Antenna And Wave Propagation

Physical concept of radiation in single wire, Two wire and dipole, Current distribution on a thin wire antenna.Fundamental Parameters of AntennaRadiation pattern, Radiation power density, Radiation intensity, Directivity, Gain, Antenna efficiency, Beamwidth, Bandwidth, Polarization, Antenna input impedance, Elementary idea about self and mutual impedance, Radiation efficiency, Effective aperture, Antenna temperature.Linear Wire AntennasRetarded potential, Infinitesimal dipole, Current distribution of short dipole and half wave dipole, Far-field, Radiating near-field and reactive near-field region, Monopole and half wave dipole.Antenna ArraysArray of two point sources, Array factor, n-element linear array with uniform amplitude and spacing, Analysis of broadside array, Ordinary end-fire array, Hansen-Woodyard end fire array, n-element linear array with non-uniform spacing, Analysis of binomial and Dolph-Tchebyscheff array, Scanning array, Superdirective array.Aperture AntennasField equivalence principle, Rectangular and circular aperture antennas, Horn antenna, Babinet's principle, Slot antenna, Reflector antenna.Ground Wave PropagationFriis free space equation, Reflection from earth's surface, Surface and space wave propagation for vertical and horizontal dipole, Field strength of space wave, Range of space wave propagation, Effective earth's radius, Effect of earth imperfections and atmosphere on space wave propagation, Modified refractive index, Duct propagation, Tropospheric propagation.Ionospheric PropagationStructure of ionosphere, Propagation of radio waves through ionosphere, Refractive index of ionosphere, Reflection and refraction of waves by ionosphere, Critical frequency, Maximum usable frequency, Optimum working frequency, Lowest usable high frequency, Virtual height, Skip distance, Effect of earth's magnetic field.