1
GATE ECE 2016 Set 1
MCQ (Single Correct Answer)
+1
-0.3
The propagation constant of a lossy transmission line is (2 + j5) $${m^{ - 1}}$$ and its characteristic impedance is (50 + j0) $$\Omega $$ at $$\omega = \,{10^6}\,rad\,{S^{ - 1}}$$. The values of the line constants L, C, R, G are, respectively,
A
$$\matrix{ {L = \,200\,\mu H/\,m,\,C = 0.1\,\,\mu F/\,m,\,} \cr {R = 50\,\,\Omega /m,\,G = 0.02\,S/m,} \cr } $$
B
$${\matrix{ {L = \,250\,\mu H/\,m,\,C = 0.1\,\,\mu F/\,m,\,} \cr {R = 100\,\,\Omega /m,\,G = 0.04\,S/m,} \cr } }$$
C
$${\matrix{ {L = \,200\,\mu H/\,m,\,C = 0.2\,\,\mu F/\,m,\,} \cr {R = 100\,\,\Omega /m,\,G = 0.02\,S/m,} \cr } }$$
D
$${\matrix{ {L = \,250\,\mu H/\,m,\,C = 0.2\,\,\mu F/\,m,\,} \cr {R = 50\,\,\Omega /m,\,G = 0.04\,S/m,} \cr } }$$
2
GATE ECE 2016 Set 1
MCQ (Single Correct Answer)
+2
-0.6
The electric field of a uniform plane wave travelling along the negative $$z$$ direction is given by the following equation: $$$\overrightarrow E {}_w^i = \left( {{{\widehat a}_{_x}} + j{{\widehat a}_{_y}}} \right){E_0}{e^{jkz}}$$$

This wave is incident upon a receiving antenna placed at the origin and whose radiated electric field towards the incident wave is given by the following equation:

$$${\overrightarrow E _{_a}} = \left( {{{\widehat a}_{_x}} + 2{{\widehat a}_{_y}}} \right){E_1}{1 \over r}{e^{ - jkr}}$$$

The polarization of the incident wave, the polarization of the antenna and losses due to the polarization mismatch are, respectively,

A
Linear, Circular (clockwise), $$−5dB$$
B
Circular (clockwise), Linear, $$−5dB$$
C
Circular (clockwise), Linear, $$−3dB$$
D
Circular (anti clockwise), Linear, $$−3dB$$
3
GATE ECE 2016 Set 1
MCQ (Single Correct Answer)
+2
-0.6
An antenna pointing in a certain direction has a noise temperature of $$50K$$. The ambient temperature is $$290K$$. The antenna is connected to a pre-amplifier that has a noise figure of 2 dB and an available gain of 40 dB over an effective bandwidth of $$12$$ $$MHz$$. The effective input noise temperature $${T_e}$$ for the amplifier and the noise power $${P_{ao}}$$ at the output of the preamplifier, respectively, are
A
$${T_e} = 169.36K$$ and $${P_{ao}} = 3.73 \times {10^{ - 10}}\,\,\,W$$
B
$${T_e} = 170.8K$$ and $${P_{ao}} = 4.56 \times {10^{ - 10}}\,\,\,W$$
C
$${T_e} = 182.5K$$ and $${P_{ao}} = 3.85 \times {10^{ - 10}}\,\,\,W$$
D
$${T_e} = 160.62K$$ and $${P_{ao}} = 4.6 \times {10^{ - 10}}\,\,\,W$$
4
GATE ECE 2016 Set 1
Numerical
+2
-0
Two lossless X-band horn antennas are separated by a distance of $$200\lambda $$. The amplitude reflection coefficients at the terminals of the transmitting and receiving antennas are $$0.15$$ and $$0.18$$, respectively. The maximum directivities of the transmitting and receiving antennas (over the isotropic antenna) are $$18$$ $$dB$$ and $$22$$ $$dB$$, respectively. Assuming that the input power in the lossless transmission line connected to the antenna is $$2$$ $$W$$, and that the antennas are perfectly aligned and polarization matched, the power ( in mW) delivered to the load at the receiver is ________ .
Your input ____
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