 isotropic point sources with a spacing of λ/4. If the phase
difference is 90°, calculate the directivity, HPBW, beam solid angle and effective aperture.
A) 15
B)20
C)60
D) 32
Answer A
8. A uniform linear array consists of 16 isotropic point sources with a spacing of λ/4. If the
phase difference is 90°, calculate the HPBW.
A)67
B)69
C)42
D)43
Answer:42
9. A uniform linear array consists of 16 isotropic point sources with a spacing of λ/4. If the phase
difference is 90°, calculate the beam solid angle .
A)0.89
B)0.84
C)0.87
D)0.88
Answer B

10. A broadside array operating at 100 cm wavelength consists of four half wave dipoles spaced
50 cm. Each element carries radio frequency current in the same phase and of magnitude 0.5
amperes. Calculate radiated power
A) 67
B)56
C)89
D)73
Answer: D
 K.L.N. College of Engineering, Pottapalayam – 630 612.
(An Autonomous Institution, Affiliated to Anna University)

DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING

MCQ Practice - Question Bank

EC8701 & Antenna and Microwave Engineering

IV Year & VII semester
UNIT – IV
PASSIVE AND ACTIVE MICROWAVE DEVICES
Part – A ( Remember / Understand Level ) – 1 Mark Questions

1. In Microwave frequency range ____-band ____ used for Education purpose.

L 1-2GHz,
S, 2-4GHz
X, 8-12GHz
Ku, 12-18GHz
Answer: X, 8-12GHz

2. Microwave frequency range is _____.

a. 1GHz-300GHz
b. 10KHz-30KHz
c. 100MHz-300MHz
d. 1Hz-300Hz
Answer: a. 1GHz-300GHz
3. In a phased array, beams are formed by shifting the phase of the signal emitted from
each radiating element. Name the components that solve the purpose.
a. Phase Shifter
b. Directional Coupler
c. Mixer
d. Power Divider
Answer: a. Phase Shifter

4. Analysis of Microwave frequencies can be done only by _______.

a. Hybrid (h) parameters
b. Scattering (S) Parameters
c. Admittance(Y)Parameters
d. Impedance (Z) Parameters
Answer: b. Scattering (S) Parameters

5. If the frequencies are in the microwave range , H, Y and Z parameters cannot be

measured for the following reasons:
 a. Equipment is not readily available to measure total voltage and current at the
ports of the network
b. Short and Open circuits are difficult to achieve over a broad band of
frequencies
c. Active devices, like power transistors and tunnel diodes, will not have stability
for a short or open circuit.
d. All the above
Answer: d. All the above

6. Directional Coupler is ___ port ___device used for _____.

a. 4, Passive, Coupling
b. 3, Passive, Isolation
c. 4, Active, Coupling
d. 3, Passive , Isolation
Answer: a. 4, Passive, Coupling

7. Directivity is defined as the ratio of____.

a. Backward power to the Forward Power
b. Forward power to the backward power
c. Incident Power to Back Power
d. Back Power to Incident Power
Answer: b. Forward power to the backward power
8. Coupling factor is the ratio of _____.
Incident power to the forward power
Incident power to the backward power
Forward power to the backward power
Forward power to the backward power
Answer: Incident power to the forward power

9. In a Directional Coupler, when all ports are in matched condition

a. S11≠S22 ;S33≠ S44
b. S11≠S12 ;S13≠ S14
c. S11=S22 =S33= S44=0
d. None
Answer: c. S11=S22 =S33= S44=0

10. Gunn diode exhibits_____, generates RF power directly from DC source.

a. Positive differential Resistance
b. Negative differential resistance
c. Both
d. None
Answer: Negative differential resistance
11. In the following list which one is not a Microwave coaxial connector?
a. APC3.5
b. BNC
c. SMA
d. 802.11
Answer: d. 802.11
12. ______are used for Power dividing and combining.
a. Circulators
b. Attenuators
c. Directional Couplers
d. Resonators
Answer: c. Directional Couplers
13. In order to have minimize reflections from the discontinuities, it is desirable to have
the mean length L between discontinuities equal to_______.
𝜆𝑔
a. 𝐿 = (2𝑛 + 1) 4
𝜆𝑔
b. 𝐿 = (2𝑛) 4
𝜆𝑔
c. 𝐿 = (2𝑛 + 1) 2
d. 𝐿 = (2𝑛 + 1)𝜆𝑔
𝝀𝒈
Answer: 𝑎. 𝑳 = (𝟐𝒏 + 𝟏) 𝟒

