STUPIDSID
1(a)
Explain the following terms as related to antenna systems:
i) Beam area ii) Directivity iii) Power gain
iv) Effective aperture v) Radiation resistance.
i) Beam area ii) Directivity iii) Power gain
iv) Effective aperture v) Radiation resistance.
10 M
1(b)
Find the directivity of the power pattern given by U = Um sin 2θsin3ϕ; 0≤θ 0&leπ;
0≤ϕ≤θ0≤π.
0≤ϕ≤θ0≤π.
5 M
1(c)
An antenna has a field pattern given by E(θ)= cosθcos2θ for 0≤ θ≤90°. Find half power beam width (HPBW) and beam width between first nulls (BWFN).
5 M
2(a)
Derive an expression for array factor and relative field of linear array of 'n' isotropic point sources of equal magnitude and spacing.
8 M
2(b)
Complete the field patterns and find BWFN and HPBW for an array of 4 point sources spaced λ/6 distance apart. They have a phase difference of &pie;/3 between adjacent elements.
6 M
2(c)
Explain the principle of pattern multiplication with an example.
6 M
3(a)
Derive the far field components of short dipole.
7 M
3(b)
For a short dipole of λ/15 and loss resistance of 1 Ω Find:
i) Efficiency
ii) Radiation resistance
iii) Effective aperture
i) Efficiency
ii) Radiation resistance
iii) Effective aperture
6 M
3(c)
Write short notes on :
i0 V-antennas
ii) Folded dipole antennas
iii) Rhombic antenna.
i0 V-antennas
ii) Folded dipole antennas
iii) Rhombic antenna.
7 M
4(a)
Derive the far field expressions for small loop antenna.
7 M
4(b)
Explain patch or microstrip antennas with necessary sketch.
6 M
4(c)
With relevant sketches, explain the principle of Babinet's principle for complementary linear antennas.
7 M
5(a)
Explain the practical design considerations for the axial mode helical antennas.
10 M
5(b)
Write short notes on:
i) Yagi-Uda antena
ii) Corner reflection antenna.
i) Yagi-Uda antena
ii) Corner reflection antenna.
10 M
6(a)
Explain the constructional details of Sleeve antanna and Turnstile antenna.
8 M
6(b)
Write short notes on :
i) Embedded antennas
ii) Ultra wideband antennas
iii) Plasma antennas
i) Embedded antennas
ii) Ultra wideband antennas
iii) Plasma antennas
12 M
7(a)
Derive an expression for wave tilt of surface wave.
8 M
7(b)
Explain duct propagation in detail.
6 M
7(c)
Estimate the wave tilt in degrees of the surface wave over on earth of 5 millimhos conductivity and relative permitivity of 10 at 1 Mhz.
6 M
8(a)
Derive an expression for refractive index of an ionospheric propagation.
6 M
8(b)
A high frequency link is established for a range of 2000 km. If the reflection region of ionosphere is at a height of 200 km and has a critical frequency of 6 Mhz, calculate maximum usable frequency (MUF).
6 M
8(c)
Define the following terma related to ionospheric propagation:
i) MUF
ii) Critical frequency
iii) Virtual height
iv) Skip distance
i) MUF
ii) Critical frequency
iii) Virtual height
iv) Skip distance
8 M
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