Antennas Mock Test 6

10%

Question 1 of 10

1. In which of the following scanning the phase of the radiator is constant at one frequency?

Phase scanning

Both Phase and frequency scanning

Neither Frequency nor Phase scanning

Frequency scanning

Question 1 of 10

Question 2 of 10

2. The radiating pattern of single element multiplied by the array factor simply gives the ___________

Field strength of the array

Beamwidth of the array

Pattern multiplication

Normalized array factor

Question 2 of 10

Question 3 of 10

3. An 8-isotropic element end-fire array separated by a λ/4 distance has first null occurring at ____

150

Question 3 of 10

Question 4 of 10

4. A 4-isotropic element end-fire array separated by a λ/4 distance has first null occurring at ____________

150

Question 4 of 10

Question 5 of 10

5. Which of the following is the necessary condition to avoid grating lobes in N-Isotropic element end-fire array?

d < λ

d > λ/2

d < λ/2

d=λ

Question 5 of 10

Question 6 of 10

6. The isotropic element array radiation pattern depends on the nulls of the array factor only.

False

True

Question 6 of 10

Question 7 of 10

7. The array factor of 8 - isotropic elements of broadside array is given by ____

\(\frac{cos(2kdcosθ)}{2kdcosθ} \)

\(\frac{sin(2kdcosθ)}{2kdcosθ} \)

\(\frac{sin(2kdcosθ)}{kdcosθ} \)

\(\frac{sin(4kdcosθ)}{4kdcosθ} \)

Question 7 of 10

Question 8 of 10

8. The direction of the first minor lobe of 8 element isotropic broadside array separated by λ/2 is ___

90°

41.4°

67.7°

76.6°

Question 8 of 10

Question 9 of 10

9. Which of the following equation gives the incremental phase shift of the phase array radar with d element spacing and scan angle θ?

\(ᴪ=\frac{π}{d} λsinθ\)

\(ᴪ=\frac{2π}{λ} dsinθ\)

\(ᴪ=\frac{2π}{d} λsinθ\)

\(ᴪ=\frac{π}{λ} dsinθ\)

Question 9 of 10

Question 10 of 10

10. Which of the following cannot be the separation between elements in a broadside array to avoid grating lobes?

λ/2

4λ/2

5λ/2

3λ/2

Question 10 of 10