14. The basic frequency conversions of Schotkky Barrier is ____.

a. Rectification
b. Detection
c. Frequency shifting
d. All the above
Answer: d. All the above
15. The klystron tube used in a klystron amplifier is a _________ type beam amplifier.
a. Crossed field
b. Parallel field
c. Linear beam
d. None
Answer: c. Linear beam
16. In case of TWT, Microwave circuit is _____________
a. Resonant
b. Non Resonant
c. None of these
d. All of these
Answer: b. non-resonant

17. Rectangular Wave Guides are commonly used for ____ transmission at ____
frequencies.
a. Power, Microwave
 b. Power, Radio wave
c. Electric field, Radio wave
d. Electric field, Microwave
Answer: a. Power, Microwave
18. The Wilkinson Power divider is a ____.
a. 2 port network
b. 3 port network
c. 4 port network
d. None
Answer: c.4 port network
19. A plane wave propagating in circular waveguide results in _____ mode.
a. Neither TE nor TM
b. TE
c. TM
d. Either TE or TM
Answer: d. Either TE or TM
20. Magic Tee is ___ port device and is a _____.
a. 4, E-Plane Tee
b. 4, H-Plane Tee
c. 4, Combination of E plane & H-Plane Tee
d. None
Answer: c. 4, Combination of E plane & H-Plane Tee

21. Isolators are used to improve _____ of microwave generators, such as ____ , ____.
a. Amplitude stability, Pin Diode, Gunn Diode
b. Voltage stability, Pin Diode, Gunn Diode
c. Frequency stability, Klystrons, Magnetrons
d. Voltage stability, Klystrons, Magnetrons
Answer: c. Frequency stability, Klystrons, Magnetrons

22. Transferred Electron Devices (TED) are ____ devices, having _____ junctions,
operates with ___ electrons.
a. Layered, two , Warm
b. Layered, No, Warrm
c. Bulk, three, Hot
d. Bulk, No, Hot
Answer: d. Bulk, No, Hot

23. Ridley-Watkins-Hilsum (RWH) theory postulates_______.

a. Differential Negative resistance
b. Two valley theory
c. High Field Domain
d. All the above
Answer: d. All the above
 24. In Gunn oscillation mode, device is ____ due to cyclic formation of _____field
domain.
a. Stable, Low
b. Stable, High
c. Unstable, High
d. Unstable, Low
Answer: c. Unstable, High

25. The negative resistance is created by _____ effect of electrons in p-n junction.
a. Avalanche
b. Gunn
c. Tunnel
d. None
Answer: c. Tunnel

Part – B ( Apply Level ) – 2 Mark Questions

26. If the input power is divided in the ratio of 2:1 in a T- junction coupler and the
characteristic impedance of the 2 output lines is 150Ω and 75Ω, then the impedance
of the input line is:
a. 100Ω
b. 50Ω
c. 150Ω
d. None
Answer: b. 50Ω

27. Isolation of a directional coupler is a measure of ___.

a. Power to the coupled port
b. Power to the second port
c. Power to the uncoupled port
d. None of the mentioned
Answer: c. Power to the uncoupled port

28. Silicon IMPATT diode has power range of _______.

a. 10W at 10GHz to 1W at 94GHz.
b. 1W at 10GHz to 10W at 94GHz.
c. 10W at 94GHz to 1W at 10GHz.
d. 1W at 94GHz to 10W at 10GHz.
Ans: a. 10W at 10 GHz to 1W at 94GHz.

29. IMPATT diode has a frequency range of __________.

a. 10-300GHz.
b. 1-200GHz.
c. 30-500GHz.
 d. 50-3000GHz.
Ans: a. 10-300GHz.

30. The quadrature hybrid has a ---------------- phase shift between ports 2 and 3 (θ = φ = π/2)
when fed at port 1.
a. 180
b. 270
c. 360
d. 90
Answer: d. 90

31. The angular frequency of magnetron when magnetic density is 0.34wb/m2 is

a. 59.81x1011radian
b. 5.981 x1011radian
c. 0.5981 x1011radian
d.none
Answer: c. 0.5981 x1011radian

32. The initial velocity of electron in TWT when the applied beam voltage is 20KV is
a. 0.0593 x 108 m/s
b. 0.593 x 108 m/s
c. 1.186 x 108 m/s
d. 1.186 x 108 cm/s
Answer: c. 1.186 x 108 m/s

33. The output power gain in TWT for interaction length N=13.49 and gain parameter C is
0.038 will be
a. 24.24db
b. 14.79db
c. 33.85db
d. 0db
Answer: b. 14.79db

A two cavity klystron amplifier is tuned to 3 GHz. The drift space length is 2cm an beam
current is 25mA. The catcher voltage is 0.3 times the beam voltage. It is assumed that the
gap length of the cavity << the drift space so that the input and output voltages are
inphase (β=1).

