1
GATE ECE 1998
MCQ (Single Correct Answer)
+1
-0.3
The far field of an antenna varies with distance r as
A
1/r
B
1 / $${r^2}$$
C
1 / $${r^3}$$
D
$${1 \over {\sqrt r }}$$
2
GATE ECE 1998
Subjective
+5
-0
A rectangular waveguide with inner dimensions 6 cm $$ \times $$ 3 cm has been designed for a single mode operation. Find the possible frequency range of operation such that the lowest frequency is 5% above the cut off and the highest frequency is 5% below the cut off of the next higher mode.
3
GATE ECE 1998
MCQ (Single Correct Answer)
+1
-0.3
The vector $$\mathop H\limits^ \to $$ in the far field of an antenna satisfiels
A
$$\nabla .\,\mathop H\limits^ \to = 0\,\,and\,\,\nabla \times \,\mathop H\limits^ \to = 0\,$$
B
$$\nabla .\,\mathop H\limits^ \to \ne 0\,\,and\,\,\nabla \times \,\mathop H\limits^ \to \ne 0$$
C
$$\nabla .\,\mathop H\limits^ \to = 0\,\,and\,\,\nabla \times \,\mathop H\limits^ \to \ne 0\,\,$$
D
$$\nabla .\,\mathop H\limits^ \to \ne 0\,\,and\,\,\nabla \times \,\mathop H\limits^ \to = 0\,\,$$
4
GATE ECE 1998
MCQ (Single Correct Answer)
+1
-0.3
An antenna in free space receives 2$$\mu $$ W of power when the incident electric field is 20 m V/m rms. The effective aperture of the antenna is
A
0.005 $${m^2}$$
B
0.05 $${m^2}$$
C
1.885 $${m^2}$$
D
3.77 $${m^2}$$