1(a) Write a note on
directivity and gain of antennas. (4 Marks)

(b) What is a monopole?
(4 Marks)

(c) Small loop antennas
have considerable ohmic resistance. Explain. Mention some applications of Small
loop antennas. (8 Marks)

(d) A 2m long dipole
made of 6.35 mm diameter aluminium is operated at 500 kHz. Assuming current is
uniform and triangular, determine its radiation frequency. (4 Marks)

2 (a) What is an
isotropic radiator? (4 Marks)

(b) What are HP and
BWFN? Show that HP is roughly one half of the corresponding BWFN value for
long, uniformly excited linear arrays. (6 Marks)

(c) What is a beam
forming network? (4 Marks)

(d) An interferometer
is constructed from five collinear half-wave dipoles spaced two wavelengths
apart. Sketch the polar plot of the complete array pattern. (6 Marks)

3 (a) Construct the
linear, polar plot of the pattern factor for a broadside cosine-tapered line
source that is three wavelengths long. (8 Marks)

(b) What are straight
wire diploes? (4 Marks)

(c) The simplistic
beauty of the Yagi is revealed by lengthening the parasite. Explain. (4 Marks)

(d) Design an optimum
directivity vee dipole to have a directivity of 6 dB. (4 Marks)

4 (a) Differentiate
between normal mode helix antenna and axial mode helix antenna. (6 Marks)

(b) A sinuous antenna
is more complicated than the spiral antenna. Explain why? (4 Marks)

(c) Derive optimum
pyramidal horn design equation. (6 Marks)

(d) Show that the
directivity-beamwidth product for a uniform phase rectangular aperture with
cosine amplitude taper in the H-plane and uniform amplitude in the E-plane is
35230 square degrees. (4 Marks)

5 (a) Explain
Woodward-Lawson sampling method. (6 Marks)

(b) Explain
Dolph-Chebyshev linear array method of antenna synthesis. (6 Marks)

(c) What is radar
equation? Define radar cross section. (4 Marks)

(d) Calculate the
antenna factor of a matched antenna operating at 30 MHz with a gain of 3 dB and
terminated with a 50 Ω resistor. (4 Marks)

6 (a) Derive
Pocklington’s integral equation. (8 Marks)

(b) Explain why delta
gap model is known as slice generator. (4 Marks)

(c) What are compressed
matrices? (4 Marks)

(d) Sketch a wire grid
model for a square plate 1λ1λ. If pulse expansion functions
are to be used, how many unknowns will your model have? (4 Marks)

7 (a) What is FD-TD
approach? Explain with the help of a flowchart. (8 Marks)

(b) Write a detailed
note on Vivaldi slotline array. (8 Marks)

(c) Can numerical
dispersion occur in a non-dispersive medium? (4 Marks)

8 (a) Explain the
postulates of Keller’s theory. (4 Marks)

(b) Explain the PTD
formulation for surfaces with perfectly cutting edges. (6 Marks)

(c) Using physical
optics, show that the radar cross section of a flat rectangular plate at normal
incidence is σ = 4π (A

^{2}/λ^{2}) where A is the area of the plate. (6 Marks)
(d) Write a note on the
importance of GTD method in antenna and scattering problems. (4 Marks)

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