1
34. Compute power output and efficiency for N=5 4 .
a. 9.3W , 58.3%
b. 41.3W, 58.3%
c. 1.621W, 17.46%
d. none
Answer: c. 1.621W, 17.46%
1
35. The beam voltage and input voltage for maximum power output of N=54 is
a. 230V, 50V
b. 330V, 100V
c. 330V, 230V
d. 371V, 41.4V
Answer: d. 371V, 41.4V

36. The bunching parameter for maximum power output is

a. 1
b. 100
c. 1.84
d. 0.582
Answer: c. 1.84

𝟑
A reflex klystron operated at 9GHz is given a dc beam voltage of 600V for 1 𝟒 mode,
repeller space length of 1mm, dc beam current of 10mA. Beam coupling coefficient is
assumed to be 1.

37. Calculate the repeller voltage.

a.230V
b.229V
c.250V
d. 249V
Answer: d. 249V
38. The electronic efficiency is
a. 100% b. 50% c. 33% d. 22.74%
Answer: d. 22.74%
39. In a Gunn diode oscillator, the electron drift velocity was found to be 107 cm/second and
the effective length is 20 microns, then the intrinsic frequency is:
a) 5 GHz
b) 6 GHz
c) 4 GHz
d) 2 GHz
Answer: a. 5 GHz
40. If the length of the intrinsic region in IMPATT diode is 2 µm and the carrier drift velocity
are 107 cm/s, then the drift time of the carrier is:
a) 10-11 seconds
b) 2×10-11 seconds
c) 2.5×10-11 seconds
d) none of the mentioned
Answer: b. 2×10-11 seconds
 K.L.N. College of Engineering, Pottapalayam – 630 612.
(An Autonomous Institution, Affiliated to Anna University)

DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING

MCQ Practice - Question Bank

EC8701 & Antenna and Microwave Engineering

IV Year & VII semester
UNIT – V
MICROWAVE DESIGN PRINCIPLES
Part – A ( Remember / Understand Level ) – 1 Mark Questions

1. The smith cart can be used to convert the normalized impedance to admittance by a
rotation of ____.
a. 450
b. 600
c. 900
d. 1800
Answer: d. 1800

2. Gain of power amplifiers __________ with increase in operating frequency.

a. Increases linearly
b. Increases exponentially
c. Decreases linearly
d. Decreases exponentially
Answer: c. Decreases linearly
3. Output of RF mixer in a transmitting chain is ______.
a. lower frequency
b. higher voltage
c. lower voltage
d. higher frequency
Answer: d.higher frequency
4. High gain is not achievable at microwave frequencies using BJT amplifiers because of
_________.
a. device construction
b. complex architecture
c. Conditional stability
d. the ports not being perfectly matched
Answer: d. the ports not being perfectly matched

5. Stability condition of an amplifier circuit is usually____________.

a. frequency dependent
b. frequency independent
c. voltage dependent
d. voltage independent
Answer: a. frequency dependent
6. By using a series inductor at the source of a MOSFET it is possible to create a
______ impedance without adding noisy resistors.
a. resistive output
b. resistive input
c. conductive input
d. conductive output
Answer: b. resistive input
7. In a balanced amplifier, the individual amplifier stages can be optimized for
______, without concern for input and output matching.
a. gain flatness
b. reduced loss
c. robustness
d. Stability
Answer: a.gain flatness
8. Power amplifiers are used in final stages of RADAR and radio transmitters to
_____ the radiated power level.
a. Maintain
b. Increase
c. Decrease
d. None
Answer: b.Increase
9. The network is unconditionally stable if ________ for all passive source and load
impedances.
a. |Гin| < 1 and |Гout| < 1
b. |Гin| > 1 and |Гout| < 1
c. |Гin| = 1 and |Гout| = 1
d. |Гin| > 1 and |Гout| > 1
Answer: a. |Гin| < 1 and |Гout| < 1
10. ___________ is a measure of the degradation in the signal-to-noise ratio between the
input and output of the component.
a. System loss
b. Noise level
c. Noise figure
d. Signal power
Answer: c. Noise figure
11. Power amplifiers in the increasing order of efficiency is ____.
a. Class A, B, C
b. Class C, B, A
c. Class B, A, C
d. None
Answer: a. Class A, B, C
 12. In RF amplifiers, impedance matching is usually done with ________.
a. Transformer coupling
b. RC coupling
c. Direct coupling
d. Lumped reactance
Answer: a. Transformer coupling
13. Standing wave leads to _____ losses
a. Increased
b. Decreased
c. None
d. Either
Answer : a. Increased
14. The series resonant frequency of crystal oscillator is _____, _____.
a. ωS=√LC
b. ωS=√L/√C
c. ωS=1/√LC
d. ωS=√L+√C
Answer: c. ωS=1/√LC
15. The modulation index of Oscillator is θP=_____.
a. fM /Δf
b. Δf/fM
c. None
d. c/f
Answer: b. Δf/fM
16. The criterion on which oscillations are produced in the oscillator circuit is called:
a. Shannon’s criteria
b. Barkhausen Criteria
c. Colpitt’s criteria
d. None
Answer: b. Barkhausen Criteria
17. RF oscillators provide _____ outputs , which _____undesired harmonics and noise
sidebands.
a. Non-sinusoidal, minimizes
b. Sinusoidal, minimizes
c. Sinusoidal, maximizes,
d. Non-sinusoidal, maximizes
Answer: b. Sinusoidal, minimizes

