Antenna and Propagation

a. Derive an expression for wave tilt of surface wave.

c. With relevant sketches, explain the principle of Babinet's principle for complementary linear antennas

a. Explain the practical design considerations for the axial mode helical antennas.

Write short note on:

1) Yagi-Uda antenna 

Write short note on:

2) Corner reflector antenna

a. Explain the constructional details of Sleeve antenna and Turnstile antenna.

b. Write short note on:

i) Embedded antennas

b. Write short note on:

ii) Ultra wideband antennas

b. Write short note on:

iii) Plasma antennas

b. Explain patch or microstrip antennas with necessary sketch.

b. Explain duct propagation in detail.

c. Estimate the wave tilt in degrees of the surface wave over an earth of 5 millimho s conductivity and relative permittivity of 10 at 1 MHz.

a. Derive an expression for refractive index of an ionospheric propagation.

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).

Define the following term related to ionospheric propagation

i) MUF 

Define the following term related to ionospheric propagation

ii) Critical frequency

Define the following term related to ionospheric propagation

ii) Virtual height

Define the following term related to ionospheric propagation

iv) Skip distance

c. Explain the principle of pattern multiplication with an example.

 Explain the following term as related to antenna systems:

ii) Directivity

 Explain the following term as related to antenna systems:

iii) Power gain

 Explain the following term as related to antenna systems:

iv) Effective aperture

 Explain the following term as related to antenna systems:

v) Radiation resistance

b. Find the directivity of the power pattern given by  

c. An antenna has a field pattern given by  Find half power beam width (HPBW) and beam width between first nells (BWFN).

a. Derive an expression for array factor and relative field of linear array of 'n' isotropic point sources of equal magnitude and spacing.

b. Complete the field patterns and find BWFN and HPBW for an array of 4 point sources spaced /6 distance apart. They have a phase difference of /3 between adjacent elements.

 Explain the following term as related to antenna systems:

i) Beam area

a. Derive the far field components of short dipole.

b. For a short dipole of /15 long and loss resistance of 1. Find: 

i) Efficiency

b. For a short dipole of /15 long and loss resistance of 1. Find: 

ii) Radiation resistance

b. For a short dipole of /15 long and loss resistance of 1. Find: 

iii) Effective aperture

Write short note on:

i) V-antennas

Write short note on:

ii) Folded dipole antennas

Write short note on:

iii) Rhombic antenna

a. Derive the far field expressions for small loop antenna.