Contents

• Unit 1. ANTENNA FUNDAMENTALS– Review of Electromagnetic theory. Short elementary dipole and its fields. Basic antenna parameters - Radiation pattern, beamwidth, beam solid angle, directivity, efficiency, gain, radiation intensity, radiation resistance, input impedance and polarization. Receiving antenna- Reciprocity, effective length and aperture, antenna temperature.

  Unit 2. ANTENNA ARRAYS– Point source, Array of two isotropic point sources. Uniform array of N point sources and array factor –Examples of 4 element broadside and endfire arrays. N-element linear array of elementary dipoles and principle of pattern multiplication. Two element array of elementary dipoles- Excitation with different relative phase shift and for different spacing.

  Unit 3. DIFFERENT TYPES OF ANTENNAS– Thin linear antenna and thin halfwave dipole. V- and Rhombic antennas. Monopole antenna, Small loop antenna, Folded dipole and Yagi-Uda antenna. Broadband antennas – Broadband basics, log-periodic dipole array. Reflector antennas –Flat sheet, corner and parabolic reflector antennas. Slot, Horn and Lens antennas, Helical antennas. Microstrip patch antennas- Rectangular patch antenna, Twoelement microstrip patch. Antenna Measurements- Antenna radiation pattern, gain, directivity and polarization. .

  Unit 4. GROUND WAVE PROPAGATION- Mechanism of radio wave propagation. Theory of ground reflection- Plane earth reflection, reflection factors for horizontal and vertical polarizations. Refraction and diffraction of radio waves. Space and surface waves. Tropospheric propagation, duct propagation and tropospheric scattering.

  Unit 5. IONOSPHERIC PROPAGATION: Various ionospheric layers, Electrical properties of the ionosphere and their effects on wave propagation. Critical frequency, virtual height, skip distance, maximum usable frequency. Multiple hop transmission. Effect of earth's magnetic field and Faraday rotation. Solar activity and meteorological conditions on wave propagation.