18. A perfect filter would have zero_____ in Pass band and Infinite ______ in stop band .
a. Amplification, Insertion loss
b. Attenuation, Insertion loss
c. Insertion loss, Amplification
d. Insertion loss, Attenuation
Answer: d. Insertion loss, Attenuation
19. For microstrip and strip line technology which type of stub is preferred?
a. short stub
b. long stub
c. open stub
d. close stub
Answer: c. open stub

Part – B ( Apply Level ) – 2 Mark Questions

20. Calculate the lengths of 6th and 7th element involved in a 9-element Log-Periodic
array if k=1.2 and the 5th element is of length λ /2.
a. 6 λ, 7.2 λ
b. 0.72 λ, 0.6 λ
c. 0.6 λ, 0.72 λ
d. 1 λ, 1.2 λ
Answer: c. 0.6 λ, 0.72 λ
21. Calculate the angle of radiation for a Dolph Tchebyshev array with c = v, m = -1,
d = 1 m, λ = 0.8 m
a. 78.40
b. 74.80
c. 900
d. 73.40
Answer: a. 78.40
22. If the input power is divided in the ratio of 2:1 in a T- junction coupler and the
characteristic impedance of the 2 output lines is 150Ω and 75Ω, then the
impedance of the input line is:
a. 100Ω
b. 50Ω
c. 150Ω
d. None
Answer: b. 50Ω
23. A one port oscillator uses a negative resistance diode having Γ in=1.25∠400, Z0=50Ω
at its desired operating point, for f=6GHz. Design a load matching network for a
50Ω load impedance.
a. ZL=-Zin=44-123 Ω
b. ZL=-Zin=22-123 Ω
c. ZL=-Zin=11-0.23 Ω
d. ZL=-Zin=4.4-1.23 Ω
Answer: a. ZL=-Zin=44-123 Ω

24. Determine the image frequency for a frequency band (fRF) 869-894MHz and
Local Oscillator frequency band of (fLO) 956 to 981MHz.
a. -78MHz
 b. 78MHz
c. 87MHz
d. -87MHz
Answer: d. -87MHz
25. The disadvantage of frequency multiplier is that the noise level is _____by the
___ factor.
a. Increased, Additive
b. Decreased, Multiplication
c. Decreased, Additive
d. Increased, multiplication
Answer: d. Increased, multiplication
26. Check the stability of the Power amplifier using Rollet’s condition (K, Δ):
S11=0.593∠1780; S12=0.009∠-1270; S21=1.77∠-1060; S22=0.958∠1730
a. K= 5: Δ=0.1
b. K= 2.08: Δ=0.55
c. K=0.55: Δ=2.08
d. K= 1: Δ=1
Answer: b. K= 2.08: Δ=0.55
27. If a power amplifier has an output power of 10 W, and an amplifier gain of
16.4 dB, then the input drive power is:
a. 400mW
b. 225mW
c. 229mW
d. 240mW
Answer: c. 229mW

28. A low-pass composite filter with a cutoff frequency of 2 MHz and impedance
of 75Ω is to be designed. Calculate the component values.
a. L=11.94 μH: C= 2.12 nF
b. L=11.94 nH: C= 2.12 nF
c. L=13.94 μH: C= 2.15 nF
d. L=14.94 μH: C= 4.122 nF
Answer: a. L=11.94 μH: C= 2.12 nF

29. The following figure is Circuit for a single-ended FET mixer.

?
 a. lowpass
b. b) high pass
c. c)band pass
d. d)none of the above
Answer : a . lowpass

30. . The IS-54 digital cellular telephone system uses a receive frequency band of 869–
894 MHz, with a first IF frequency of 87 MHz and a channel bandwidth of 30 kHz.
What are the two possible ranges for the LO frequency? If the upper LO frequency
range is used, determine the image frequency range. Does the image frequency fall
within the receive passband?
a. outside the receive passband.
b. inside the receive passband.
c. within the receive passband
d. none of the above
Answer: a. outside the receive passband.

31. Two techniques employed for impedance matching?

a. single or multi studs
b. one or more quarter wave sections
c. both a and b
d. none of these
Answer : c. both a and b